Solana Mobile Wallet Adapter 2.0.3 plugin for Godot 4 on Android

Connect Solana wallets from any Godot 4 Android game — one plugin, full MWA 2.0.3 coverage.

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Auth Token Cache

Invoke SDK includes an encrypted auth token cache so users only see the wallet approval popup on first launch. Subsequent launches reconnect silently.

Three storage backends are available:

Backend	Best For
keystore	Production — hardware-backed encryption via Android TEE
file	Emulators / devices without full Keystore support
memory	Development — clears on every app close, forces full re-auth

📚 Full Auth Cache documentation →

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What Is This?

Godot 4 has no native Solana integration. If you want your Android game or app to connect to Phantom, Solflare, or Jupiter, you're on your own — until now.

Invoke SDK is a drop-in Android plugin for Godot 4 that exposes the full Solana Mobile Wallet Adapter 2.0.3 API to GDScript via signals and method calls. It handles everything in Kotlin — auth tokens, session caching, transaction building, RPC calls — so your GDScript stays clean.

One .aar file. One signal interface. Full MWA 2.0.3 coverage.

🌐 Website — Landing page 📚 Full Documentation — Getting Started, API Reference, Auth Cache, Wallet Compatibility

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Demo

▶ Watch the full demo on YouTube

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Screenshots

Splash	Dashboard	Sign Transaction

Sign & Send	Sign Message	Capabilities

Auth Cache	Settings	Wallet Connected

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Features

Native Android Plugin	Encrypted Token Cache	Full MWA API
Kotlin bridge, zero JNI boilerplate	AES256-GCM, silent reconnect in 30 min	Every MWA 2.0.3 method exposed to GDScript

Feature	Status
authorize — connect wallet, get auth token	✅
reauthorize — refresh existing session	✅
deauthorize — end session	✅
signTransactions — sign raw transactions	✅
signAndSendTransactions — sign + broadcast to network	✅
signMessages — off-chain message signing	✅
getCapabilities — query wallet feature support	✅
getInstalledWallets — detect installed wallets	✅
Silent reconnect — reuse cached token (< 30 min)	✅
Auto reauth — wallet picker for stale sessions (< 24h)	✅
Instant disconnect — no wallet popup	✅
Encrypted auth token cache (AES256-GCM at rest)	✅
Real memo transactions — no dummy data	✅
Network-aware RPC (Devnet / Testnet / Mainnet)	✅
Full example app — InvokeQuest	✅

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Wallet Compatibility

Tested on Samsung Galaxy Android 14, March 2026:

Wallet	authorize	signTx	signAndSend	signMessage	Notes
Solflare	✅	✅	✅	✅	Best for testing
Jupiter	✅	✅	✅	✅
Phantom	❌	—	—	—	Domain not verified
Backpack	❌	—	—	—	MWA 2.0 incompatible

MWA always opens the system wallet picker on every sign operation — this is by design, not a bug.

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Quick Start

1. Copy the AAR

cp InvokeMWA.aar YOUR_PROJECT/addons/mobile_wallet_adapter/android/InvokeMWA.aar

2. Enable the plugin

In Godot editor: Project → Export → Android → Plugins → InvokeMWA ✅

3. Connect in GDScript

var _mwa = null

func _ready() -> void:
    if Engine.has_singleton("InvokeMWA"):
        _mwa = Engine.get_singleton("InvokeMWA")
        _mwa.authorized.connect(_on_authorized)
        _mwa.mwa_error.connect(_on_mwa_error)

func connect_wallet() -> void:
    _mwa.authorize("solana:devnet", "My Game", "https://mygame.dev", "https://mygame.dev/icon.png")

func _on_authorized(auth_token: String, wallet_address: String) -> void:
    print("Connected: ", wallet_address)

func _on_mwa_error(code: int, message: String) -> void:
    print("Error %d: %s" % [code, message])

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Full API Reference

Signals

Signal	Arguments	Description
authorized	auth_token: String, address: String	Wallet connected, new session
reauthorized	auth_token: String	Session refreshed
deauthorized	—	Session ended
transaction_signed	signatures: Array[String]	Transactions signed (bytes)
transaction_sent	signatures: Array[String]	Transactions broadcast
message_signed	signatures: Array[String]	Messages signed
capabilities_received	json: String	Wallet capabilities JSON
wallet_apps_detected	json: String	Installed wallets JSON
mwa_error	code: int, message: String	Error with code

Methods

Authorization

# Connect wallet — opens system wallet picker
_mwa.authorize(cluster: String, name: String, uri: String, icon: String)

# Refresh session with existing auth token
_mwa.reauthorize(auth_token: String, name: String, uri: String, icon: String)

# End session
_mwa.deauthorize(auth_token: String)

# Silent reconnect — reads auth token from cache automatically
_mwa.tryReauthorizeFromCache(name: String, uri: String, icon: String)

# Instant disconnect — clears cache, no wallet popup
_mwa.disconnectWallet()

Signing

# Sign one or more raw transactions (Base64 encoded)
_mwa.signTransactions(transactions: Array[String])

# Sign and broadcast transactions
_mwa.signAndSendTransactions(transactions: Array[String], min_context_slot: int)

# Sign arbitrary messages off-chain
_mwa.signMessages(messages: Array[String], addresses: Array[String])

Convenience Methods (no auth token needed in GDScript)

# Build and sign a memo transaction — returns signed bytes via transaction_signed
_mwa.signMemoTransaction(memo: String, rpc_url: String)

# Build, sign and broadcast a memo transaction — returns signature via transaction_sent
_mwa.signAndSendMemoTransaction(memo: String, rpc_url: String)

# Sign a text message — returns signature via message_signed
_mwa.signMemoMessage(message: String)

Discovery

# Query wallet for supported MWA features and limits
_mwa.getCapabilities()

# Detect installed MWA-compatible wallets
_mwa.getInstalledWallets()

Cache Inspection

_mwa.cacheHasToken()       # → bool
_mwa.cacheGetAddress()     # → String
_mwa.cacheGetAgeSeconds()  # → int
_mwa.cacheIsStale()        # → bool  (true if > 30 min)
_mwa.cacheClear()          # clear active wallet token
_mwa.cacheClearAll()       # clear all wallet tokens

Error Codes

Code	Constant	Description
1001	USER_DECLINED	User rejected the wallet request
1002	WALLET_NOT_INSTALLED	No MWA wallet found on device
1003	SESSION_ALREADY_ACTIVE	A session is already in progress
1004	AUTH_TOKEN_INVALID	Cached token rejected by wallet
1005	AUTH_TOKEN_EXPIRED	Token too old, re-auth required
2001	TRANSACTION_EXPIRED	Transaction blockhash expired
2002	TRANSACTION_FAILED	Transaction rejected by network
2003	SIMULATION_FAILED	Transaction simulation failed
2004	INSUFFICIENT_FUNDS	Wallet has insufficient SOL
2005	BLOCKHASH_NOT_FOUND	RPC blockhash fetch failed
3001	NETWORK_TIMEOUT	Network request timed out
3002	RPC_ERROR	RPC endpoint returned an error
9999	UNKNOWN	Unmapped exception

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Auth Cache — How It Works

The cache eliminates the wallet approval popup on repeat opens. Invoke SDK uses a three-tier strategy:

App opens → tryReauthorizeFromCache()
  │
  ├─ Token age < 30 min  → Silent reconnect. No wallet interaction. ✅
  │
  ├─ Token age < 24 hrs  → Reauthorize. Wallet picker appears once. ✅
  │
  └─ Token age > 24 hrs  → Session expired. Full authorize required.

Auth tokens are stored in EncryptedSharedPreferences (AES256-GCM key + AES256-SIV value). Tokens are never logged and never exposed to GDScript — all cache reads happen in Kotlin.

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Example App — InvokeQuest

The repo includes InvokeQuest, a full example Android app that demonstrates every SDK method. Find it at example/invokequest/. It is a complete Godot 4 project with all screens, autoloads, and the compiled plugin — ready to build and run on any Android device.

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Project Structure

invoke-solana-sdk/
│
├── android/
│   └── plugin/src/main/kotlin/com/invoke/mwa/
│       ├── MWABridge.kt       ← All wallet logic, transaction building, RPC calls
│       ├── MWAPlugin.kt       ← Godot plugin registration, @UsedByGodot methods
│       ├── AuthCacheImpl.kt   ← EncryptedSharedPreferences token cache
│       └── MWAError.kt        ← Error codes and exception mapper
│
├── example/invokequest/
│   ├── scenes/screens/        ← All GDScript screens
│   ├── autoloads/
│   │   ├── DesignTokens.gd    ← Colors, animation constants
│   │   └── SceneManager.gd    ← Push/pop scene navigation
│   └── addons/mobile_wallet_adapter/
│       └── android/InvokeMWA.aar  ← Compiled plugin
│
└── docs/                      ← Docusaurus documentation site

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Known Limitations

• Clone Authorization — supports_clone_authorization is in the MWA 2.0.3 spec and the SDK queries it correctly via getCapabilities(). Solflare and Jupiter return false — wallet adoption is incomplete. This is expected and will work automatically once wallets ship support. Use cases when available: multi-device gaming, game + companion app sharing one session, multiple SDKs sharing one authorization.
• Backpack — MWA 2.0 incompatible, not supported
• Phantom — Rejects unverified dApp domains (register at developer.phantom.app)
• Silent reconnect — Only within 30-minute window; stale sessions trigger wallet picker
• Solscan devnet — Solscan dropped devnet support; transaction links only work on Testnet and Mainnet
• Wallet picker on every sign — MWA protocol requirement, not a bug

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Troubleshooting

Engine.has_singleton("InvokeMWA") returns false The plugin is not loaded. Verify InvokeMWA.aar is in addons/mobile_wallet_adapter/android/ and the plugin is enabled in Export settings. Check AndroidManifest.xml for org.godotengine.plugin.v2.InvokeMWA.

Wallet picker appears on every app open Expected after 30 minutes. Use tryReauthorizeFromCache() on app start to silently restore sessions within the window.

AUTH_TOKEN_INVALID (code 1004) after reinstall The cached token is stale. Call cacheClearAll() once after reinstall, then re-authorize.

WALLET_NOT_INSTALLED (code 1002) No MWA-compatible wallet installed. Install Solflare or Jupiter.

Transaction broadcast fails with INSUFFICIENT_FUNDS Fund your devnet wallet at faucet.solana.com.

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Building from Source

Prerequisites: JDK 17, Android SDK, Godot 4.2.2, Python 3.x

# 1. Build the AAR
cd android
.\gradlew.bat :plugin:assembleRelease

# 2. Copy AAR to plugin location
Copy-Item "plugin\build\outputs\aar\plugin-release.aar" "..\example\invokequest\addons\mobile_wallet_adapter\android\InvokeMWA.aar" -Force

# 3. Build APK
cd ..\example\invokequest\android\build
.\gradlew.bat assembleRelease

See CONTRIBUTING.md for the full build pipeline, signing setup, and scene asset workflow.

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Trademark Notice

Solana, the Solana logo, Phantom, Solflare, Jupiter, Backpack, and Godot Engine are trademarks or registered trademarks of their respective owners. This project is an independent open-source SDK and is not affiliated with, endorsed by, or sponsored by Solana Foundation, Phantom, Solflare, Jupiter, or the Godot Engine project.

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License

MIT — see LICENSE

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Built for the Solana Mobile ecosystem · Open Source · MIT License

Solflare · Jupiter · Godot 4 · Android 14 · MWA 2.0.3