🌐 GridLink Node

Share your bandwidth. Earn USDC. Run a real DePIN node from your pocket.

GridLink is a decentralized physical infrastructure network (DePIN) that turns Android devices into bandwidth-sharing nodes. Earn micropayments for every megabyte you route, settled on-chain via Solana Testnet.

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🚀 Quick Start

Prerequisites

Tool	Version
Android Studio	Hedgehog+
JDK	17
Python	3.10+
ADB	Latest

Build & Run

# Android app
cd tether
./gradlew assembleDebug
adb install app/build/outputs/apk/debug/app-debug.apk

# FastAPI Matchmaker Oracle
pip install fastapi uvicorn pydantic
uvicorn main:app --host 0.0.0.0 --port 8000

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📱 App Screens

Screen	What It Does
Dashboard	Live bandwidth dial, USDC earnings counter, recent traffic feed
Wallet	Embedded Ed25519 keystore, SOL balance, airdrop, withdraw/stake with Explorer links
Network	Globe visualization, active peers, latency, signal quality
Settings	Private key export, data limits, background service toggle
Invite	Referral QR code generation & sharing

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⚙️ Core Mechanics

┌─────────────┐      HTTP Proxy       ┌──────────────────┐
│  Internet    │◄────────────────────► │  LocalProxyServer │
│  Traffic     │      Port 8080        │  (Netty)          │
└─────────────┘                        └────────┬─────────┘
                                                │
                                       BandwidthTracker
                                                │
                                    ┌───────────▼──────────┐
                                    │   Room DB (SQLite)    │
                                    │  • NodeStats (agg)    │
                                    │  • TrafficLog (feed)  │
                                    └───────────┬──────────┘
                                                │
                                        StateFlow → UI
                                                │
                              ┌─────────────────▼────────────────┐
                              │        Jetpack Compose UI         │
                              │  Dashboard • Wallet • Network     │
                              └──────────────────────────────────┘

• TetherNodeService — Foreground service managing the proxy and bandwidth tracking
• BandwidthTracker — Monitors bytes routed, calculates USDC earnings at $0.003/MB
• Room DB — Persists aggregate stats (NodeStats) and per-session traffic logs (TrafficLog)
• FastAPI Matchmaker — Lightweight oracle for node registration and network status polling

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🔐 Solana Integration

Component	Details
Keypair	Ed25519 via BouncyCastle, stored in EncryptedSharedPreferences
Encoding	Native Base58 encode/decode (no external lib)
RPC Client	OkHttp direct JSON-RPC to api.testnet.solana.com
Airdrop	1 SOL Testnet faucet via requestAirdrop RPC
Balance	Live on-chain balance via getBalance RPC
Settlement	Real SOL transfer: binary tx serialization → Ed25519 sign → sendTransaction RPC → Explorer link
Key Backup	Persistent modal dialog — user must acknowledge before proceeding

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📂 Project Structure

monolith/
├── main.py                          # FastAPI Matchmaker Oracle
├── README.md
└── tether/                          # Android App
    ├── build.gradle.kts
    └── app/src/main/java/com/tether/depin/
        ├── MainActivity.kt
        ├── TetherApplication.kt
        ├── data/
        │   ├── local/
        │   │   ├── AppDatabase.kt       # Room DB definition
        │   │   ├── NodeStats.kt         # Aggregate bandwidth entity
        │   │   ├── NodeStatsDao.kt
        │   │   ├── TrafficLog.kt        # Per-session traffic entity
        │   │   └── TrafficLogDao.kt
        │   ├── remote/
        │   │   ├── ApiClient.kt         # Retrofit + OkHttp setup
        │   │   └── MatchmakerApi.kt     # /node/register, /node/status
        │   └── repository/
        │       └── NodeRepository.kt    # Data layer coordinator
        ├── service/
        │   ├── BandwidthTracker.kt      # Bytes → USDC conversion
        │   ├── LocalProxyServer.kt      # HTTP proxy on :8080
        │   └── TetherNodeService.kt     # Foreground service
        ├── wallet/
        │   ├── WalletConnectionManager.kt  # Singleton Ed25519 keystore
        │   ├── SolanaRpcClient.kt          # Native Testnet JSON-RPC
        │   └── SolanaTransactionBuilder.kt # Real binary TX serialization + Ed25519 signing
        ├── ui/
        │   ├── components/
        │   │   └── BottomNavBar.kt
        │   ├── navigation/
        │   │   └── TetherNavGraph.kt
        │   ├── screens/
        │   │   ├── DashboardScreen.kt
        │   │   ├── WalletScreen.kt
        │   │   ├── WalletOnboardingScreen.kt
        │   │   ├── NetworkScreen.kt
        │   │   ├── SettingsScreen.kt
        │   │   └── InviteScreen.kt
        │   ├── viewmodel/
        │   │   ├── DashboardViewModel.kt
        │   │   ├── WalletViewModel.kt
        │   │   ├── NetworkViewModel.kt
        │   │   └── SettingsViewModel.kt
        │   └── theme/
        │       └── TetherTheme.kt
        └── AndroidManifest.xml

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🛠 Tech Stack

Layer	Technology
Language	Kotlin 1.9, Python 3.10
UI Framework	Jetpack Compose (BOM 2024.06) + Material3
Navigation	Compose Navigation 2.7
Database	Room 2.6 (SQLite)
Networking	Retrofit 2.9, OkHttp 4.12, Moshi
Crypto	BouncyCastle Ed25519, EncryptedSharedPreferences
Blockchain	Solana Testnet JSON-RPC, Base58, Ed25519 on-chain signing
Backend	FastAPI + Uvicorn
QR Codes	ZXing 3.5
Permissions	Accompanist 0.34
Location	Google Play Services Location 21.1
Data	DataStore Preferences, Kotlin Coroutines + Flow
Build	Gradle KTS, KSP

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📄 License

MIT Licnse

Built by Danyal — GridLink DePIN, Monolith 2026.