zkEVM Bridge Service

A robust, high-performance backend service written in Go that enables seamless asset bridging between Ethereum L1 and L2 networks connected to the Agglayer. This service provides the core infrastructure for cross-chain transfers by generating and managing Merkle proofs, monitoring transactions, and handling claim operations.

🌟 Features

• Cross-Chain Asset and Message Transfers: Bridge ERC-20 tokens, ETH and messages between L1 and L2 networks
• Merkle Proof Generation: Automated generation of cryptographic proofs for secure cross-chain claims
• Transaction Monitoring: Real-time monitoring and management of bridge transactions
• Claim Management: Automated and manual claim processing with retry mechanisms
• Multi-Network Support: Support for hundreds of L2 networks simultaneously
• RESTful API: HTTP/gRPC API for integration with frontend applications
• Database Persistence: PostgreSQL/SQLite support for reliable data storage
• Metrics & Monitoring: Prometheus metrics integration for operational visibility
• Auto-Claim Service: Automated claiming for authorized addresses
• Grouping Claims: Transaction batching for gas optimization

🏗️ Architecture

The service consists of several key components:

• Synchronizer: Monitors L1/L2 events and maintains state consistency
• Claim Transaction Manager: Handles claim transaction lifecycle and monitoring
• Bridge Controller: Manages bridge operations and Merkle tree operations
• API Server: Provides REST/gRPC endpoints for client interactions
• Database Layer: Persistent storage for deposits, claims, and metadata

🚀 Quick Start

Prerequisites

• Go 1.24+
• Docker & Docker Compose
• PostgreSQL (or SQLite for development)
• Access to Ethereum L1 and L2 nodes (Erigon or OP-Geth)

Installation

# Clone the repository
git clone https://github.com/0xPolygon/zkevm-bridge-service.git
cd zkevm-bridge-service

# Build the service
make build

# Or build the Docker image
make build-docker

Configuration

1. Copy the example configuration:

cp config/config.local.toml config/config.toml

2. Update the configuration with your network parameters, database details and urls:

[SyncDB]
  Database = "postgres"
  [SyncDB.PgStorage]
    User = "test_user"
    Password = "test_password"
    Name = "test_db"
    Host = "zkevm-bridge-db"
    Port = "5432"
    MaxConns = 20

[BridgeServer]
  [BridgeServer.DB]
    Database = "postgres"
    [BridgeServer.DB.PgStorage]
    User = "test_user"
    Password = "test_password"
    Name = "test_db"
    Host = "zkevm-bridge-db"
    Port = "5432"
    MaxConns = 20

[Etherman]
  L1URL = "http://zkevm-mock-l1-network:8545"
  L2URLs = ["http://zkevm-node:8123"]

[NetworkConfig]
  L1GenBlockNumber = 0
  L2GenBlockNumbers = [0]
  PolygonBridgeAddress = "0xFe12ABaa190Ef0c8638Ee0ba9F828BF41368Ca0E"
  PolygonZkEVMGlobalExitRootAddress = "0x8A791620dd6260079BF849Dc5567aDC3F2FdC318"
  PolygonRollupManagerAddress = "0xB7f8BC63BbcaD18155201308C8f3540b07f84F5e"
  L2ClaimCompressorAddress = "0x2279B7A0a67DB372996a5FaB50D91eAA73d2eBe6"
  L2PolygonBridgeAddresses = ["0xFe12ABaa190Ef0c8638Ee0ba9F828BF41368Ca0E"]
  RequireSovereignChainSmcs = [false]
  L2PolygonZkEVMGlobalExitRootAddresses = ["0xa40d5f56745a118d0906a34e69aec8c0db1cb8fa"]

Running the Service

Using Docker Compose (Recommended)

# Start all services including databases
make run

Manual Execution

# Start the database
make run-db-bridge

# Start the bridge service
./bin/zkevm-bridge run --cfg config/config.toml

📖 Usage

REST API

The service exposes several REST endpoints:

# Get bridge information
GET /api/v1/bridges/{address}

# Get claim merkle proof
GET /merkle-proof?deposit_cnt=1&net_id=0

# Health check
GET /api

## Note: Check the proto file to get all the details (proto/src/proto/bridge/v1/query.proto)

CLI Commands

# Show version
./bin/zkevm-bridge version

# Run the service
./bin/zkevm-bridge run --cfg /app/config.toml

🧪 Testing

Unit Tests

make test

Integration Tests

# Run integration tests
make test-full

E2E Tests for Real Networks

# Build E2E test Docker image
make build-docker-e2e-real_network

# Run tests against real networks
docker run --volume "./config/:/config/" \
  --env BRIDGE_TEST_CONFIG_FILE=/config/test.toml \
  bridge-e2e-realnetwork-erc20

🔧 Development

Project Structure

├── autoclaimservice/    # Standalone automated claim service
├── bridgectrl/          # Bridge controller logic
├── claimtxman/          # Autoclaim transaction management
├── cmd/                 # CLI application entry point
├── config/              # Configuration management
├── db/                  # Database migrations and schemas
├── etherman/            # Ethereum client interactions
├── server/              # HTTP/gRPC API server
├── synchronizer/        # L1/L2 event synchronization
├── test/                # Test suites and utilities
└── utils/               # Common utilities

Building from Source

# Install dependencies
go mod download

# Generate code (protobuf, mocks, etc.)
make generate-code-from-proto generate-mocks

# Build binary
make build

# Build docker image
make build-docker

# Run linting
make lint

# Run Benchmark
make bench bench-full

# Run local environment
make run

# Stop local environment
make stop

## Note: Check the make file to see all the options

📊 Monitoring & Metrics

The service exposes Prometheus metrics on /metrics endpoint:

• Bridge transaction counters
• Processing latency histograms
• Error rates and types
• Database connection metrics
• Node synchronization status

Example metrics:

bridge_deposits_total{network_id="1"}
bridge_claims_total{status="confirmed"}
bridge_processing_duration_seconds

🔐 Security

• All cross-chain transfers are secured by cryptographic Merkle proofs
• Database credentials should be stored securely (use environment variables)
• API endpoints support rate limiting and authentication
• Regular security audits are performed on smart contracts

📚 Documentation

• Local Development Setup
• E2E Testing Guide
• API Reference
• Configuration Guide

🆘 Support

• Documentation: Check our docs directory
• Issues: Report bugs via GitHub Issues
• Discord: Join the Polygon zkEVM Discord for community support
• Forum: Visit the Polygon Community Forum

---

Made with ❤️ by the Polygon team