Release Notes v0.2

Overview

This release introduces the ERC-20 API Server as a new service and includes significant improvements to the Relayer.

New: ERC-20 API Server

A new JSON-RPC 2.0 API server providing ERC-20-like interface for Canton-based tokens.

Features

• Token Metadata Methods (public):

  • erc20_name - Get token name
  • erc20_symbol - Get token symbol
  • erc20_decimals - Get token decimals
  • erc20_totalSupply - Get total supply from cache

• Authenticated Methods (require JWT or EVM signature):

  • erc20_balanceOf - Get user balance
  • erc20_transfer - Transfer tokens between registered users
  • user_register - Register new user with EVM signature

Architecture

• Issuer-centric model: All users share the relayer party, differentiated by fingerprint mapping
• Balance caching system: PostgreSQL-backed cache with periodic reconciliation
• Whitelist support: Address-based registration whitelist
• Graceful shutdown: Configurable timeout with proper cleanup

Configuration

New configuration file: config.api-server.docker.yaml

Relayer Improvements (since v0.1.7)

Features

• Issuer-centric model support - Aligns with API Server architecture
• Docker local testing setup - Full end-to-end testing with auto package ID detection
• Docker build and release workflow - Automated GHCR publishing
• JWT renewal for Canton streamer - Automatic token refresh
• Bridge activity sorting - Events ordered newest to oldest
• Deposit idempotency - Prevents duplicate deposits

Fixes

• Withdrawal balance cache - Now correctly uses EVM address
• Package ID extraction - Updated for v2 packages
• Fingerprint lookups - Fixed cache updates
• Transfer pattern - Uses Burn+Mint instead of non-existent Transfer choice
• DepositReceipt tracking - Properly tracked in raw events
• Healthcheck - Uses GET instead of HEAD
• Streamer error handling - Fixed lastOffset usage and error responses

Maintenance

• Updated canton-erc20 submodule to v2 with renamed packages
• Removed legacy Canton bridge methods
• Dynamic DAR discovery with version 1.0.2 support
• Eliminated DAR build warnings
• Cleaned up deprecated test scripts
• Simplified .dockerignore

Breaking Changes

• Package IDs updated for refactored Daml packages (v2)
• Removed legacy Canton bridge methods - use new API patterns

Upgrade Notes

1. Update configuration files with new package IDs
2. Rebuild DAR files with updated canton-erc20 submodule
3. Run database migrations for API Server balance cache tables
4. Configure relayer_party for issuer-centric model

Docker Images

# Relayer
docker pull ghcr.io/chainsafe/canton-middleware:v0.2

# API Server
docker pull ghcr.io/chainsafe/canton-erc20-api:v0.2

Canton-Ethereum Token Bridge - Release Notes v1.0

Overview

A centralized token bridge connecting CIP-56 tokens on Canton Network with ERC-20 tokens on Ethereum Mainnet, enabling bidirectional cross-chain transfers.

Core Features

Relayer Service

• Go-based relayer node running as a sidecar to Canton Network Partner Node
• Bidirectional event streaming from both Canton and Ethereum
• Persistent offset tracking with PostgreSQL for crash recovery
• Automatic reconciliation of pending transfers (every 5 minutes)
• Readiness probes for Kubernetes deployment

Deposit Flow (EVM → Canton)

• Monitors Deposit events on Ethereum bridge contract
• Creates PendingDeposit on Canton via Ledger API
• Resolves user fingerprint mapping and processes deposit
• Unlocks/mints tokens to Canton user's holding

Withdrawal Flow (Canton → EVM)

• Streams WithdrawalEvent contracts from Canton
• Submits withdrawFromCanton transaction on Ethereum
• Marks withdrawal complete on Canton for reconciliation
• Idempotency protection via Canton tx hash tracking

Smart Contracts

• Ethereum: Solidity bridge contract for ERC-20 lock/unlock and wrapped token mint/burn
• Canton: DAML contracts for CIP-56 token management and bridge operations

Operational Scripts

• bootstrap-bridge.go - Initialize Canton bridge contracts
• register-user.go - Register user fingerprint mappings
• query-holdings.go - Query Canton token holdings
• initiate-withdrawal.go - Initiate Canton→EVM withdrawals
• cleanup-withdrawals.go - Reconcile incomplete withdrawals

Configuration

• YAML-based configuration with environment variable overrides
• Support for local, devnet, and mainnet environments
• Docker Compose deployments included

Observability

• Prometheus metrics for pending transfers
• Structured logging with zap
• Health/readiness endpoints