diff --git a/docs-v2/openapi-v1.yaml b/docs-v2/openapi-v1.yaml
index cd7d1ae74..4f5654243 100755
--- a/docs-v2/openapi-v1.yaml
+++ b/docs-v2/openapi-v1.yaml
@@ -2672,9 +2672,23 @@ paths:
       tags:
       - transaction
       summary: Get the metadata blob for offline signers.
-      description: Returns the minimal metadata ("metadata blob" or "proof") needed by offline
+      description: >-
+        Returns the minimal metadata ("metadata blob" or "proof") needed by offline
         signers to decode a transaction's signing payload, along with the metadata
         hash for the CheckMetadataHash signed extension per RFC-0078.
+
+
+        The metadata blob contains type definitions needed to decode the specific
+        transaction, Merkle proofs verifying these types are part of the full metadata,
+        and extra chain info (specVersion, specName, base58Prefix, decimals, tokenSymbol).
+
+
+        Offline signers can use this to decode the transaction to display what the user
+        is signing and verify the metadata subset matches the on-chain metadata via
+        Merkle proofs.
+
+
+        Reference: RFC-0078 https://polkadot-fellows.github.io/RFCs/approved/0078-merkleized-metadata.html
       operationId: getTransactionMetadataBlob
       requestBody:
         $ref: '#/components/requestBodies/TransactionMetadataBlob'
@@ -3677,6 +3691,88 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/RuntimeSpec'
+  /runtime/apis:
+    get:
+      tags:
+      - runtime
+      summary: List runtime APIs available in metadata.
+      description: Returns runtime API summaries (name, id, method count) for the selected block. Requires metadata v15 or higher.
+      parameters:
+      - name: at
+        in: query
+        description: Block at which to retrieve runtime API metadata.
+        required: false
+        schema:
+          type: string
+          description: Block identifier, as the block height or block hash.
+          format: unsignedInteger or $hex
+      responses:
+        "200":
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RuntimeApis'
+  /runtime/apis/{apiId}:
+    get:
+      tags:
+      - runtime
+      summary: Get a specific runtime API with method signatures.
+      description: Returns full method metadata (inputs, output, docs) for one runtime API.
+      parameters:
+      - name: apiId
+        in: path
+        description: Runtime API id or name.
+        required: true
+        schema:
+          type: string
+      - name: at
+        in: query
+        description: Block at which to retrieve runtime API metadata.
+        required: false
+        schema:
+          type: string
+          description: Block identifier, as the block height or block hash.
+          format: unsignedInteger or $hex
+      responses:
+        "200":
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RuntimeApi'
+  /runtime/apis/{apiId}/{methodId}:
+    post:
+      tags:
+      - runtime
+      summary: Call a runtime API method with named JSON parameters.
+      description: Invokes a runtime API method exposed by metadata for the selected block.
+      parameters:
+      - name: apiId
+        in: path
+        description: Runtime API id or name.
+        required: true
+        schema:
+          type: string
+      - name: methodId
+        in: path
+        description: Runtime API method id or name.
+        required: true
+        schema:
+          type: string
+      requestBody:
+        required: false
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/RuntimeApiCallRequest'
+      responses:
+        "200":
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RuntimeApiCall'
   /rc/runtime/spec:
     get:
       tags:
@@ -3699,6 +3795,88 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/RuntimeSpec'
+  /rc/runtime/apis:
+    get:
+      tags:
+      - rc runtime
+      summary: List relay chain runtime APIs available in metadata.
+      description: Returns runtime API summaries (name, id, method count) for the selected relay chain block. Requires metadata v15 or higher.
+      parameters:
+      - name: at
+        in: query
+        description: Relay chain block hash or height at which to query.
+        required: false
+        schema:
+          type: string
+          description: Block identifier, as the block height or block hash.
+          format: unsignedInteger or $hex
+      responses:
+        "200":
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RuntimeApis'
+  /rc/runtime/apis/{apiId}:
+    get:
+      tags:
+      - rc runtime
+      summary: Get a specific relay chain runtime API with method signatures.
+      description: Returns full method metadata (inputs, output, docs) for one relay chain runtime API.
+      parameters:
+      - name: apiId
+        in: path
+        description: Runtime API id or name.
+        required: true
+        schema:
+          type: string
+      - name: at
+        in: query
+        description: Relay chain block hash or height at which to query.
+        required: false
+        schema:
+          type: string
+          description: Block identifier, as the block height or block hash.
+          format: unsignedInteger or $hex
+      responses:
+        "200":
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RuntimeApi'
+  /rc/runtime/apis/{apiId}/{methodId}:
+    post:
+      tags:
+      - rc runtime
+      summary: Call a relay chain runtime API method with named JSON parameters.
+      description: Invokes a relay chain runtime API method exposed by metadata for the selected block.
+      parameters:
+      - name: apiId
+        in: path
+        description: Runtime API id or name.
+        required: true
+        schema:
+          type: string
+      - name: methodId
+        in: path
+        description: Runtime API method id or name.
+        required: true
+        schema:
+          type: string
+      requestBody:
+        required: false
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/RuntimeApiCallRequest'
+      responses:
+        "200":
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RuntimeApiCall'
   /rc/runtime/metadata:
     get:
       tags:
@@ -7895,6 +8073,173 @@ components:
         code:
           type: string
           format: hex
+    RuntimeApiMethodInput:
+      type: object
+      properties:
+        name:
+          type: string
+          description: Input argument name as presented by metadata.
+        id:
+          type: string
+          description: Camel-cased identifier used for argument matching.
+        typeId:
+          type: string
+          description: Runtime lookup type id.
+        type:
+          type: string
+          description: Resolved type name when lookup resolution is available.
+    RuntimeApiMethodOutput:
+      type: object
+      properties:
+        typeId:
+          type: string
+          description: Runtime lookup type id.
+        type:
+          type: string
+          description: Resolved type name when lookup resolution is available.
+    DeprecationInfo:
+      type: object
+      nullable: true
+      description: Deprecation status of a runtime API or method. Null when not available (metadata v15). Present in metadata v16+.
+      properties:
+        type:
+          type: string
+          enum:
+            - NotDeprecated
+            - DeprecatedWithoutNote
+            - Deprecated
+          description: Deprecation variant.
+        note:
+          type: string
+          nullable: true
+          description: Deprecation note. Only set when type is Deprecated.
+        since:
+          type: string
+          nullable: true
+          description: Version since which the item is deprecated. Only set when type is Deprecated and a since value was provided.
+    RuntimeApiMethodDescription:
+      type: object
+      properties:
+        name:
+          type: string
+          description: Runtime method name as presented by metadata.
+        id:
+          type: string
+          description: Camel-cased runtime method identifier.
+        docs:
+          type: string
+          description: Runtime method documentation joined into a single string.
+        inputs:
+          type: array
+          items:
+            $ref: '#/components/schemas/RuntimeApiMethodInput'
+        output:
+          $ref: '#/components/schemas/RuntimeApiMethodOutput'
+        deprecationInfo:
+          $ref: '#/components/schemas/DeprecationInfo'
+    RuntimeApiSummary:
+      type: object
+      properties:
+        name:
+          type: string
+          description: Runtime API name as presented by metadata.
+        id:
+          type: string
+          description: Camel-cased runtime API identifier.
+        docs:
+          type: string
+          description: Runtime API documentation joined into a single string.
+        methodCount:
+          type: integer
+          description: Number of methods exposed by this runtime API.
+        methods:
+          type: array
+          items:
+            type: object
+            properties:
+              name:
+                type: string
+              id:
+                type: string
+    RuntimeApiDescription:
+      type: object
+      properties:
+        name:
+          type: string
+          description: Runtime API name as presented by metadata.
+        id:
+          type: string
+          description: Camel-cased runtime API identifier.
+        docs:
+          type: string
+          description: Runtime API documentation joined into a single string.
+        version:
+          type: integer
+          nullable: true
+          description: Runtime API version number. Null when not available (metadata v15). Present in metadata v16+.
+        deprecationInfo:
+          $ref: '#/components/schemas/DeprecationInfo'
+        methods:
+          type: array
+          items:
+            $ref: '#/components/schemas/RuntimeApiMethodDescription'
+    RuntimeApis:
+      type: object
+      properties:
+        at:
+          $ref: '#/components/schemas/BlockIdentifiers'
+        apis:
+          type: array
+          items:
+            $ref: '#/components/schemas/RuntimeApiSummary'
+    RuntimeApi:
+      type: object
+      properties:
+        at:
+          $ref: '#/components/schemas/BlockIdentifiers'
+        api:
+          $ref: '#/components/schemas/RuntimeApiDescription'
+    RuntimeApiCallRequest:
+      type: object
+      properties:
+        at:
+          type: string
+          description: Optional block hash or height to execute the call at. Defaults to finalized head.
+          format: unsignedInteger or $hex
+        params:
+          type: object
+          additionalProperties: true
+          description: Named JSON parameters keyed by method argument names or arg{index}. Omit this field entirely for runtime API methods that do not take parameters. For Option<T> arguments, either omit the argument key (defaults to null) or pass it explicitly as null.
+    RuntimeApiCall:
+      type: object
+      properties:
+        at:
+          $ref: '#/components/schemas/BlockIdentifiers'
+        api:
+          type: object
+          properties:
+            name:
+              type: string
+            id:
+              type: string
+        method:
+          type: object
+          properties:
+            name:
+              type: string
+            id:
+              type: string
+        result:
+          description: Runtime API call result serialized via codec.toJSON(). Can be any JSON value.
+          nullable: true
+          oneOf:
+            - type: object
+              additionalProperties: true
+            - type: array
+              items: {}
+            - type: string
+            - type: number
+            - type: boolean
     RuntimeDispatchInfo:
       type: object
       properties:
@@ -8625,6 +8970,12 @@ components:
           schema:
             $ref: '#/components/schemas/DryRunBody'
       required: true
+    RuntimeApiCall:
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/RuntimeApiCallRequest'
+      required: true
     TransactionMetadataBlob:
       content:
         application/json:
diff --git a/docs/src/openapi-v1.yaml b/docs/src/openapi-v1.yaml
index d8b054b13..4f5654243 100755
--- a/docs/src/openapi-v1.yaml
+++ b/docs/src/openapi-v1.yaml
@@ -3691,6 +3691,88 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/RuntimeSpec'
+  /runtime/apis:
+    get:
+      tags:
+      - runtime
+      summary: List runtime APIs available in metadata.
+      description: Returns runtime API summaries (name, id, method count) for the selected block. Requires metadata v15 or higher.
+      parameters:
+      - name: at
+        in: query
+        description: Block at which to retrieve runtime API metadata.
+        required: false
+        schema:
+          type: string
+          description: Block identifier, as the block height or block hash.
+          format: unsignedInteger or $hex
+      responses:
+        "200":
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RuntimeApis'
+  /runtime/apis/{apiId}:
+    get:
+      tags:
+      - runtime
+      summary: Get a specific runtime API with method signatures.
+      description: Returns full method metadata (inputs, output, docs) for one runtime API.
+      parameters:
+      - name: apiId
+        in: path
+        description: Runtime API id or name.
+        required: true
+        schema:
+          type: string
+      - name: at
+        in: query
+        description: Block at which to retrieve runtime API metadata.
+        required: false
+        schema:
+          type: string
+          description: Block identifier, as the block height or block hash.
+          format: unsignedInteger or $hex
+      responses:
+        "200":
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RuntimeApi'
+  /runtime/apis/{apiId}/{methodId}:
+    post:
+      tags:
+      - runtime
+      summary: Call a runtime API method with named JSON parameters.
+      description: Invokes a runtime API method exposed by metadata for the selected block.
+      parameters:
+      - name: apiId
+        in: path
+        description: Runtime API id or name.
+        required: true
+        schema:
+          type: string
+      - name: methodId
+        in: path
+        description: Runtime API method id or name.
+        required: true
+        schema:
+          type: string
+      requestBody:
+        required: false
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/RuntimeApiCallRequest'
+      responses:
+        "200":
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RuntimeApiCall'
   /rc/runtime/spec:
     get:
       tags:
@@ -3713,6 +3795,88 @@ paths:
             application/json:
               schema:
                 $ref: '#/components/schemas/RuntimeSpec'
+  /rc/runtime/apis:
+    get:
+      tags:
+      - rc runtime
+      summary: List relay chain runtime APIs available in metadata.
+      description: Returns runtime API summaries (name, id, method count) for the selected relay chain block. Requires metadata v15 or higher.
+      parameters:
+      - name: at
+        in: query
+        description: Relay chain block hash or height at which to query.
+        required: false
+        schema:
+          type: string
+          description: Block identifier, as the block height or block hash.
+          format: unsignedInteger or $hex
+      responses:
+        "200":
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RuntimeApis'
+  /rc/runtime/apis/{apiId}:
+    get:
+      tags:
+      - rc runtime
+      summary: Get a specific relay chain runtime API with method signatures.
+      description: Returns full method metadata (inputs, output, docs) for one relay chain runtime API.
+      parameters:
+      - name: apiId
+        in: path
+        description: Runtime API id or name.
+        required: true
+        schema:
+          type: string
+      - name: at
+        in: query
+        description: Relay chain block hash or height at which to query.
+        required: false
+        schema:
+          type: string
+          description: Block identifier, as the block height or block hash.
+          format: unsignedInteger or $hex
+      responses:
+        "200":
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RuntimeApi'
+  /rc/runtime/apis/{apiId}/{methodId}:
+    post:
+      tags:
+      - rc runtime
+      summary: Call a relay chain runtime API method with named JSON parameters.
+      description: Invokes a relay chain runtime API method exposed by metadata for the selected block.
+      parameters:
+      - name: apiId
+        in: path
+        description: Runtime API id or name.
+        required: true
+        schema:
+          type: string
+      - name: methodId
+        in: path
+        description: Runtime API method id or name.
+        required: true
+        schema:
+          type: string
+      requestBody:
+        required: false
+        content:
+          application/json:
+            schema:
+              $ref: '#/components/schemas/RuntimeApiCallRequest'
+      responses:
+        "200":
+          description: successful operation
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/RuntimeApiCall'
   /rc/runtime/metadata:
     get:
       tags:
@@ -7909,6 +8073,173 @@ components:
         code:
           type: string
           format: hex
+    RuntimeApiMethodInput:
+      type: object
+      properties:
+        name:
+          type: string
+          description: Input argument name as presented by metadata.
+        id:
+          type: string
+          description: Camel-cased identifier used for argument matching.
+        typeId:
+          type: string
+          description: Runtime lookup type id.
+        type:
+          type: string
+          description: Resolved type name when lookup resolution is available.
+    RuntimeApiMethodOutput:
+      type: object
+      properties:
+        typeId:
+          type: string
+          description: Runtime lookup type id.
+        type:
+          type: string
+          description: Resolved type name when lookup resolution is available.
+    DeprecationInfo:
+      type: object
+      nullable: true
+      description: Deprecation status of a runtime API or method. Null when not available (metadata v15). Present in metadata v16+.
+      properties:
+        type:
+          type: string
+          enum:
+            - NotDeprecated
+            - DeprecatedWithoutNote
+            - Deprecated
+          description: Deprecation variant.
+        note:
+          type: string
+          nullable: true
+          description: Deprecation note. Only set when type is Deprecated.
+        since:
+          type: string
+          nullable: true
+          description: Version since which the item is deprecated. Only set when type is Deprecated and a since value was provided.
+    RuntimeApiMethodDescription:
+      type: object
+      properties:
+        name:
+          type: string
+          description: Runtime method name as presented by metadata.
+        id:
+          type: string
+          description: Camel-cased runtime method identifier.
+        docs:
+          type: string
+          description: Runtime method documentation joined into a single string.
+        inputs:
+          type: array
+          items:
+            $ref: '#/components/schemas/RuntimeApiMethodInput'
+        output:
+          $ref: '#/components/schemas/RuntimeApiMethodOutput'
+        deprecationInfo:
+          $ref: '#/components/schemas/DeprecationInfo'
+    RuntimeApiSummary:
+      type: object
+      properties:
+        name:
+          type: string
+          description: Runtime API name as presented by metadata.
+        id:
+          type: string
+          description: Camel-cased runtime API identifier.
+        docs:
+          type: string
+          description: Runtime API documentation joined into a single string.
+        methodCount:
+          type: integer
+          description: Number of methods exposed by this runtime API.
+        methods:
+          type: array
+          items:
+            type: object
+            properties:
+              name:
+                type: string
+              id:
+                type: string
+    RuntimeApiDescription:
+      type: object
+      properties:
+        name:
+          type: string
+          description: Runtime API name as presented by metadata.
+        id:
+          type: string
+          description: Camel-cased runtime API identifier.
+        docs:
+          type: string
+          description: Runtime API documentation joined into a single string.
+        version:
+          type: integer
+          nullable: true
+          description: Runtime API version number. Null when not available (metadata v15). Present in metadata v16+.
+        deprecationInfo:
+          $ref: '#/components/schemas/DeprecationInfo'
+        methods:
+          type: array
+          items:
+            $ref: '#/components/schemas/RuntimeApiMethodDescription'
+    RuntimeApis:
+      type: object
+      properties:
+        at:
+          $ref: '#/components/schemas/BlockIdentifiers'
+        apis:
+          type: array
+          items:
+            $ref: '#/components/schemas/RuntimeApiSummary'
+    RuntimeApi:
+      type: object
+      properties:
+        at:
+          $ref: '#/components/schemas/BlockIdentifiers'
+        api:
+          $ref: '#/components/schemas/RuntimeApiDescription'
+    RuntimeApiCallRequest:
+      type: object
+      properties:
+        at:
+          type: string
+          description: Optional block hash or height to execute the call at. Defaults to finalized head.
+          format: unsignedInteger or $hex
+        params:
+          type: object
+          additionalProperties: true
+          description: Named JSON parameters keyed by method argument names or arg{index}. Omit this field entirely for runtime API methods that do not take parameters. For Option<T> arguments, either omit the argument key (defaults to null) or pass it explicitly as null.
+    RuntimeApiCall:
+      type: object
+      properties:
+        at:
+          $ref: '#/components/schemas/BlockIdentifiers'
+        api:
+          type: object
+          properties:
+            name:
+              type: string
+            id:
+              type: string
+        method:
+          type: object
+          properties:
+            name:
+              type: string
+            id:
+              type: string
+        result:
+          description: Runtime API call result serialized via codec.toJSON(). Can be any JSON value.
+          nullable: true
+          oneOf:
+            - type: object
+              additionalProperties: true
+            - type: array
+              items: {}
+            - type: string
+            - type: number
+            - type: boolean
     RuntimeDispatchInfo:
       type: object
       properties:
@@ -8639,6 +8970,12 @@ components:
           schema:
             $ref: '#/components/schemas/DryRunBody'
       required: true
+    RuntimeApiCall:
+      content:
+        application/json:
+          schema:
+            $ref: '#/components/schemas/RuntimeApiCallRequest'
+      required: true
     TransactionMetadataBlob:
       content:
         application/json:
diff --git a/src/chains-config/acalaControllers.ts b/src/chains-config/acalaControllers.ts
index b24c5cb13..c9bec3e2f 100644
--- a/src/chains-config/acalaControllers.ts
+++ b/src/chains-config/acalaControllers.ts
@@ -32,6 +32,7 @@ export const acalaControllers: ControllerConfig = {
 		'NodeVersion',
 		'PalletsStorage',
 		'Paras',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/assetHubKusamaControllers.ts b/src/chains-config/assetHubKusamaControllers.ts
index 834b4d9b1..8f4771b5b 100644
--- a/src/chains-config/assetHubKusamaControllers.ts
+++ b/src/chains-config/assetHubKusamaControllers.ts
@@ -72,6 +72,7 @@ export const assetHubKusamaControllers: ControllerConfig = {
 		'RcPalletsStakingValidators',
 		'RcPalletsStakingProgress',
 		'RcPalletsStorage',
+		'RcRuntimeApis',
 		'RcRuntimeCode',
 		'RcRuntimeMetadata',
 		'RcRuntimeSpec',
@@ -82,6 +83,7 @@ export const assetHubKusamaControllers: ControllerConfig = {
 		'RcTransactionFeeEstimate',
 		'RcTransactionMaterial',
 		'RcTransactionSubmit',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/assetHubNextWestendControllers.ts b/src/chains-config/assetHubNextWestendControllers.ts
index 2c004023a..5de054ee0 100644
--- a/src/chains-config/assetHubNextWestendControllers.ts
+++ b/src/chains-config/assetHubNextWestendControllers.ts
@@ -70,6 +70,7 @@ export const assetHubNextWestendControllers: ControllerConfig = {
 		'RcPalletsStakingProgress',
 		'RcPalletsStakingValidators',
 		'RcPalletsStorage',
+		'RcRuntimeApis',
 		'RcRuntimeCode',
 		'RcRuntimeMetadata',
 		'RcRuntimeSpec',
@@ -80,6 +81,7 @@ export const assetHubNextWestendControllers: ControllerConfig = {
 		'RcTransactionFeeEstimate',
 		'RcTransactionMaterial',
 		'RcTransactionSubmit',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/assetHubPolkadotControllers.ts b/src/chains-config/assetHubPolkadotControllers.ts
index cd1eecd1f..9e9705616 100644
--- a/src/chains-config/assetHubPolkadotControllers.ts
+++ b/src/chains-config/assetHubPolkadotControllers.ts
@@ -72,6 +72,7 @@ export const assetHubPolkadotControllers: ControllerConfig = {
 		'RcPalletsStakingValidators',
 		'RcPalletsStakingProgress',
 		'RcPalletsStorage',
+		'RcRuntimeApis',
 		'RcRuntimeCode',
 		'RcRuntimeMetadata',
 		'RcRuntimeSpec',
@@ -82,6 +83,7 @@ export const assetHubPolkadotControllers: ControllerConfig = {
 		'RcTransactionFeeEstimate',
 		'RcTransactionMaterial',
 		'RcTransactionSubmit',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/assetHubWestendControllers.ts b/src/chains-config/assetHubWestendControllers.ts
index 34687a47a..dcf7c5917 100644
--- a/src/chains-config/assetHubWestendControllers.ts
+++ b/src/chains-config/assetHubWestendControllers.ts
@@ -71,6 +71,7 @@ export const assetHubWestendControllers: ControllerConfig = {
 		'RcPalletsStakingValidators',
 		'RcPalletsStakingProgress',
 		'RcPalletsStorage',
+		'RcRuntimeApis',
 		'RcRuntimeCode',
 		'RcRuntimeMetadata',
 		'RcRuntimeSpec',
@@ -81,6 +82,7 @@ export const assetHubWestendControllers: ControllerConfig = {
 		'RcTransactionFeeEstimate',
 		'RcTransactionMaterial',
 		'RcTransactionSubmit',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/astarControllers.ts b/src/chains-config/astarControllers.ts
index a6b10e6ed..9b5e0dbe8 100644
--- a/src/chains-config/astarControllers.ts
+++ b/src/chains-config/astarControllers.ts
@@ -35,6 +35,7 @@ export const astarControllers: ControllerConfig = {
 		'PalletsAssets',
 		'PalletsErrors',
 		'PalletsStorage',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/bifrostControllers.ts b/src/chains-config/bifrostControllers.ts
index 039d34497..28482a096 100644
--- a/src/chains-config/bifrostControllers.ts
+++ b/src/chains-config/bifrostControllers.ts
@@ -31,6 +31,7 @@ export const bifrostControllers: ControllerConfig = {
 		'NodeTransactionPool',
 		'NodeVersion',
 		'PalletsStorage',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/bifrostPolkadotControllers.ts b/src/chains-config/bifrostPolkadotControllers.ts
index c5e7fa826..03c7d032c 100644
--- a/src/chains-config/bifrostPolkadotControllers.ts
+++ b/src/chains-config/bifrostPolkadotControllers.ts
@@ -31,6 +31,7 @@ export const bifrostPolkadotControllers: ControllerConfig = {
 		'NodeTransactionPool',
 		'NodeVersion',
 		'PalletsStorage',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/calamariControllers.ts b/src/chains-config/calamariControllers.ts
index 1fe619f80..64cc53097 100644
--- a/src/chains-config/calamariControllers.ts
+++ b/src/chains-config/calamariControllers.ts
@@ -35,6 +35,7 @@ export const calamariControllers: ControllerConfig = {
 		'NodeVersion',
 		'PalletsStakingProgress',
 		'PalletsStorage',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/coretimeControllers.ts b/src/chains-config/coretimeControllers.ts
index 80686b497..fb8cebb0c 100644
--- a/src/chains-config/coretimeControllers.ts
+++ b/src/chains-config/coretimeControllers.ts
@@ -27,6 +27,7 @@ export const coretimeControllers: ControllerConfig = {
 		'BlocksRawExtrinsics',
 		'NodeNetwork',
 		'NodeVersion',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/crustControllers.ts b/src/chains-config/crustControllers.ts
index 5bc51a340..a71cf0e21 100644
--- a/src/chains-config/crustControllers.ts
+++ b/src/chains-config/crustControllers.ts
@@ -31,6 +31,7 @@ export const crustControllers: ControllerConfig = {
 		'NodeTransactionPool',
 		'NodeVersion',
 		'PalletsStorage',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/defaultControllers.ts b/src/chains-config/defaultControllers.ts
index 705a1146c..20412d41c 100644
--- a/src/chains-config/defaultControllers.ts
+++ b/src/chains-config/defaultControllers.ts
@@ -48,6 +48,7 @@ export const defaultControllers: ControllerConfig = {
 		'PalletsStakingProgress',
 		'PalletsStorage',
 		'Paras',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/dockMainnetControllers.ts b/src/chains-config/dockMainnetControllers.ts
index 2ee022906..7e8295f25 100644
--- a/src/chains-config/dockMainnetControllers.ts
+++ b/src/chains-config/dockMainnetControllers.ts
@@ -31,6 +31,7 @@ export const dockMainnetControllers: ControllerConfig = {
 		'NodeTransactionPool',
 		'NodeVersion',
 		'PalletsStorage',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/dockPoSMainnetControllers.ts b/src/chains-config/dockPoSMainnetControllers.ts
index 7c610a0d2..90d7c27b4 100644
--- a/src/chains-config/dockPoSMainnetControllers.ts
+++ b/src/chains-config/dockPoSMainnetControllers.ts
@@ -34,6 +34,7 @@ export const dockPoSMainnetControllers: ControllerConfig = {
 		'NodeVersion',
 		'PalletsStakingProgress',
 		'PalletsStorage',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/dockPoSTestnetControllers.ts b/src/chains-config/dockPoSTestnetControllers.ts
index 8c1f7e46a..e9fd5f8d4 100644
--- a/src/chains-config/dockPoSTestnetControllers.ts
+++ b/src/chains-config/dockPoSTestnetControllers.ts
@@ -34,6 +34,7 @@ export const dockTestnetControllers: ControllerConfig = {
 		'NodeVersion',
 		'PalletsStakingProgress',
 		'PalletsStorage',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/heikoControllers.ts b/src/chains-config/heikoControllers.ts
index c4599346b..fe222978e 100644
--- a/src/chains-config/heikoControllers.ts
+++ b/src/chains-config/heikoControllers.ts
@@ -35,6 +35,7 @@ export const heikoControllers: ControllerConfig = {
 		'PalletsAssets',
 		'PalletsStorage',
 		'Paras',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/karuraControllers.ts b/src/chains-config/karuraControllers.ts
index 668042047..14264a45f 100644
--- a/src/chains-config/karuraControllers.ts
+++ b/src/chains-config/karuraControllers.ts
@@ -31,6 +31,7 @@ export const karuraControllers: ControllerConfig = {
 		'NodeTransactionPool',
 		'NodeVersion',
 		'PalletsStorage',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/kiltControllers.ts b/src/chains-config/kiltControllers.ts
index 787feea20..f45f6bbf1 100644
--- a/src/chains-config/kiltControllers.ts
+++ b/src/chains-config/kiltControllers.ts
@@ -32,6 +32,7 @@ export const kiltControllers: ControllerConfig = {
 		'NodeTransactionPool',
 		'NodeVersion',
 		'PalletsStorage',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeSpec',
 		'RuntimeMetadata',
diff --git a/src/chains-config/kulupuControllers.ts b/src/chains-config/kulupuControllers.ts
index eafaae286..5a60fc900 100644
--- a/src/chains-config/kulupuControllers.ts
+++ b/src/chains-config/kulupuControllers.ts
@@ -28,6 +28,7 @@ export const kulupuControllers: ControllerConfig = {
 		'NodeTransactionPool',
 		'NodeVersion',
 		'PalletsAssets',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/kusamaControllers.ts b/src/chains-config/kusamaControllers.ts
index 1710d922e..f3772d3ca 100644
--- a/src/chains-config/kusamaControllers.ts
+++ b/src/chains-config/kusamaControllers.ts
@@ -50,6 +50,7 @@ export const kusamaControllers: ControllerConfig = {
 		'PalletsStakingValidators',
 		'PalletsStorage',
 		'Paras',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/mandalaControllers.ts b/src/chains-config/mandalaControllers.ts
index 395daaebb..24ed2648a 100644
--- a/src/chains-config/mandalaControllers.ts
+++ b/src/chains-config/mandalaControllers.ts
@@ -36,6 +36,7 @@ export const mandalaControllers: ControllerConfig = {
 		'PalletsStakingProgress',
 		'PalletsStorage',
 		'Paras',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/mantaControllers.ts b/src/chains-config/mantaControllers.ts
index 505df0404..1125d9e3f 100644
--- a/src/chains-config/mantaControllers.ts
+++ b/src/chains-config/mantaControllers.ts
@@ -34,6 +34,7 @@ export const mantaControllers: ControllerConfig = {
 		'NodeVersion',
 		'PalletsStakingProgress',
 		'PalletsStorage',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/parallelControllers.ts b/src/chains-config/parallelControllers.ts
index 68f1d0e48..efa0aa367 100644
--- a/src/chains-config/parallelControllers.ts
+++ b/src/chains-config/parallelControllers.ts
@@ -35,6 +35,7 @@ export const parallelControllers: ControllerConfig = {
 		'PalletsAssets',
 		'PalletsStorage',
 		'Paras',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/polkadotControllers.ts b/src/chains-config/polkadotControllers.ts
index 807d76d2d..333570c6c 100644
--- a/src/chains-config/polkadotControllers.ts
+++ b/src/chains-config/polkadotControllers.ts
@@ -49,6 +49,7 @@ export const polkadotControllers: ControllerConfig = {
 		'PalletsStakingValidators',
 		'PalletsStorage',
 		'Paras',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/polymeshControllers.ts b/src/chains-config/polymeshControllers.ts
index d6b217028..2f0db3c77 100644
--- a/src/chains-config/polymeshControllers.ts
+++ b/src/chains-config/polymeshControllers.ts
@@ -42,6 +42,7 @@ export const polymeshControllers: ControllerConfig = {
 		'PalletsStakingProgress',
 		'PalletsStakingValidators',
 		'PalletsStorage',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/shidenControllers.ts b/src/chains-config/shidenControllers.ts
index 42ec916f5..9130742e7 100644
--- a/src/chains-config/shidenControllers.ts
+++ b/src/chains-config/shidenControllers.ts
@@ -35,6 +35,7 @@ export const shidenControllers: ControllerConfig = {
 		'PalletsAssets',
 		'PalletsStorage',
 		'Paras',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/soraControllers.ts b/src/chains-config/soraControllers.ts
index 719b71d7d..1f7261ad3 100644
--- a/src/chains-config/soraControllers.ts
+++ b/src/chains-config/soraControllers.ts
@@ -36,6 +36,7 @@ export const soraControllers: ControllerConfig = {
 		'PalletsStakingProgress',
 		'PalletsStorage',
 		'Paras',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/chains-config/westendControllers.ts b/src/chains-config/westendControllers.ts
index 40cc08527..7f5440059 100644
--- a/src/chains-config/westendControllers.ts
+++ b/src/chains-config/westendControllers.ts
@@ -49,6 +49,7 @@ export const westendControllers: ControllerConfig = {
 		'PalletsStakingValidators',
 		'PalletsStorage',
 		'Paras',
+		'RuntimeApis',
 		'RuntimeCode',
 		'RuntimeMetadata',
 		'RuntimeSpec',
diff --git a/src/controllers/index.ts b/src/controllers/index.ts
index c1a12d41a..a9ab52b21 100644
--- a/src/controllers/index.ts
+++ b/src/controllers/index.ts
@@ -73,14 +73,14 @@ import {
 	RcPalletsStakingValidators,
 	RcPalletsStorage,
 } from './rc/pallets';
-import { RcRuntimeCode, RcRuntimeMetadata, RcRuntimeSpec } from './rc/runtime';
+import { RcRuntimeApis, RcRuntimeCode, RcRuntimeMetadata, RcRuntimeSpec } from './rc/runtime';
 import {
 	RcTransactionDryRun,
 	RcTransactionFeeEstimate,
 	RcTransactionMaterial,
 	RcTransactionSubmit,
 } from './rc/transaction';
-import { RuntimeCode, RuntimeMetadata, RuntimeSpec } from './runtime';
+import { RuntimeApis, RuntimeCode, RuntimeMetadata, RuntimeSpec } from './runtime';
 import {
 	TransactionDryRun,
 	TransactionFeeEstimate,
@@ -144,6 +144,7 @@ export const controllers = {
 	RcPalletsStakingProgress,
 	RcPalletsStakingValidators,
 	RcPalletsStorage,
+	RcRuntimeApis,
 	RcRuntimeCode,
 	RcRuntimeMetadata,
 	RcRuntimeSpec,
@@ -154,6 +155,7 @@ export const controllers = {
 	RcTransactionFeeEstimate,
 	RcTransactionMaterial,
 	RcTransactionSubmit,
+	RuntimeApis,
 	RuntimeCode,
 	RuntimeMetadata,
 	RuntimeSpec,
diff --git a/src/controllers/rc/runtime/RcRuntimeApisController.ts b/src/controllers/rc/runtime/RcRuntimeApisController.ts
new file mode 100644
index 000000000..06f6196f5
--- /dev/null
+++ b/src/controllers/rc/runtime/RcRuntimeApisController.ts
@@ -0,0 +1,95 @@
+// Copyright 2017-2026 Parity Technologies (UK) Ltd.
+// This file is part of Substrate API Sidecar.
+//
+// Substrate API Sidecar is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import { RequestHandler } from 'express';
+
+import { ApiPromiseRegistry } from '../../../apiRegistry';
+import { RuntimeApisService } from '../../../services';
+import { IRuntimeApiCallBody, IRuntimeApiMethodParam, IRuntimeApiParam } from '../../../types/requests';
+import AbstractController from '../../AbstractController';
+
+/**
+ * Relay chain runtime API discovery and invocation endpoints.
+ */
+export default class RcRuntimeApisController extends AbstractController<RuntimeApisService> {
+	static controllerName = 'RcRuntimeApis';
+	static requiredPallets = [];
+
+	constructor(_api: string) {
+		const rcApiSpecName = ApiPromiseRegistry.getSpecNameByType('relay')?.values();
+		const rcSpecName = rcApiSpecName ? Array.from(rcApiSpecName)[0] : undefined;
+		if (!rcSpecName) {
+			throw new Error('Relay chain API spec name is not defined.');
+		}
+
+		super(rcSpecName, '/rc/runtime/apis', new RuntimeApisService(rcSpecName));
+		this.initRoutes();
+	}
+
+	protected initRoutes(): void {
+		this.safeMountAsyncGetHandlers([
+			['', this.getRuntimeApis],
+			['/:apiId', this.getRuntimeApi],
+		]);
+
+		this.safeMountAsyncPostHandlers([['/:apiId/:methodId', this.callRuntimeApiMethod]]);
+	}
+
+	private getRuntimeApis: RequestHandler = async ({ query: { at } }, res): Promise<void> => {
+		const rcApi = ApiPromiseRegistry.getApiByType('relay')[0]?.api;
+
+		if (!rcApi) {
+			throw new Error('Relay chain API not found, please use SAS_SUBSTRATE_MULTI_CHAIN_URL env variable');
+		}
+
+		const hash = await this.getHashFromAt(at, { api: rcApi });
+		const apiAt = at ? await rcApi.at(hash) : rcApi;
+
+		RcRuntimeApisController.sanitizedSend(res, await this.service.fetchRuntimeApis(hash, apiAt));
+	};
+
+	private getRuntimeApi: RequestHandler = async ({ params, query: { at } }, res): Promise<void> => {
+		const { apiId } = params as IRuntimeApiParam;
+		const rcApi = ApiPromiseRegistry.getApiByType('relay')[0]?.api;
+
+		if (!rcApi) {
+			throw new Error('Relay chain API not found, please use SAS_SUBSTRATE_MULTI_CHAIN_URL env variable');
+		}
+
+		const hash = await this.getHashFromAt(at, { api: rcApi });
+		const apiAt = at ? await rcApi.at(hash) : rcApi;
+
+		RcRuntimeApisController.sanitizedSend(res, await this.service.fetchRuntimeApi(hash, apiId, apiAt));
+	};
+
+	private callRuntimeApiMethod: RequestHandler = async ({ params, body }, res): Promise<void> => {
+		const { apiId, methodId } = params as IRuntimeApiMethodParam;
+		const { params: runtimeParams, at } = (body ?? {}) as IRuntimeApiCallBody;
+		const rcApi = ApiPromiseRegistry.getApiByType('relay')[0]?.api;
+
+		if (!rcApi) {
+			throw new Error('Relay chain API not found, please use SAS_SUBSTRATE_MULTI_CHAIN_URL env variable');
+		}
+
+		const hash = await this.getHashFromAt(at, { api: rcApi });
+		const apiAt = at ? await rcApi.at(hash) : rcApi;
+
+		RcRuntimeApisController.sanitizedSend(
+			res,
+			await this.service.callRuntimeApi(hash, apiId, methodId, runtimeParams, apiAt),
+		);
+	};
+}
diff --git a/src/controllers/rc/runtime/index.ts b/src/controllers/rc/runtime/index.ts
index 0f912efb9..5721abb0d 100644
--- a/src/controllers/rc/runtime/index.ts
+++ b/src/controllers/rc/runtime/index.ts
@@ -14,6 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+export { default as RcRuntimeApis } from './RcRuntimeApisController';
 export { default as RcRuntimeCode } from './RcRuntimeCodeController';
 export { default as RcRuntimeMetadata } from './RcRuntimeMetadataController';
 export { default as RcRuntimeSpec } from './RcRuntimeSpecController';
diff --git a/src/controllers/runtime/RuntimeApisController.ts b/src/controllers/runtime/RuntimeApisController.ts
new file mode 100644
index 000000000..7c6ebd1b8
--- /dev/null
+++ b/src/controllers/runtime/RuntimeApisController.ts
@@ -0,0 +1,70 @@
+// Copyright 2017-2026 Parity Technologies (UK) Ltd.
+// This file is part of Substrate API Sidecar.
+//
+// Substrate API Sidecar is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import { RequestHandler } from 'express';
+
+import { RuntimeApisService } from '../../services';
+import { IRuntimeApiCallBody, IRuntimeApiMethodParam, IRuntimeApiParam } from '../../types/requests';
+import AbstractController from '../AbstractController';
+
+/**
+ * Runtime API discovery and invocation endpoints.
+ */
+export default class RuntimeApisController extends AbstractController<RuntimeApisService> {
+	static controllerName = 'RuntimeApis';
+	static requiredPallets = [];
+
+	constructor(api: string) {
+		super(api, '/runtime/apis', new RuntimeApisService(api));
+		this.initRoutes();
+	}
+
+	protected initRoutes(): void {
+		this.safeMountAsyncGetHandlers([
+			['', this.getRuntimeApis],
+			['/:apiId', this.getRuntimeApi],
+		]);
+
+		this.safeMountAsyncPostHandlers([['/:apiId/:methodId', this.callRuntimeApiMethod]]);
+	}
+
+	private getRuntimeApis: RequestHandler = async ({ query: { at } }, res): Promise<void> => {
+		const hash = await this.getHashFromAt(at);
+		const apiAt = at ? await this.api.at(hash) : this.api;
+
+		RuntimeApisController.sanitizedSend(res, await this.service.fetchRuntimeApis(hash, apiAt));
+	};
+
+	private getRuntimeApi: RequestHandler = async ({ params, query: { at } }, res): Promise<void> => {
+		const { apiId } = params as IRuntimeApiParam;
+		const hash = await this.getHashFromAt(at);
+		const apiAt = at ? await this.api.at(hash) : this.api;
+
+		RuntimeApisController.sanitizedSend(res, await this.service.fetchRuntimeApi(hash, apiId, apiAt));
+	};
+
+	private callRuntimeApiMethod: RequestHandler = async ({ params, body }, res): Promise<void> => {
+		const { apiId, methodId } = params as IRuntimeApiMethodParam;
+		const { params: runtimeParams, at } = (body ?? {}) as IRuntimeApiCallBody;
+		const hash = await this.getHashFromAt(at);
+		const apiAt = at ? await this.api.at(hash) : this.api;
+
+		RuntimeApisController.sanitizedSend(
+			res,
+			await this.service.callRuntimeApi(hash, apiId, methodId, runtimeParams, apiAt),
+		);
+	};
+}
diff --git a/src/controllers/runtime/index.ts b/src/controllers/runtime/index.ts
index 718b654f8..a38e62a1e 100644
--- a/src/controllers/runtime/index.ts
+++ b/src/controllers/runtime/index.ts
@@ -14,6 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+export { default as RuntimeApis } from './RuntimeApisController';
 export { default as RuntimeCode } from './RuntimeCodeController';
 export { default as RuntimeMetadata } from './RuntimeMetadataController';
 export { default as RuntimeSpec } from './RuntimeSpecController';
diff --git a/src/services/runtime/RuntimeApisService.spec.ts b/src/services/runtime/RuntimeApisService.spec.ts
new file mode 100644
index 000000000..adbff58aa
--- /dev/null
+++ b/src/services/runtime/RuntimeApisService.spec.ts
@@ -0,0 +1,238 @@
+// Copyright 2017-2026 Parity Technologies (UK) Ltd.
+// This file is part of Substrate API Sidecar.
+//
+// Substrate API Sidecar is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import { ApiPromiseRegistry } from '../../apiRegistry';
+import { blockHash789629, defaultMockApi } from '../test-helpers/mock';
+import { RuntimeApisService } from './RuntimeApisService';
+
+const runtimeApisService = new RuntimeApisService('mock');
+const queryInfoMock = jest.fn().mockResolvedValue({
+	toJSON: () => ({ partialFee: '123' }),
+});
+
+const runtimeApiAtMock = {
+	registry: {
+		metadata: {
+			apis: {
+				toArray: () => [
+					{
+						name: {
+							toString: () => 'TransactionPaymentApi',
+						},
+						docs: {
+							toArray: () => [
+								{
+									toString: () => 'Transaction payment runtime API',
+								},
+							],
+						},
+						methods: [
+							{
+								name: {
+									toString: () => 'query_info',
+								},
+								docs: {
+									toArray: () => [
+										{
+											toString: () => 'Query transaction fee info',
+										},
+									],
+								},
+								inputs: [
+									{
+										name: {
+											toString: () => 'uxt',
+										},
+										type: {
+											toString: () => '0',
+										},
+									},
+									{
+										name: {
+											toString: () => 'len',
+										},
+										type: {
+											toString: () => '1',
+										},
+									},
+									{
+										name: {
+											toString: () => 'auth_type',
+										},
+										type: {
+											toString: () => '3',
+										},
+									},
+								],
+								output: {
+									toString: () => '2',
+								},
+							},
+						],
+					},
+				],
+			},
+		},
+		lookup: {
+			getTypeDef: (lookupId: number) => ({
+				lookupName:
+					lookupId === 0
+						? 'Bytes'
+						: lookupId === 1
+							? 'u32'
+							: lookupId === 2
+								? 'RuntimeDispatchInfo'
+								: 'Option<AuthorizationType>',
+				type:
+					lookupId === 0
+						? 'Bytes'
+						: lookupId === 1
+							? 'u32'
+							: lookupId === 2
+								? 'RuntimeDispatchInfo'
+								: 'Option<AuthorizationType>',
+			}),
+		},
+	},
+	call: {
+		transactionPaymentApi: {
+			queryInfo: queryInfoMock,
+		},
+	},
+};
+
+describe('RuntimeApisService', () => {
+	beforeAll(() => {
+		jest.spyOn(ApiPromiseRegistry, 'getApi').mockImplementation(() => defaultMockApi);
+	});
+
+	beforeEach(() => {
+		queryInfoMock.mockClear();
+	});
+
+	it('fetchRuntimeApis should return runtime API summaries', async () => {
+		const result = await runtimeApisService.fetchRuntimeApis(blockHash789629, runtimeApiAtMock as never);
+
+		expect(result.at.hash).toEqual(blockHash789629);
+		expect(result.at.height).toEqual('789629');
+		expect(result.apis.length).toBeGreaterThan(0);
+		expect(result.apis[0].id).toEqual('transactionPaymentApi');
+	});
+
+	it('fetchRuntimeApi should resolve runtime APIs by name or id', async () => {
+		const byId = await runtimeApisService.fetchRuntimeApi(
+			blockHash789629,
+			'transactionPaymentApi',
+			runtimeApiAtMock as never,
+		);
+		const byName = await runtimeApisService.fetchRuntimeApi(
+			blockHash789629,
+			'TransactionPaymentApi',
+			runtimeApiAtMock as never,
+		);
+
+		expect(byId.api.id).toEqual('transactionPaymentApi');
+		expect(byName.api.name).toEqual('TransactionPaymentApi');
+	});
+
+	it('callRuntimeApi should invoke a callable runtime API method', async () => {
+		const result = await runtimeApisService.callRuntimeApi(
+			blockHash789629,
+			'transactionPaymentApi',
+			'queryInfo',
+			{ arg0: '0x00', arg1: 1 },
+			runtimeApiAtMock as never,
+		);
+
+		expect(result.api.id).toEqual('transactionPaymentApi');
+		expect(result.method.id).toEqual('queryInfo');
+		expect(result.result).toEqual({ partialFee: '123' });
+		expect(queryInfoMock).toHaveBeenCalledTimes(1);
+		expect(queryInfoMock).toHaveBeenCalledWith('0x00', 1, null);
+	});
+
+	it('callRuntimeApi should allow omitted Option<T> parameters', async () => {
+		await runtimeApisService.callRuntimeApi(
+			blockHash789629,
+			'transactionPaymentApi',
+			'queryInfo',
+			{ arg0: '0x00', arg1: 1 },
+			runtimeApiAtMock as never,
+		);
+
+		expect(queryInfoMock).toHaveBeenLastCalledWith('0x00', 1, null);
+	});
+
+	it('callRuntimeApi should allow explicit null for Option<T> parameters', async () => {
+		await runtimeApisService.callRuntimeApi(
+			blockHash789629,
+			'transactionPaymentApi',
+			'queryInfo',
+			{ arg0: '0x00', arg1: 1, authType: null },
+			runtimeApiAtMock as never,
+		);
+
+		expect(queryInfoMock).toHaveBeenLastCalledWith('0x00', 1, null);
+	});
+
+	it('callRuntimeApi should reject unknown runtime API names', async () => {
+		await expect(
+			runtimeApisService.callRuntimeApi(
+				blockHash789629,
+				'notRealRuntimeApi',
+				'anyMethod',
+				{},
+				runtimeApiAtMock as never,
+			),
+		).rejects.toThrow("Runtime API 'notRealRuntimeApi' not found.");
+	});
+
+	it('callRuntimeApi should reject unknown method names', async () => {
+		await expect(
+			runtimeApisService.callRuntimeApi(
+				blockHash789629,
+				'transactionPaymentApi',
+				'notRealMethod',
+				{},
+				runtimeApiAtMock as never,
+			),
+		).rejects.toThrow("Runtime API method 'notRealMethod' not found");
+	});
+
+	it('callRuntimeApi should validate missing parameters', async () => {
+		await expect(
+			runtimeApisService.callRuntimeApi(
+				blockHash789629,
+				'transactionPaymentApi',
+				'queryInfo',
+				{ arg0: '0x00' },
+				runtimeApiAtMock as never,
+			),
+		).rejects.toThrow('Missing parameter');
+	});
+
+	it('callRuntimeApi should validate unknown parameter keys', async () => {
+		await expect(
+			runtimeApisService.callRuntimeApi(
+				blockHash789629,
+				'transactionPaymentApi',
+				'queryInfo',
+				{ arg0: '0x00', arg1: 1, extra: 'unexpected' },
+				runtimeApiAtMock as never,
+			),
+		).rejects.toThrow('Unknown parameter keys');
+	});
+});
diff --git a/src/services/runtime/RuntimeApisService.ts b/src/services/runtime/RuntimeApisService.ts
new file mode 100644
index 000000000..02a5b5c34
--- /dev/null
+++ b/src/services/runtime/RuntimeApisService.ts
@@ -0,0 +1,331 @@
+// Copyright 2017-2026 Parity Technologies (UK) Ltd.
+// This file is part of Substrate API Sidecar.
+//
+// Substrate API Sidecar is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import { ApiPromise } from '@polkadot/api';
+import { ApiDecoration } from '@polkadot/api/types';
+import type { BlockHash, ItemDeprecationInfoV16 } from '@polkadot/types/interfaces';
+import { stringCamelCase } from '@polkadot/util';
+import { BadRequest } from 'http-errors';
+
+import {
+	IDeprecationInfo,
+	IRuntimeApi,
+	IRuntimeApiCall,
+	IRuntimeApiDescription,
+	IRuntimeApiMethod,
+	IRuntimeApis,
+} from '../../types/responses';
+import { AbstractService } from '../AbstractService';
+
+type RuntimeQueryableApi = ApiPromise | ApiDecoration<'promise'>;
+type RegistryRuntimeApiMetadata = ReturnType<ApiPromise['registry']['metadata']['apis']['toArray']>[number];
+type RegistryRuntimeApiMethodMetadata = RegistryRuntimeApiMetadata['methods'][number];
+type RegistryRuntimeApiMethodInputMetadata = RegistryRuntimeApiMethodMetadata['inputs'][number];
+
+export class RuntimeApisService extends AbstractService {
+	async fetchRuntimeApis(hash: BlockHash, apiAt?: RuntimeQueryableApi): Promise<IRuntimeApis> {
+		const api = apiAt || this.api;
+		const runtimeApis = this.extractRuntimeApis(api);
+		return {
+			at: await this.getAt(hash),
+			apis: runtimeApis.map((runtimeApi) => ({
+				name: runtimeApi.name,
+				id: runtimeApi.id,
+				docs: runtimeApi.docs,
+				methodCount: runtimeApi.methods.length,
+				methods: runtimeApi.methods.map((method) => ({
+					name: method.name,
+					id: method.id,
+				})),
+			})),
+		};
+	}
+
+	async fetchRuntimeApi(hash: BlockHash, apiId: string, apiAt?: RuntimeQueryableApi): Promise<IRuntimeApi> {
+		const api = apiAt || this.api;
+		const runtimeApis = this.extractRuntimeApis(api);
+		const runtimeApi = this.resolveRuntimeApi(runtimeApis, apiId);
+
+		return {
+			at: await this.getAt(hash),
+			api: runtimeApi,
+		};
+	}
+
+	async callRuntimeApi(
+		hash: BlockHash,
+		apiId: string,
+		methodId: string,
+		params: unknown,
+		apiAt?: RuntimeQueryableApi,
+	): Promise<IRuntimeApiCall> {
+		const api = apiAt || this.api;
+		const runtimeApis = this.extractRuntimeApis(api);
+		const runtimeApi = this.resolveRuntimeApi(runtimeApis, apiId);
+		const runtimeMethod = this.resolveRuntimeMethod(runtimeApi, methodId);
+		const orderedParams = this.orderMethodParams(runtimeMethod, params);
+
+		const callApi = api.call;
+		const runtimeCallApi = callApi[runtimeApi.id];
+
+		if (!runtimeCallApi) {
+			throw new BadRequest(
+				`Runtime API '${runtimeApi.name}' exists in metadata but is not callable via api.call.${runtimeApi.id}.`,
+			);
+		}
+
+		const runtimeCallMethod = runtimeCallApi[runtimeMethod.id];
+
+		if (!runtimeCallMethod) {
+			throw new BadRequest(
+				`Runtime API method '${runtimeMethod.name}' exists in metadata but is not callable via api.call.${runtimeApi.id}.${runtimeMethod.id}.`,
+			);
+		}
+
+		const result = await runtimeCallMethod(...orderedParams);
+
+		return {
+			at: await this.getAt(hash),
+			api: {
+				name: runtimeApi.name,
+				id: runtimeApi.id,
+			},
+			method: {
+				name: runtimeMethod.name,
+				id: runtimeMethod.id,
+			},
+			result: result.toJSON(),
+		};
+	}
+
+	private extractRuntimeApis(api: RuntimeQueryableApi): IRuntimeApiDescription[] {
+		const runtimeApis = api.registry.metadata.apis.toArray();
+
+		if (runtimeApis.length === 0) {
+			throw new BadRequest('Runtime API metadata is not available. This endpoint requires metadata v15 or higher.');
+		}
+
+		return runtimeApis.map((runtimeApi) => this.mapRuntimeApi(api, runtimeApi));
+	}
+
+	private mapRuntimeApi(api: RuntimeQueryableApi, runtimeApi: RegistryRuntimeApiMetadata): IRuntimeApiDescription {
+		const runtimeApiName = runtimeApi.name.toString();
+		const runtimeApiId = stringCamelCase(runtimeApiName);
+		const version = 'version' in runtimeApi ? runtimeApi.version.toNumber() : null;
+		const deprecationInfo =
+			'deprecationInfo' in runtimeApi ? this.mapDeprecationInfo(runtimeApi.deprecationInfo) : null;
+
+		return {
+			name: runtimeApiName,
+			id: runtimeApiId,
+			docs: this.sanitizeMetadataDocs(runtimeApi.docs),
+			version,
+			deprecationInfo,
+			methods: runtimeApi.methods.map((method) => this.mapRuntimeApiMethod(api, method)),
+		};
+	}
+
+	private mapRuntimeApiMethod(api: RuntimeQueryableApi, method: RegistryRuntimeApiMethodMetadata): IRuntimeApiMethod {
+		const methodName = method.name.toString();
+		const methodId = stringCamelCase(methodName);
+		const outputTypeId = method.output.toString();
+		const deprecationInfo = 'deprecationInfo' in method ? this.mapDeprecationInfo(method.deprecationInfo) : null;
+
+		return {
+			name: methodName,
+			id: methodId,
+			docs: this.sanitizeMetadataDocs(method.docs),
+			inputs: method.inputs.map((input, index) => this.mapRuntimeApiMethodInput(api, input, index)),
+			output: {
+				typeId: outputTypeId,
+				type: this.resolveLookupType(api, outputTypeId),
+			},
+			deprecationInfo,
+		};
+	}
+
+	private mapRuntimeApiMethodInput(
+		api: RuntimeQueryableApi,
+		input: RegistryRuntimeApiMethodInputMetadata,
+		index: number,
+	): IRuntimeApiMethod['inputs'][number] {
+		const inputName = input.name.toString() || `arg${index}`;
+		const inputTypeId = input.type.toString();
+
+		return {
+			name: inputName,
+			id: stringCamelCase(inputName),
+			typeId: inputTypeId,
+			type: this.resolveLookupType(api, inputTypeId),
+		};
+	}
+
+	private resolveRuntimeApi(runtimeApis: IRuntimeApiDescription[], apiId: string): IRuntimeApiDescription {
+		const normalizedApiId = apiId.toLowerCase();
+		const runtimeApi = runtimeApis.find(
+			(api) => api.id.toLowerCase() === normalizedApiId || api.name.toLowerCase() === normalizedApiId,
+		);
+
+		if (!runtimeApi) {
+			throw new BadRequest(`Runtime API '${apiId}' not found.`);
+		}
+
+		return runtimeApi;
+	}
+
+	private resolveRuntimeMethod(runtimeApi: IRuntimeApiDescription, methodId: string): IRuntimeApiMethod {
+		const normalizedMethodId = methodId.toLowerCase();
+		const runtimeMethod = runtimeApi.methods.find(
+			(method) => method.id.toLowerCase() === normalizedMethodId || method.name.toLowerCase() === normalizedMethodId,
+		);
+
+		if (!runtimeMethod) {
+			throw new BadRequest(`Runtime API method '${methodId}' not found in '${runtimeApi.name}'.`);
+		}
+
+		return runtimeMethod;
+	}
+
+	private orderMethodParams(runtimeMethod: IRuntimeApiMethod, params: unknown): unknown[] {
+		const paramsObj = this.parseParamsObject(params);
+		const entries = Object.entries(paramsObj);
+		const providedParams = new Map<string, unknown>();
+
+		for (const [key, value] of entries) {
+			providedParams.set(this.normalizeParamKey(key), value);
+		}
+
+		if (!runtimeMethod.inputs.length) {
+			if (entries.length) {
+				throw new BadRequest(
+					`Runtime API method '${runtimeMethod.name}' does not take parameters, but ${entries.length.toString()} were provided.`,
+				);
+			}
+
+			return [];
+		}
+
+		const consumed = new Set<string>();
+		const ordered = runtimeMethod.inputs.map((input, index) => {
+			const acceptedInputKeys = [input.name, input.id, `arg${index}`];
+			const acceptedKeys = new Set<string>(acceptedInputKeys.map((key) => this.normalizeParamKey(key)));
+
+			for (const acceptedKey of acceptedKeys) {
+				if (providedParams.has(acceptedKey)) {
+					consumed.add(acceptedKey);
+					return providedParams.get(acceptedKey);
+				}
+			}
+
+			if (this.isOptionalRuntimeMethodInput(input)) {
+				return null;
+			}
+
+			throw new BadRequest(
+				`Missing parameter for input '${input.name}' on '${runtimeMethod.name}'. Accepted keys: ${acceptedInputKeys
+					.map((key) => `'${key}'`)
+					.join(', ')}.`,
+			);
+		});
+
+		const unknownKeys = entries
+			.map(([key]) => key)
+			.filter((key) => {
+				return !consumed.has(this.normalizeParamKey(key));
+			});
+
+		if (unknownKeys.length) {
+			throw new BadRequest(`Unknown parameter keys for '${runtimeMethod.name}': ${unknownKeys.join(', ')}.`);
+		}
+
+		return ordered;
+	}
+
+	private parseParamsObject(params: unknown): Record<string, unknown> {
+		if (params === undefined || params === null) {
+			return {};
+		}
+
+		if (typeof params !== 'object' || Array.isArray(params)) {
+			throw new BadRequest('Field `params` must be an object keyed by method argument names.');
+		}
+
+		return params as Record<string, unknown>;
+	}
+
+	private normalizeParamKey(key: string): string {
+		return key.replace(/[^a-zA-Z0-9]/g, '').toLowerCase();
+	}
+
+	private isOptionalRuntimeMethodInput(input: IRuntimeApiMethod['inputs'][number]): boolean {
+		return input.type.startsWith('Option<') || input.type === 'Option';
+	}
+
+	private mapDeprecationInfo(deprecationInfo: ItemDeprecationInfoV16): IDeprecationInfo {
+		if (deprecationInfo.isDeprecated) {
+			const { note, since } = deprecationInfo.asDeprecated;
+			return {
+				type: 'Deprecated',
+				note: note.toString(),
+				since: since.isSome ? since.unwrap().toString() : null,
+			};
+		}
+
+		return {
+			type: deprecationInfo.type,
+			note: null,
+			since: null,
+		};
+	}
+
+	private sanitizeMetadataDocs(docs: { toArray: () => Array<{ toString: () => string }> }): string {
+		const docLines = docs
+			.toArray()
+			.map((doc) => doc.toString())
+			.filter(Boolean);
+
+		if (!docLines.length) {
+			return '';
+		}
+
+		return docLines.join('\n');
+	}
+
+	private resolveLookupType(api: RuntimeQueryableApi, typeId: string): string {
+		const lookupId = Number(typeId);
+
+		if (!Number.isFinite(lookupId)) {
+			return typeId;
+		}
+
+		try {
+			const typeDef = api.registry.lookup.getTypeDef(lookupId);
+
+			return typeDef.type || 'Unknown';
+		} catch {
+			return typeId;
+		}
+	}
+
+	private async getAt(hash: BlockHash) {
+		const { number } = await this.api.rpc.chain.getHeader(hash);
+
+		return {
+			hash,
+			height: number.unwrap().toString(10),
+		};
+	}
+}
diff --git a/src/services/runtime/index.ts b/src/services/runtime/index.ts
index 33e0346db..4c82e7f51 100644
--- a/src/services/runtime/index.ts
+++ b/src/services/runtime/index.ts
@@ -14,6 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+export * from './RuntimeApisService';
 export * from './RuntimeCodeService';
 export * from './RuntimeMetadataService';
 export * from './RuntimeSpecService';
diff --git a/src/types/requests.ts b/src/types/requests.ts
index 154361c0a..25591955e 100644
--- a/src/types/requests.ts
+++ b/src/types/requests.ts
@@ -128,6 +128,19 @@ export interface IContractQueryParam extends Query {
 	storageDepositLimit: string;
 }
 
+export interface IRuntimeApiCallBody {
+	params?: Record<string, unknown>;
+	at?: string;
+}
+
+export interface IRuntimeApiParam extends ParamsDictionary {
+	apiId: string;
+}
+
+export interface IRuntimeApiMethodParam extends IRuntimeApiParam {
+	methodId: string;
+}
+
 export interface IPalletsConstantsParam extends ParamsDictionary {
 	palletId: string;
 	constantItemId: string;
diff --git a/src/types/responses/RuntimeApi.ts b/src/types/responses/RuntimeApi.ts
new file mode 100644
index 000000000..c6375a0ac
--- /dev/null
+++ b/src/types/responses/RuntimeApi.ts
@@ -0,0 +1,87 @@
+// Copyright 2017-2026 Parity Technologies (UK) Ltd.
+// This file is part of Substrate API Sidecar.
+//
+// Substrate API Sidecar is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import { IAt } from './At';
+
+export interface IDeprecationInfo {
+	type: 'NotDeprecated' | 'DeprecatedWithoutNote' | 'Deprecated';
+	note: string | null;
+	since: string | null;
+}
+
+interface IRuntimeApiMethodInput {
+	name: string;
+	id: string;
+	typeId: string;
+	type: string;
+}
+
+interface IRuntimeApiMethodOutput {
+	typeId: string;
+	type: string;
+}
+
+export interface IRuntimeApiMethod {
+	name: string;
+	id: string;
+	docs: string;
+	inputs: IRuntimeApiMethodInput[];
+	output: IRuntimeApiMethodOutput;
+	deprecationInfo: IDeprecationInfo | null;
+}
+
+export interface IRuntimeApiDescription {
+	name: string;
+	id: string;
+	docs: string;
+	version: number | null;
+	deprecationInfo: IDeprecationInfo | null;
+	methods: IRuntimeApiMethod[];
+}
+
+interface IRuntimeApiSummary {
+	name: string;
+	id: string;
+	docs: string;
+	methodCount: number;
+	methods: {
+		name: string;
+		id: string;
+	}[];
+}
+
+export interface IRuntimeApis {
+	at: IAt;
+	apis: IRuntimeApiSummary[];
+}
+
+export interface IRuntimeApi {
+	at: IAt;
+	api: IRuntimeApiDescription;
+}
+
+export interface IRuntimeApiCall {
+	at: IAt;
+	api: {
+		name: string;
+		id: string;
+	};
+	method: {
+		name: string;
+		id: string;
+	};
+	result: unknown;
+}
diff --git a/src/types/responses/index.ts b/src/types/responses/index.ts
index f71c29a7c..823870eda 100644
--- a/src/types/responses/index.ts
+++ b/src/types/responses/index.ts
@@ -58,6 +58,7 @@ export * from './Paras';
 export * from './Payout';
 export * from './PoolAssets';
 export * from './RcBlockFormat';
+export * from './RuntimeApi';
 export * from './RuntimeSpec';
 export * from './SanitizedArgs';
 export * from './SanitizedCall';