01
Send a GET request
Pass chain, tokens, amount, and sender address as query params. That's the entire interface — one GET request.
Free Token Swap API
No API keys. No accounts. Returns executable calldata. Built for AI agents and autonomous systems.
bash
$ curl "https://api.swapapi.xyz/v1/swap/1?\ tokenIn=0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE&\ tokenOut=0x6B3595068778DD592e39A122f4f5a5cF09C90fE2&\ amount=1000000000000000000&\ sender=0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
response.json
{ "success": true, "data": { "status": "Successful", "tokenFrom": { "symbol": "ETH", "decimals": 18 }, "tokenTo": { "symbol": "USDC", "decimals": 6 }, "swapPrice": 2500.0, "priceImpact": 0.0012, "amountIn": "1000000000000000000", "expectedAmountOut": "2500000000", "tx": { "to": "0x...router", "data": "0x...calldata", "value": "1000000000000000000", "gas": "250000" } }, "timestamp": "2026-03-12T00:00:00.000Z" }
Try it yourself
How it works
Three steps to a swap
02
We find the best route
Your request is routed across DEX liquidity pools on 46 chains. Best price, lowest slippage, optimized gas.
03
You get calldata back
The response includes a ready-to-sign tx object. Submit it on-chain with any wallet or signer library.
Why this exists
Built for machines, usable by humans
No API keys
Every other swap API requires registration. AI agents can't sign up for accounts. We removed the barrier entirely.
No authentication
No OAuth, no headers, no tokens. A raw HTTP GET is all you need. Works from curl, from code, from an autonomous agent.
Returns calldata
You don't just get a quote — you get a complete transaction object ready to sign and broadcast. No extra steps.
Free forever
We make money on positive slippage, not on you. Your quoted price is our commitment — if we can do better, we keep the difference.
Supported chains
Live on 46 networks
Response format
What you get back
Every response follows the same envelope. Parse success first, then read data.
GET /v1/swap/{chainId} — 200 OK
{ "success": true, // always check this first "data": { "status": "Successful", // "Successful" | "Partial" | "NoRoute" "tokenFrom": { // input token metadata "address": "0xEeee...EEeE", "symbol": "ETH", "name": "Ether", "decimals": 18 }, "tokenTo": { // output token metadata "address": "0xA0b8...eB48", "symbol": "USDC", "name": "USD Coin", "decimals": 6 }, "swapPrice": 2847.53, // exchange rate "priceImpact": 0.0012, // 0.12% — ratio, not percentage "amountIn": "1000000000000000000", // raw amount (BigInt as string) "expectedAmountOut": "284753...", // raw expected output "tx": { // ready-to-sign transaction "from": "0xd8dA...6045", // your sender address "to": "0x...router", // router contract "data": "0x...calldata", // encoded swap calldata "value": "1000000000000000000", // ETH to send (for native swaps) "gas": "250000" // estimated gas limit } }, "timestamp": "2026-03-12T..." // ISO 8601 }
Error response — 400 / 429 / 502
{ "success": false, "error": { "code": "INVALID_PARAMS", // machine-readable error code "message": "Invalid token...", // human-readable description "details": {} // optional additional context }, "timestamp": "2026-03-12T..." }
Query parameters
GET /v1/swap/{chainId} chainId path required Blockchain network ID (46 chains supported) tokenIn query required Input token address (0x...) tokenOut query required Output token address (0x...) amount query required Amount in raw units (no decimals) sender query required Sender address for tx.from maxSlippage query optional Slippage tolerance 0-1 (default: 0.005)