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POST
/
swap
/
usdc-e
/
submit
Submit USDC → USDC.e swap
curl --request POST \
  --url https://relayer.kuest.com/swap/usdc-e/submit \
  --header 'Content-Type: application/json' \
  --data '
{
  "type": "SAFE",
  "from": "0x0B2B3E6B323C0Cd7bEaf4B7cC73b983D4E9B12c7",
  "to": "0xA238CBeb142c10Ef7Ad8442C6D1f9E89e07e7761",
  "proxyWallet": "0x3f8Be6FC21f4a5127A42CE1aF58d8bCb8A94F3c1",
  "data": "0x8d80ff0a0000000000000000000000000000000000000000000000000000000000000040",
  "nonce": "12",
  "value": "0",
  "signature": "0xf368488355b0566e99eff3bccc35e98b77d8f3a6e6866176188488c34f0305b07e4a4c600c7a1592e4ac1e96b5887ebff2cb26987a3ad501006b39944df098c21f",
  "signatureParams": {
    "operation": "1",
    "safeTxnGas": "0",
    "baseGas": "0",
    "gasPrice": "0",
    "gasToken": "0x0000000000000000000000000000000000000000",
    "refundReceiver": "0x0000000000000000000000000000000000000000"
  },
  "metadata": "swap_usdc_e"
}
'
{
  "txHash": "0x61a1b449f2b534d08a2f807cd5de867f9013e44e2df421a1d8c5b7f467ff3154",
  "confirmations": 1
}
Submit a signed Safe payload from POST /swap/usdc-e/build. The relayer verifies the Safe owner, validates the multisend target, and broadcasts the transaction on-chain.
POST to https://relayer.kuest.com/swap/usdc-e/submit with the standard L2 headers. The payload mirrors POST /submit but is restricted to SAFE operations targeting the Safe multisend contract.

​
Request body

This endpoint accepts the same payload as POST /submit. Use the transaction and nonce from the build response, and copy the build signatureParams into the request.
FieldTypeRequiredDescription
typestringYesMust be SAFE.
fromstringYesSafe owner address (must match KUEST_ADDRESS).
tostringYesMust match the Safe multisend contract returned by the build endpoint.
proxyWalletstringYesSafe proxy executing the swap.
datastringYesMultisend calldata from the build response.
noncestringYesSafe nonce from the build response.
valuestringNoAlways 0.
signaturestringYesPacked Safe signature over the typed data hash.
signatureParamsobjectYesSignature metadata from the build response.
metadatastringNoOptional label (e.g. swap_usdc_e).

​
Usage notes

  • The relayer does not perform a new quote on submit. If the quote is stale, rebuild and sign again.
  • If the Safe nonce is out of sync, the relayer responds with 409 and you must rebuild.

Body

application/json

Signed SAFE payload executed immediately by relayer operations.

​
type
enum<string>
required
Available options:
SAFE
​
from
string
required

Safe owner submitting the request.

​
to
string
required

Contract to execute.

​
proxyWallet
string
required

Existing Safe proxy address.

​
data
string
required
​
nonce
string
required
​
signature
string
required
​
signatureParams
object
required
​
value
string
default:0
​
metadata
string | null

Response

Swap transaction broadcast by the relayer.

​
txHash
string
required
​
confirmations
integer<int32>
required