across-protocol Supported Chains and Tokens
This file summarizes chain IDs explicitly enumerated in the Across API schema. The canonical, always-current list is the API itself (see endpoints below).
Mainnet Chains (per API schema)
| Chain | Chain ID |
|---|---|
| Ethereum | 1 |
| Optimism | 10 |
| Polygon | 137 |
| zkSync Era | 324 |
| Base | 8453 |
| Arbitrum | 42161 |
| Linea | 59144 |
Testnet Chains (per API schema)
| Chain | Chain ID |
|---|---|
| Ethereum Sepolia | 11155111 |
| Arbitrum Sepolia | 421614 |
| Base Sepolia | 84532 |
| Optimism Sepolia | 11155420 |
Discovering Tokens and Routes
Supported chains (Swap API)
GET /swap/chains
Returns all chains that support crosschain swaps.
Supported tokens (Swap API)
GET /swap/tokens
Returns all whitelisted tokens across all chains. Tokens must be whitelisted by swap sources to appear here.
Supported sources (Swap API)
GET /swap/sources
GET /swap/sources?chainId={id}
Returns supported swap sources globally or for a specific chain.
Available routes (bridge-only)
GET /available-routes?originChainId={id}&destinationChainId={id}
Returns all supported bridgeable token pairs between two chains, including token symbols and addresses on each chain. This only includes bridgeable tokens.
Common Token Addresses (reference examples)
These are commonly used token addresses for building API calls. Always verify against GET /swap/tokens or GET /available-routes before production use — addresses can change as token contracts are upgraded.
USDC
| Chain | Address |
|---|---|
| Ethereum (1) | 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 |
| Arbitrum (42161) | 0xaf88d065e77c8cC2239327C5EDb3A432268e5831 |
| Base (8453) | 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913 |
| Optimism (10) | 0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85 |
| Polygon (137) | 0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359 |
WETH (use this instead of ETH)
| Chain | Address |
|---|---|
| Ethereum (1) | 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2 |
| Arbitrum (42161) | 0x82aF49447D8a07e3bd95BD0d56f35241523fBab1 |
| Base (8453) | 0x4200000000000000000000000000000000000006 |
| Optimism (10) | 0x4200000000000000000000000000000000000006 |
USDT
| Chain | Address |
|---|---|
| Ethereum (1) | 0xdAC17F958D2ee523a2206206994597C13D831ec7 |
| Arbitrum (42161) | 0xFd086bC7CD5C481DCC9C85ebE478A1C0b69FCbb9 |
DAI
| Chain | Address |
|---|---|
| Ethereum (1) | 0x6B175474E89094C44Da98b954EedeAC495271d0F |
| Arbitrum (42161) | 0xDA10009cBd5D07dd0CeCc66161FC93D7c9000da1 |
| Optimism (10) | 0xDA10009cBd5D07dd0CeCc66161FC93D7c9000da1 |
WBTC
| Chain | Address |
|---|---|
| Ethereum (1) | 0x2260FAC5E5542a773Aa44fBCfeDf7C193bc2C599 |
| Arbitrum (42161) | 0x2f2a2543B76A4166549F7aaB2e75Bef0aefC5B0f |
Token Address Notes
- Always use wrapped native token addresses when querying APIs (WETH, not ETH; WMATIC, not MATIC).
- Token addresses are chain-specific — the same token has different addresses on different chains.
- Amounts are always in the token's native decimals (USDC = 6 decimals, WETH = 18 decimals, DAI = 18 decimals, WBTC = 8 decimals).
- When in doubt, query the API. The addresses above are for reference only.
Contract Addresses
Full contract addresses for all chains (mainnet and testnet) are maintained at: https://docs.across.to/reference/contract-addresses
Notes
- The API is the source of truth for current chain and token support.
- Chain lists expand over time. Use the endpoints above for the latest data.