diff --git a/package.json b/package.json
index 6cd7cb1d..c2882a6d 100644
--- a/package.json
+++ b/package.json
@@ -10,7 +10,7 @@
     "lint:fix": "eslint --fix",
     "test": "npm run test:unit && npm run test:typescript",
     "test:unit": "c8 node --test --test-timeout=30000",
-    "test:typescript": "tsd"
+    "test:typescript": "tstyche"
   },
   "repository": {
     "type": "git",
@@ -72,7 +72,7 @@
     "proxy": "^4.0.0",
     "proxyquire": "^2.1.3",
     "split2": "^4.2.0",
-    "tsd": "^0.33.0"
+    "tstyche": "^7.0.0"
   },
   "dependencies": {
     "@fastify/error": "^4.0.0",
@@ -86,4 +86,4 @@
   "publishConfig": {
     "access": "public"
   }
-}
+}
\ No newline at end of file
diff --git a/types/index.test-d.ts b/types/index.test-d.ts
deleted file mode 100644
index 7458860a..00000000
--- a/types/index.test-d.ts
+++ /dev/null
@@ -1,194 +0,0 @@
-import fastify, { FastifyReply, FastifyRequest, RawServerBase, RequestGenericInterface, RouteGenericInterface } from 'fastify'
-import * as http from 'node:http'
-import { IncomingHttpHeaders } from 'node:http2'
-import * as https from 'node:https'
-import { AddressInfo } from 'node:net'
-import { expectType } from 'tsd'
-import { Agent, Client, Dispatcher, Pool } from 'undici'
-import replyFrom, { FastifyReplyFromOptions, RawServerResponse } from '..'
-// @ts-ignore
-import tap from 'tap'
-
-const fullOptions: FastifyReplyFromOptions = {
-  base: 'http://example2.com',
-  http: {
-    agentOptions: {
-      keepAliveMsecs: 60 * 1000,
-      maxFreeSockets: 2048,
-      maxSockets: 2048
-    },
-    requestOptions: {
-      timeout: 1000
-    },
-    agents: {
-      'http:': new http.Agent({}),
-      'https:': new https.Agent({})
-    }
-  },
-  http2: {
-    sessionTimeout: 1000,
-    requestTimeout: 1000,
-    sessionOptions: {
-      rejectUnauthorized: true
-    },
-    requestOptions: {
-      endStream: true
-    }
-  },
-  cacheURLs: 100,
-  disableCache: false,
-  undici: {
-    connections: 100,
-    pipelining: 10,
-    proxy: 'http://example2.com:8080'
-  },
-  contentTypesToEncode: ['application/x-www-form-urlencoded'],
-  retryMethods: ['GET', 'HEAD', 'OPTIONS', 'TRACE'],
-  maxRetriesOn503: 10,
-  disableRequestLogging: false,
-  globalAgent: false,
-  destroyAgent: true
-}
-
-async function main () {
-  const server = fastify()
-
-  server.register(replyFrom)
-
-  server.register(replyFrom, {})
-
-  server.register(replyFrom, { http2: true })
-
-  server.register(replyFrom, fullOptions)
-
-  server.register(replyFrom, { undici: { proxy: new URL('http://example2.com:8080') } })
-
-  server.register(replyFrom, { undici: { proxy: { uri: 'http://example2.com:8080' } } })
-
-  server.get('/v1', (_request, reply) => {
-    expectType<FastifyReply>(reply.from())
-  })
-  server.get('/v3', (_request, reply) => {
-    reply.from('/v3', {
-      timeout: 1000,
-      body: { hello: 'world' },
-      rewriteRequestHeaders (req, headers) {
-        expectType<FastifyRequest<RequestGenericInterface, RawServerBase>>(req)
-        return headers
-      },
-      getUpstream (req, base) {
-        expectType<FastifyRequest<RequestGenericInterface, RawServerBase>>(req)
-        return base
-      },
-      onResponse (request, reply, res) {
-        expectType<FastifyRequest<RequestGenericInterface, RawServerBase>>(request)
-        expectType<FastifyReply<RouteGenericInterface, RawServerBase>>(reply)
-        expectType<RawServerResponse<RawServerBase>>(res)
-        expectType<number>(res.statusCode)
-      }
-    })
-  })
-
-  // http2
-  const instance = fastify({ http2: true })
-  // @ts-ignore
-  tap.tearDown(instance.close.bind(instance))
-  const target = fastify({ http2: true })
-  // @ts-ignore
-  tap.tearDown(target.close.bind(target))
-  instance.get('/', (_request, reply) => {
-    reply.from()
-  })
-
-  instance.get('/http2', (_request, reply) => {
-    reply.from('/', {
-      method: 'POST',
-      retryDelay: ({ req, res, err, attempt, getDefaultDelay }) => {
-        const defaultDelay = getDefaultDelay(req, res, err, attempt)
-        if (defaultDelay) return defaultDelay
-
-        if (res && res.statusCode === 500 && req.method === 'GET') {
-          return 300
-        }
-        return null
-      },
-      rewriteHeaders (headers) {
-        return headers
-      },
-      rewriteRequestHeaders (_req, headers: IncomingHttpHeaders) {
-        return headers
-      },
-      getUpstream (_req, base) {
-        return base
-      },
-      onError (reply: FastifyReply<RouteGenericInterface, RawServerBase>, error) {
-        return reply.send(error.error)
-      },
-      queryString (search, reqUrl, request) {
-        expectType<string | undefined>(search)
-        expectType<string>(reqUrl)
-        expectType<FastifyRequest<RequestGenericInterface, RawServerBase>>(request)
-        return ''
-      },
-    })
-  })
-
-  await target.listen({ port: 0 })
-  const port = (target.server.address() as AddressInfo).port
-  instance.register(replyFrom, {
-    base: `http://localhost:${port}`,
-    http2: {
-      sessionOptions: {
-        rejectUnauthorized: false,
-      },
-    },
-  })
-  instance.register(replyFrom, {
-    base: `http://localhost:${port}`,
-    http2: true,
-  })
-  await instance.listen({ port: 0 })
-
-  const undiciInstance = fastify()
-  undiciInstance.register(replyFrom, {
-    base: 'http://example2.com',
-    undici: {
-      pipelining: 10,
-      connections: 10
-    }
-  })
-  await undiciInstance.ready()
-
-  const undiciInstanceAgent = fastify()
-  undiciInstance.register(replyFrom, {
-    base: 'http://example2.com',
-    undici: new Agent()
-  })
-  await undiciInstanceAgent.ready()
-
-  const undiciInstancePool = fastify()
-  undiciInstance.register(replyFrom, {
-    base: 'http://example2.com',
-    undici: new Pool('http://example2.com')
-  })
-  await undiciInstancePool.ready()
-
-  const undiciInstanceClient = fastify()
-  undiciInstance.register(replyFrom, {
-    base: 'http://example2.com',
-    undici: new Client('http://example2.com')
-  })
-  await undiciInstanceClient.ready()
-
-  const undiciInstanceDispatcher = fastify()
-  undiciInstance.register(replyFrom, {
-    base: 'http://example2.com',
-    undici: new Dispatcher()
-  })
-  await undiciInstanceDispatcher.ready()
-
-  tap.pass('done')
-  tap.end()
-}
-
-main()
diff --git a/types/index.tst.ts b/types/index.tst.ts
new file mode 100644
index 00000000..5e2bf6f8
--- /dev/null
+++ b/types/index.tst.ts
@@ -0,0 +1,123 @@
+import { expect } from 'tstyche'
+import fastify, {
+  type FastifyReply,
+  type FastifyRequest,
+  type RawServerBase,
+  type RequestGenericInterface,
+  type RouteGenericInterface
+} from 'fastify'
+import * as http from 'node:http'
+import { type IncomingHttpHeaders } from 'node:http2'
+import * as https from 'node:https'
+import { Agent, Client, Dispatcher, Pool } from 'undici'
+import replyFrom, {
+  type FastifyReplyFromOptions,
+  type RawServerResponse
+} from '.'
+
+const fullOptions: FastifyReplyFromOptions = {
+  base: 'http://example2.com',
+  http: {
+    agentOptions: {
+      keepAliveMsecs: 60 * 1000,
+      maxFreeSockets: 2048,
+      maxSockets: 2048
+    },
+    requestOptions: { timeout: 1000 },
+    agents: {
+      'http:': new http.Agent({}),
+      'https:': new https.Agent({})
+    }
+  },
+  http2: {
+    sessionTimeout: 1000,
+    requestTimeout: 1000,
+    sessionOptions: { rejectUnauthorized: true },
+    requestOptions: { endStream: true }
+  },
+  cacheURLs: 100,
+  disableCache: false,
+  undici: {
+    connections: 100,
+    pipelining: 10,
+    proxy: 'http://example2.com:8080'
+  },
+  contentTypesToEncode: ['application/x-www-form-urlencoded'],
+  retryMethods: ['GET', 'HEAD', 'OPTIONS', 'TRACE'],
+  maxRetriesOn503: 10,
+  disableRequestLogging: false,
+  globalAgent: false,
+  destroyAgent: true
+}
+
+const app = fastify()
+
+app.register(replyFrom)
+app.register(replyFrom, {})
+app.register(replyFrom, { http2: true })
+app.register(replyFrom, fullOptions)
+app.register(replyFrom, { undici: { proxy: new URL('http://example2.com:8080') } })
+app.register(replyFrom, { undici: { proxy: { uri: 'http://example2.com:8080' } } })
+
+app.register(replyFrom, { base: 'http://example.com', undici: new Agent() })
+app.register(replyFrom, { base: 'http://example.com', undici: new Pool('http://example.com') })
+app.register(replyFrom, { base: 'http://example.com', undici: new Client('http://example.com') })
+app.register(replyFrom, { base: 'http://example.com', undici: new Dispatcher() })
+
+app.get('/v1', (_request, reply) => {
+  expect(reply.from()).type.toBe<FastifyReply>()
+})
+
+app.get('/v3', (_request, reply) => {
+  reply.from('/v3', {
+    timeout: 1000,
+    body: { hello: 'world' },
+    rewriteRequestHeaders (req, headers) {
+      expect(req).type.toBe<FastifyRequest<RequestGenericInterface, RawServerBase>>()
+      return headers
+    },
+    getUpstream (req, base) {
+      expect(req).type.toBe<FastifyRequest<RequestGenericInterface, RawServerBase>>()
+      return base
+    },
+    onResponse (request, reply, res) {
+      expect(request).type.toBe<FastifyRequest<RequestGenericInterface, RawServerBase>>()
+      expect(reply).type.toBe<FastifyReply<RouteGenericInterface, RawServerBase>>()
+      expect(res).type.toBe<RawServerResponse<RawServerBase>>()
+      expect(res.statusCode).type.toBe<number>()
+    }
+  })
+})
+
+app.get('/http2', (_request, reply) => {
+  reply.from('/', {
+    method: 'POST',
+    retryDelay: ({ req, res, err, attempt, getDefaultDelay }) => {
+      const defaultDelay = getDefaultDelay(req, res, err, attempt)
+      expect(defaultDelay).type.toBe<number | null>()
+
+      if (res && res.statusCode === 500 && req.method === 'GET') {
+        return 300
+      }
+      return null
+    },
+    rewriteHeaders (headers) {
+      return headers
+    },
+    rewriteRequestHeaders (_req, headers: IncomingHttpHeaders) {
+      return headers
+    },
+    onError (reply: FastifyReply<RouteGenericInterface, RawServerBase>, error) {
+      return reply.send(error.error)
+    },
+    queryString (search, reqUrl, request) {
+      expect(search).type.toBe<string | undefined>()
+      expect(reqUrl).type.toBe<string>()
+      expect(request).type.toBe<FastifyRequest<RequestGenericInterface, RawServerBase>>()
+      return ''
+    },
+  })
+})
+
+expect<FastifyReplyFromOptions>().type.toBeAssignableFrom(fullOptions)
+expect<FastifyReplyFromOptions>().type.toBeAssignableFrom({ http2: true })