Gasless Swap (Permit)
Swap tokens without paying gas. Sign off-chain and a relayer submits the transaction for you. Great for fresh wallets or moving funds without needing ETH upfront.
Catalog action EVM Onchain wallet swap
Swap tokens without paying gas. Sign off-chain and a relayer submits the transaction for you. Great for fresh wallets or moving funds without needing ETH upfront.
This action can require a wallet connector, gas, token movement, or an external side effect. Test with simulation or a controlled amount before using it in a live workflow.
At a Glance
| Field | Value |
|---|---|
| Action ID | permit-relayer-swap |
| Category | EVM Onchain |
| Connector | wallet |
| Requires gas | No |
| Funds movement | swap |
| Tags | blockchain, evm, dex, swap, gasless, uniswap, token, trading |
Payload Schema
| Field | Type | Required | Description |
|---|---|---|---|
sellToken | string | Yes | Address of ERC-2612 permit-compatible token to sell (e.g., USDC) |
buyToken | string | Yes | Address of token to buy. Use 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE for native ETH |
sellAmount | string | Yes | Amount of sell token in smallest unit (e.g., USDC has 6 decimals: 1000000 = 1 USDC) |
chainId | number | Yes | Chain ID (1=Ethereum, 42161=Arbitrum, 137=Polygon) |
receiver | string | No | Optional recipient address for the output tokens. Defaults to the user's wallet. |
uniswapFeeTier | number | No | Uniswap V3 pool fee tier in hundredths of a bip (default: 500 = 0.05%) |
Result Schema
| Field | Type | Required | Description |
|---|---|---|---|
status | string | Yes | Status of the swap |
sellToken | string | No | Sell token address |
buyToken | string | No | Buy token address |
sellAmount | string | No | Sell amount in smallest unit |
permitTxHash | string | No | Transaction hash of the permit submission |
swapTxHash | string | No | Transaction hash of the Uniswap swap |
buyAmount | string | No | Amount of buy token received in smallest unit (wei) |
totalGasUsed | string | No | Total gas used across all relayer transactions |
errorCode | string | No | Error code if status is error |
errorMessage | string | No | Error message if status is error |
Examples
json{ "type": "permit-relayer-swap", "payload": { "sellToken": "0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE", "buyToken": "0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE", "sellAmount": "1000000", "chainId": 1 }, "children": [], "connector": { "type": "wallet", "id": "conn_wallet" }}
bashcurl -X POST "https://api.b3os.org/v1/actions/permit-relayer-swap/test" \ -H "Authorization: Bearer YOUR_API_KEY" \ -H "Content-Type: application/json" \ -d '{ "inputs": { "sellToken": "0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE", "buyToken": "0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE", "sellAmount": "1000000", "chainId": 1 }}'
Payload fields can use workflow expressions such as {{$trigger.body.amount}}, {{$nodes.fetch.result.price}}, and {{$props.asset}} when the value should come from a trigger, prior node, or reusable workflow prop.