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POST
/
transactions
/
{chainId}
Build calldata for a Market Swap
curl --request POST \
  --url https://api.velora.xyz/transactions/{chainId} \
  --header 'Content-Type: application/json' \
  --data '
{
  "priceRoute": {
    "blockNumber": 123,
    "network": 1,
    "srcToken": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
    "srcDecimals": 123,
    "srcAmount": "1000000000000000000",
    "destToken": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
    "destDecimals": 123,
    "destAmount": "1000000000000000000",
    "bestRoute": [
      {}
    ],
    "gasCostUSD": "<string>",
    "gasCost": "<string>",
    "version": "<string>",
    "contractAddress": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
    "tokenTransferProxy": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
    "contractMethod": "<string>",
    "partnerFee": 123,
    "srcUSD": "<string>",
    "destUSD": "<string>",
    "partner": "<string>",
    "maxImpactReached": true,
    "hmac": "<string>"
  },
  "srcToken": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
  "destToken": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
  "userAddress": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
  "srcDecimals": 123,
  "destDecimals": 123,
  "srcAmount": "1000000000000000000",
  "destAmount": "1000000000000000000",
  "slippage": 5000,
  "txOrigin": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
  "receiver": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
  "partner": "my-app-name",
  "partnerAddress": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
  "partnerFeeBps": "<string>",
  "permit": "<string>",
  "deadline": 123,
  "isCapSurplus": true,
  "takeSurplus": false,
  "isSurplusToUser": false,
  "isDirectFeeTransfer": false
}
'
import requests

url = "https://api.velora.xyz/transactions/{chainId}"

payload = {
    "priceRoute": {
        "blockNumber": 123,
        "network": 1,
        "srcToken": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
        "srcDecimals": 123,
        "srcAmount": "1000000000000000000",
        "destToken": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
        "destDecimals": 123,
        "destAmount": "1000000000000000000",
        "bestRoute": [{}],
        "gasCostUSD": "<string>",
        "gasCost": "<string>",
        "version": "<string>",
        "contractAddress": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
        "tokenTransferProxy": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
        "contractMethod": "<string>",
        "partnerFee": 123,
        "srcUSD": "<string>",
        "destUSD": "<string>",
        "partner": "<string>",
        "maxImpactReached": True,
        "hmac": "<string>"
    },
    "srcToken": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
    "destToken": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
    "userAddress": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
    "srcDecimals": 123,
    "destDecimals": 123,
    "srcAmount": "1000000000000000000",
    "destAmount": "1000000000000000000",
    "slippage": 5000,
    "txOrigin": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
    "receiver": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
    "partner": "my-app-name",
    "partnerAddress": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
    "partnerFeeBps": "<string>",
    "permit": "<string>",
    "deadline": 123,
    "isCapSurplus": True,
    "takeSurplus": False,
    "isSurplusToUser": False,
    "isDirectFeeTransfer": False
}
headers = {"Content-Type": "application/json"}

response = requests.post(url, json=payload, headers=headers)

print(response.text)
const options = {
  method: 'POST',
  headers: {'Content-Type': 'application/json'},
  body: JSON.stringify({
    priceRoute: {
      blockNumber: 123,
      network: 1,
      srcToken: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
      srcDecimals: 123,
      srcAmount: '1000000000000000000',
      destToken: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
      destDecimals: 123,
      destAmount: '1000000000000000000',
      bestRoute: [{}],
      gasCostUSD: '<string>',
      gasCost: '<string>',
      version: '<string>',
      contractAddress: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
      tokenTransferProxy: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
      contractMethod: '<string>',
      partnerFee: 123,
      srcUSD: '<string>',
      destUSD: '<string>',
      partner: '<string>',
      maxImpactReached: true,
      hmac: '<string>'
    },
    srcToken: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
    destToken: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
    userAddress: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
    srcDecimals: 123,
    destDecimals: 123,
    srcAmount: '1000000000000000000',
    destAmount: '1000000000000000000',
    slippage: 5000,
    txOrigin: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
    receiver: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
    partner: 'my-app-name',
    partnerAddress: '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
    partnerFeeBps: '<string>',
    permit: '<string>',
    deadline: 123,
    isCapSurplus: true,
    takeSurplus: false,
    isSurplusToUser: false,
    isDirectFeeTransfer: false
  })
};

fetch('https://api.velora.xyz/transactions/{chainId}', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));
<?php

$curl = curl_init();

curl_setopt_array($curl, [
  CURLOPT_URL => "https://api.velora.xyz/transactions/{chainId}",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => json_encode([
    'priceRoute' => [
        'blockNumber' => 123,
        'network' => 1,
        'srcToken' => '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
        'srcDecimals' => 123,
        'srcAmount' => '1000000000000000000',
        'destToken' => '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
        'destDecimals' => 123,
        'destAmount' => '1000000000000000000',
        'bestRoute' => [
                [
                                
                ]
        ],
        'gasCostUSD' => '<string>',
        'gasCost' => '<string>',
        'version' => '<string>',
        'contractAddress' => '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
        'tokenTransferProxy' => '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
        'contractMethod' => '<string>',
        'partnerFee' => 123,
        'srcUSD' => '<string>',
        'destUSD' => '<string>',
        'partner' => '<string>',
        'maxImpactReached' => true,
        'hmac' => '<string>'
    ],
    'srcToken' => '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
    'destToken' => '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
    'userAddress' => '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
    'srcDecimals' => 123,
    'destDecimals' => 123,
    'srcAmount' => '1000000000000000000',
    'destAmount' => '1000000000000000000',
    'slippage' => 5000,
    'txOrigin' => '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
    'receiver' => '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
    'partner' => 'my-app-name',
    'partnerAddress' => '0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045',
    'partnerFeeBps' => '<string>',
    'permit' => '<string>',
    'deadline' => 123,
    'isCapSurplus' => true,
    'takeSurplus' => false,
    'isSurplusToUser' => false,
    'isDirectFeeTransfer' => false
  ]),
  CURLOPT_HTTPHEADER => [
    "Content-Type: application/json"
  ],
]);

$response = curl_exec($curl);
$err = curl_error($curl);

curl_close($curl);

if ($err) {
  echo "cURL Error #:" . $err;
} else {
  echo $response;
}
package main

import (
	"fmt"
	"strings"
	"net/http"
	"io"
)

func main() {

	url := "https://api.velora.xyz/transactions/{chainId}"

	payload := strings.NewReader("{\n  \"priceRoute\": {\n    \"blockNumber\": 123,\n    \"network\": 1,\n    \"srcToken\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n    \"srcDecimals\": 123,\n    \"srcAmount\": \"1000000000000000000\",\n    \"destToken\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n    \"destDecimals\": 123,\n    \"destAmount\": \"1000000000000000000\",\n    \"bestRoute\": [\n      {}\n    ],\n    \"gasCostUSD\": \"<string>\",\n    \"gasCost\": \"<string>\",\n    \"version\": \"<string>\",\n    \"contractAddress\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n    \"tokenTransferProxy\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n    \"contractMethod\": \"<string>\",\n    \"partnerFee\": 123,\n    \"srcUSD\": \"<string>\",\n    \"destUSD\": \"<string>\",\n    \"partner\": \"<string>\",\n    \"maxImpactReached\": true,\n    \"hmac\": \"<string>\"\n  },\n  \"srcToken\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"destToken\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"userAddress\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"srcDecimals\": 123,\n  \"destDecimals\": 123,\n  \"srcAmount\": \"1000000000000000000\",\n  \"destAmount\": \"1000000000000000000\",\n  \"slippage\": 5000,\n  \"txOrigin\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"receiver\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"partner\": \"my-app-name\",\n  \"partnerAddress\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"partnerFeeBps\": \"<string>\",\n  \"permit\": \"<string>\",\n  \"deadline\": 123,\n  \"isCapSurplus\": true,\n  \"takeSurplus\": false,\n  \"isSurplusToUser\": false,\n  \"isDirectFeeTransfer\": false\n}")

	req, _ := http.NewRequest("POST", url, payload)

	req.Header.Add("Content-Type", "application/json")

	res, _ := http.DefaultClient.Do(req)

	defer res.Body.Close()
	body, _ := io.ReadAll(res.Body)

	fmt.Println(string(body))

}
HttpResponse<String> response = Unirest.post("https://api.velora.xyz/transactions/{chainId}")
  .header("Content-Type", "application/json")
  .body("{\n  \"priceRoute\": {\n    \"blockNumber\": 123,\n    \"network\": 1,\n    \"srcToken\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n    \"srcDecimals\": 123,\n    \"srcAmount\": \"1000000000000000000\",\n    \"destToken\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n    \"destDecimals\": 123,\n    \"destAmount\": \"1000000000000000000\",\n    \"bestRoute\": [\n      {}\n    ],\n    \"gasCostUSD\": \"<string>\",\n    \"gasCost\": \"<string>\",\n    \"version\": \"<string>\",\n    \"contractAddress\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n    \"tokenTransferProxy\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n    \"contractMethod\": \"<string>\",\n    \"partnerFee\": 123,\n    \"srcUSD\": \"<string>\",\n    \"destUSD\": \"<string>\",\n    \"partner\": \"<string>\",\n    \"maxImpactReached\": true,\n    \"hmac\": \"<string>\"\n  },\n  \"srcToken\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"destToken\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"userAddress\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"srcDecimals\": 123,\n  \"destDecimals\": 123,\n  \"srcAmount\": \"1000000000000000000\",\n  \"destAmount\": \"1000000000000000000\",\n  \"slippage\": 5000,\n  \"txOrigin\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"receiver\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"partner\": \"my-app-name\",\n  \"partnerAddress\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"partnerFeeBps\": \"<string>\",\n  \"permit\": \"<string>\",\n  \"deadline\": 123,\n  \"isCapSurplus\": true,\n  \"takeSurplus\": false,\n  \"isSurplusToUser\": false,\n  \"isDirectFeeTransfer\": false\n}")
  .asString();
require 'uri'
require 'net/http'

url = URI("https://api.velora.xyz/transactions/{chainId}")

http = Net::HTTP.new(url.host, url.port)
http.use_ssl = true

request = Net::HTTP::Post.new(url)
request["Content-Type"] = 'application/json'
request.body = "{\n  \"priceRoute\": {\n    \"blockNumber\": 123,\n    \"network\": 1,\n    \"srcToken\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n    \"srcDecimals\": 123,\n    \"srcAmount\": \"1000000000000000000\",\n    \"destToken\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n    \"destDecimals\": 123,\n    \"destAmount\": \"1000000000000000000\",\n    \"bestRoute\": [\n      {}\n    ],\n    \"gasCostUSD\": \"<string>\",\n    \"gasCost\": \"<string>\",\n    \"version\": \"<string>\",\n    \"contractAddress\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n    \"tokenTransferProxy\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n    \"contractMethod\": \"<string>\",\n    \"partnerFee\": 123,\n    \"srcUSD\": \"<string>\",\n    \"destUSD\": \"<string>\",\n    \"partner\": \"<string>\",\n    \"maxImpactReached\": true,\n    \"hmac\": \"<string>\"\n  },\n  \"srcToken\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"destToken\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"userAddress\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"srcDecimals\": 123,\n  \"destDecimals\": 123,\n  \"srcAmount\": \"1000000000000000000\",\n  \"destAmount\": \"1000000000000000000\",\n  \"slippage\": 5000,\n  \"txOrigin\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"receiver\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"partner\": \"my-app-name\",\n  \"partnerAddress\": \"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045\",\n  \"partnerFeeBps\": \"<string>\",\n  \"permit\": \"<string>\",\n  \"deadline\": 123,\n  \"isCapSurplus\": true,\n  \"takeSurplus\": false,\n  \"isSurplusToUser\": false,\n  \"isDirectFeeTransfer\": false\n}"

response = http.request(request)
puts response.read_body
{
  "from": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
  "to": "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045",
  "value": "0",
  "data": "<string>",
  "gasPrice": "16000000000",
  "maxFeePerGas": "<string>",
  "maxPriorityFeePerGas": "<string>",
  "gas": "<string>",
  "chainId": 1
}
{
  "errorType": "PricingError",
  "details": "Error getting price data"
}
{
  "errorType": "PricingError",
  "details": "Error getting price data"
}

Path Parameters

​
chainId
integer
required

EVM chain ID. Matches priceRoute.network. EVM chain ID. Supported values today include 1 (Mainnet), 10 (Optimism), 56 (BSC), 137 (Polygon), 8453 (Base), 42161 (Arbitrum), 43114 (Avalanche), 100 (Gnosis). The set is open — call GET /chains for the live list.

Example:

1

Query Parameters

​
gasPrice
string

Gas price to use for the transaction, in WEI.

​
ignoreChecks
boolean
default:false

Skip on-chain balance, allowance, and transaction-failure checks. The response omits the gas field when enabled.

​
ignoreGasEstimate
boolean
default:false

Skip the gas estimate. The response omits the gas field when enabled.

​
onlyParams
boolean
default:false

Return only the contract call parameters instead of a full transaction object.

​
eip1559
boolean
default:false

Return an EIP-1559 transaction with maxFeePerGas and maxPriorityFeePerGas in place of gasPrice.

Body

application/json
​
priceRoute
object
required

The priceRoute block returned by GET /prices, passed verbatim — do not recompute or re-encode.

​
srcToken
string
required

Source token address. A token symbol listed in /tokens can be used instead.

Pattern: ^0x[a-fA-F0-9]{40}$
Example:

"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

​
destToken
string
required

Destination token address. A token symbol listed in /tokens can be used instead.

Pattern: ^0x[a-fA-F0-9]{40}$
Example:

"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

​
userAddress
string
required

Address of the transaction caller (msg.sender). When using an intermediary contract, userAddress should correspond to msg.sender and receiver to the recipient.

Pattern: ^0x[a-fA-F0-9]{40}$
Example:

"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

​
srcDecimals
integer

Source token decimals. Can be omitted if a token symbol is used in srcToken.

​
destDecimals
integer

Destination token decimals. Can be omitted if a token symbol is used in destToken.

​
srcAmount
string

Source amount in WEI/raw units. Required when side=SELL. On side=BUY it can be omitted if slippage is provided.

Example:

"1000000000000000000"

​
destAmount
string

Destination amount in WEI/raw units. Required when side=BUY. On side=SELL it can be omitted if slippage is provided.

Example:

"1000000000000000000"

​
slippage
integer

Allowed slippage in basis points (0–10000). 250 = 2.5%. Required when the non-fixed amount (destAmount on SELL, srcAmount on BUY) is omitted.

Required range: 0 <= x <= 10000
​
txOrigin
string

When msg.sender differs from the transaction sender, pass the sender here along with userAddress.

Pattern: ^0x[a-fA-F0-9]{40}$
Example:

"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

​
receiver
string

Recipient of the swap output, for Swap & Transfer. Omit when userAddress receives.

Pattern: ^0x[a-fA-F0-9]{40}$
Example:

"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

​
partner
string

Partner string. Used for analytics and fee attribution on your project's swaps.

Example:

"my-app-name"

​
partnerAddress
string

Address entitled to claim partner fees or surplus.

Pattern: ^0x[a-fA-F0-9]{40}$
Example:

"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

​
partnerFeeBps
string

Partner fee in basis points, used with partnerAddress. 200 = 2%.

​
permit
string

Signed permit payload (hex). Lets the swap skip the separate approve transaction.

​
deadline
integer

Unix timestamp (seconds) after which the transaction is no longer valid.

​
isCapSurplus
boolean
default:true

Cap collected surplus at 1%.

​
takeSurplus
boolean
default:false

Collect positive slippage as surplus. Works with partnerAddress.

​
isSurplusToUser
boolean
default:false

Route positive slippage / surplus to the user instead of the partner.

​
isDirectFeeTransfer
boolean
default:false

Transfer the partner fee directly rather than accruing it in the Fee Vault.

Response

Augustus calldata + tx fields.

Augustus calldata + tx envelope ready to broadcast.

​
from
string

End-user wallet address (the userAddress from the request).

Pattern: ^0x[a-fA-F0-9]{40}$
Example:

"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

​
to
string

The Augustus v6.2 router. Send the transaction here; it is also the ERC-20 spender to approve.

Pattern: ^0x[a-fA-F0-9]{40}$
Example:

"0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"

​
value
string

Native token amount in WEI to send with the transaction. "0" for ERC-20 sources.

Example:

"0"

​
data
string

Encoded swap calldata.

​
gasPrice
string

Suggested gas price in WEI. Replaced by maxFeePerGas / maxPriorityFeePerGas when eip1559=true.

Example:

"16000000000"

​
maxFeePerGas
string

EIP-1559 max fee per gas in WEI. Present when eip1559=true.

​
maxPriorityFeePerGas
string

EIP-1559 max priority fee per gas in WEI. Present when eip1559=true.

​
gas
string

Gas limit estimate from the API's transaction checks. Returned by POST /transactions unless ignoreChecks or ignoreGasEstimate is set; omitted by GET /swap, where you estimate locally before broadcasting.

​
chainId
integer

EVM chain ID. Supported values today include 1 (Mainnet), 10 (Optimism), 56 (BSC), 137 (Polygon), 8453 (Base), 42161 (Arbitrum), 43114 (Avalanche), 100 (Gnosis). The set is open — call GET /chains for the live list.

Example:

1

Last modified on June 14, 2026