The Graph GRT Circulation Endpoint

A deterministic L1+L2 GRT supply reconciliation service that provides accurate token circulation data by combining Layer 1 (Ethereum) and Layer 2 network data.

Overview

This service fetches GRT token supply data from both:

• Layer 1: The Graph GRT Supply Subgraph (includes vesting schedules and inflation tracking)
• Layer 2: The Graph Network Subgraph on Arbitrum One (includes bridge transactions and L2 minting)

The reconciliation logic ensures no double-counting while providing comprehensive supply data across both layers.

Features

• 🔄 Deterministic Logic: Requires both L1 and L2 data for accurate results
• ⚡ Parallel Fetching: L1 and L2 data fetched simultaneously for performance
• 🛡️ Robust Error Handling: Exponential backoff with circuit breaker pattern
• 📊 Rich Monitoring: Performance metrics and health endpoints
• ✅ Data Validation: Cross-layer consistency checks
• 🧪 Comprehensive Testing: Unit, integration, and reconciliation tests

API Endpoints

Supply Data (L1+L2 Reconciled)

• GET /token-supply - Returns total supply (L1 + L2 net supply)
• GET /circulating-supply - Returns circulating supply (L1 + L2 net supply)
• GET /global-state - Returns full breakdown with L1/L2 data
• GET /global-state?timestamp=1640995200 - Historical reconciled data

Health & Monitoring

• GET /health/l1 - L1 layer health and circuit breaker status
• GET /health/l2 - L2 layer health and circuit breaker status
• GET /health/combined - Overall system health
• GET /config - Current configuration status
• GET /ping - Basic health check for load balancers

Setup

Prerequisites

• Node.js 18+
• Etherscan API key
• pnpm (preferred) or yarn

Installation

# Install dependencies
pnpm install

# Set up environment variables
cp .env.example .env

Environment Variables

# Required
ETHERSCAN_API_KEY=your_etherscan_api_key
L2_SUBGRAPH_URL=https://gateway.thegraph.com/api/subgraphs/id/DZz4kDTdmzWLWsV373w2bSmoar3umKKH9y82SUKr5qmp

# Optional
PORT=3000
RETRY_MAX_ATTEMPTS=3
RETRY_BASE_DELAY_MS=1000
ENABLE_SUPPLY_VALIDATION=true

Development

# Start development server
pnpm dev

# Run tests
pnpm test
pnpm test:reconciliation
pnpm test:l2

# Build for production
pnpm build
pnpm start

Reconciliation Logic

Data Sources

• L1 GRT Supply Subgraph: totalSupply, circulatingSupply, lockedSupply (includes vesting and inflation)
• L2 Graph Network Subgraph: totalSupply, totalGRTDepositedConfirmed, totalGRTWithdrawn

Bridge Flow Accounting

The key insight is properly handling L1↔L2 bridge flows to avoid double-counting:

// L2 net supply (new tokens minted on L2, accounting for bridge flows)
netL2Supply = L2.totalSupply - (L2.totalGRTDepositedConfirmed - L2.totalGRTWithdrawn)

// Combined totals (avoiding double counting)
totalSupply = L1.totalSupply + netL2Supply
circulatingSupply = L1.circulatingSupply + netL2Supply
lockedSupply = L1.lockedSupply  // L2 deposits are transfers, not locks

Why This Works

• L1→L2 Deposits: Counted in L1 total, subtracted from L2 net to avoid double counting
• L2→L1 Withdrawals: Burned on L2, added back to L2 net calculation for accuracy
• L2 Net Supply: Represents only new tokens minted on L2, not bridged tokens

Example Response

{
  "totalSupply": 10586449198.7,
  "circulatingSupply": 11503848555.1,
  "lockedSupply": 248151617.15,
  "liquidSupply": 10338297581.5,
  "reconciliationTimestamp": 1640995200000,
  "l1Breakdown": {
    "totalSupply": 10472259308.43,
    "circulatingSupply": 8065857537.24,
    "lockedSupply": 248151617.15,
    "liquidSupply": 799107691.27
  },
  "l2Breakdown": {
    "totalSupply": "3344392801699562803941900360",
    "totalGRTDepositedConfirmed": "3230297690874856963763373638",
    "netL2Supply": "114095110824705840178526722"
  }
}

Error Handling

The system uses deterministic error handling:

• All-or-Nothing: Must have both L1 and L2 data to succeed
• Retry Logic: 3 attempts with exponential backoff (1s, 2s, 4s)
• Circuit Breaker: Prevents cascade failures after 5 consecutive failures
• HTTP 503: Returned when either L1 or L2 layer fails

Deployment

Vercel

# Deploy to Vercel
pnpm deploy

# Or configure in vercel.json
{
  "env": {
    "L2_SUBGRAPH_URL": "https://gateway.thegraph.com/api/subgraphs/id/DZz4kDTdmzWLWsV373w2bSmoar3umKKH9y82SUKr5qmp"
  }
}

Docker/Generic

# Build
pnpm build

# Set environment variables
export ETHERSCAN_API_KEY=your_key
export L2_SUBGRAPH_URL=https://gateway.thegraph.com/api/subgraphs/id/DZz4kDTdmzWLWsV373w2bSmoar3umKKH9y82SUKr5qmp

# Start
pnpm start

Monitoring

The service provides detailed metrics:

• L1/L2 fetch times and success rates
• Circuit breaker status per service
• Reconciliation performance metrics
• Cross-layer validation warnings

Monitor the /health/combined endpoint for overall system status.

Architecture

┌─────────────┐    ┌─────────────┐
│   L1 Fetch  │    │   L2 Fetch  │
│ (Parallel)  │    │ (Parallel)  │
└──────┬──────┘    └──────┬──────┘
       │                  │
       ▼                  ▼
┌─────────────────────────────┐
│    Retry Handler with       │
│    Exponential Backoff      │
└────────────┬────────────────┘
             │
             ▼
┌─────────────────────────────┐
│      Data Validation        │
│   (L1, L2, Cross-layer)     │
└────────────┬────────────────┘
             │
             ▼
┌─────────────────────────────┐
│     Supply Reconciler       │
│  totalSupply = L1 + L2Net   │
│ circulatingSupply = L1 + L2 │
└────────────┬────────────────┘
             │
             ▼
┌─────────────────────────────┐
│      API Response           │
│  (Plain text or JSON with   │
│   L1/L2 breakdown)          │
└─────────────────────────────┘

License

This project is licensed under the MIT License.