Layerswap Docs

A gasless deposit asks the user to sign typed authorization data instead of broadcasting the source transaction. A relayer submits the deposit and pays source-network gas; its cost is reflected in the gasless quote.

Check support and pricing

Read supports_gasless_deposit on the relevant network/token data. Pass use_gasless=true to /limits, /quote, or /detailed_quote so the displayed fees and receive amount match the intended funding method.

Create a gasless swap

curl --request POST 'https://api.layerswap.io/api/v2/swaps' \
  --header 'Content-Type: application/json' \
  --header 'X-LS-APIKEY: YOUR_API_KEY' \
  --data '{
    "source_network": "ETHEREUM_MAINNET",
    "source_token": "USDC",
    "destination_network": "ARBITRUM_MAINNET",
    "destination_token": "ETH",
    "destination_address": "0xRecipient",
    "refund_address": "0xSourceNetworkRefundAddress",
    "amount": 100,
    "use_gasless": true
  }'

Fetch and sign the action

Fetch deposit actions with the signer’s address:

curl 'https://api.layerswap.io/api/v2/swaps/SWAP_ID/deposit_actions?source_address=0xSigner' \
  --header 'X-LS-APIKEY: YOUR_API_KEY'

A supported gasless action has type: "sign" and a typed_data EIP-712 payload. Ask the wallet to sign that exact payload:

const action = response.data.deposit_actions.find((item) => item.type === 'sign');

const signature = await window.ethereum.request({
  method: 'eth_signTypedData_v4',
  params: [signerAddress, JSON.stringify(action.typed_data)],
});

Submit the authorization

await fetch(`https://api.layerswap.io/api/v2/swaps/${swapId}/authorize`, {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'X-LS-APIKEY': apiKey,
  },
  body: JSON.stringify({ signature, signer_address: signerAddress }),
});

Use GET /swaps/{id}/authorize to inspect the authorization resource and GET /swaps/{id} to track the swap lifecycle. If the action is unavailable or authorization fails, fall back to another funding method rather than reconstructing typed data yourself.