Supported Chains

swapapi supports token swaps on major EVM chains. Pass the chainId as a path parameter to GET /v1/swap/{chainId}.

Chain reference

Chain	Chain ID	Native Token	Native Token Address
Ethereum	1	ETH	0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE
Base	8453	ETH	0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE
Arbitrum One	42161	ETH	0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE
Polygon	137	POL	0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE
Optimism	10	ETH	0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE
Avalanche	43114	AVAX	0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE
BNB Chain	56	BNB	0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE

Native token address

Use 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE as the address for the native gas token on any chain (ETH, POL, AVAX, BNB). This is a universal convention across DeFi protocols.

Example: Swap on each chain

Ethereum (chainId: 1)

curl "https://api.swapapi.dev/v1/swap/1?tokenIn=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE&tokenOut=0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48&amount=1000000000000000000&sender=YOUR_ADDRESS"

Base (chainId: 8453)

curl "https://api.swapapi.dev/v1/swap/8453?tokenIn=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE&tokenOut=0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913&amount=1000000000000000000&sender=YOUR_ADDRESS"

Arbitrum (chainId: 42161)

curl "https://api.swapapi.dev/v1/swap/42161?tokenIn=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE&tokenOut=0xaf88d065e77c8cC2239327C5EDb3A432268e5831&amount=1000000000000000000&sender=YOUR_ADDRESS"

Unsupported chains

If you pass an unsupported chain ID, you'll get a 400 response:

{
  "success": false,
  "error": {
    "code": "UNSUPPORTED_CHAIN",
    "message": "Chain 999 is not supported",
    "details": { "chainId": 999 }
  },
  "timestamp": "2026-03-12T00:00:00.000Z"
}