Build Swap

Build swap transaction

curl --request POST \
  --url https://api.vulcx.xyz/api/v1/swap \
  --header 'Content-Type: application/json' \
  --data '
{
  "userWallet": "9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM",
  "inputMint": "So11111111111111111111111111111111111111112",
  "outputMint": "uSd2czE61Evaf76RNbq4KPpXnkiL3irdzgLFUMe3NoG",
  "amount": "1000000000",
  "swapMode": "ExactIn",
  "slippageBps": 50,
  "skipSimulation": false,
  "quoteId": "q_b15372a8d82a93d1e328ae24e5d3669a",
  "firm": false,
  "referrer": "EJxE7RDaP5pmoVzzHRb4fufCNq3wsCgdUbJ8PCXHZNUP",
  "integratorFeeBps": 20
}
'

import requests

url = "https://api.vulcx.xyz/api/v1/swap"

payload = {
    "userWallet": "9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM",
    "inputMint": "So11111111111111111111111111111111111111112",
    "outputMint": "uSd2czE61Evaf76RNbq4KPpXnkiL3irdzgLFUMe3NoG",
    "amount": "1000000000",
    "swapMode": "ExactIn",
    "slippageBps": 50,
    "skipSimulation": False,
    "quoteId": "q_b15372a8d82a93d1e328ae24e5d3669a",
    "firm": False,
    "referrer": "EJxE7RDaP5pmoVzzHRb4fufCNq3wsCgdUbJ8PCXHZNUP",
    "integratorFeeBps": 20
}
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({
    userWallet: '9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM',
    inputMint: 'So11111111111111111111111111111111111111112',
    outputMint: 'uSd2czE61Evaf76RNbq4KPpXnkiL3irdzgLFUMe3NoG',
    amount: '1000000000',
    swapMode: 'ExactIn',
    slippageBps: 50,
    skipSimulation: false,
    quoteId: 'q_b15372a8d82a93d1e328ae24e5d3669a',
    firm: false,
    referrer: 'EJxE7RDaP5pmoVzzHRb4fufCNq3wsCgdUbJ8PCXHZNUP',
    integratorFeeBps: 20
  })
};

fetch('https://api.vulcx.xyz/api/v1/swap', 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.vulcx.xyz/api/v1/swap",
  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([
    'userWallet' => '9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM',
    'inputMint' => 'So11111111111111111111111111111111111111112',
    'outputMint' => 'uSd2czE61Evaf76RNbq4KPpXnkiL3irdzgLFUMe3NoG',
    'amount' => '1000000000',
    'swapMode' => 'ExactIn',
    'slippageBps' => 50,
    'skipSimulation' => false,
    'quoteId' => 'q_b15372a8d82a93d1e328ae24e5d3669a',
    'firm' => false,
    'referrer' => 'EJxE7RDaP5pmoVzzHRb4fufCNq3wsCgdUbJ8PCXHZNUP',
    'integratorFeeBps' => 20
  ]),
  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.vulcx.xyz/api/v1/swap"

	payload := strings.NewReader("{\n  \"userWallet\": \"9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM\",\n  \"inputMint\": \"So11111111111111111111111111111111111111112\",\n  \"outputMint\": \"uSd2czE61Evaf76RNbq4KPpXnkiL3irdzgLFUMe3NoG\",\n  \"amount\": \"1000000000\",\n  \"swapMode\": \"ExactIn\",\n  \"slippageBps\": 50,\n  \"skipSimulation\": false,\n  \"quoteId\": \"q_b15372a8d82a93d1e328ae24e5d3669a\",\n  \"firm\": false,\n  \"referrer\": \"EJxE7RDaP5pmoVzzHRb4fufCNq3wsCgdUbJ8PCXHZNUP\",\n  \"integratorFeeBps\": 20\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.vulcx.xyz/api/v1/swap")
  .header("Content-Type", "application/json")
  .body("{\n  \"userWallet\": \"9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM\",\n  \"inputMint\": \"So11111111111111111111111111111111111111112\",\n  \"outputMint\": \"uSd2czE61Evaf76RNbq4KPpXnkiL3irdzgLFUMe3NoG\",\n  \"amount\": \"1000000000\",\n  \"swapMode\": \"ExactIn\",\n  \"slippageBps\": 50,\n  \"skipSimulation\": false,\n  \"quoteId\": \"q_b15372a8d82a93d1e328ae24e5d3669a\",\n  \"firm\": false,\n  \"referrer\": \"EJxE7RDaP5pmoVzzHRb4fufCNq3wsCgdUbJ8PCXHZNUP\",\n  \"integratorFeeBps\": 20\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.vulcx.xyz/api/v1/swap")

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  \"userWallet\": \"9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM\",\n  \"inputMint\": \"So11111111111111111111111111111111111111112\",\n  \"outputMint\": \"uSd2czE61Evaf76RNbq4KPpXnkiL3irdzgLFUMe3NoG\",\n  \"amount\": \"1000000000\",\n  \"swapMode\": \"ExactIn\",\n  \"slippageBps\": 50,\n  \"skipSimulation\": false,\n  \"quoteId\": \"q_b15372a8d82a93d1e328ae24e5d3669a\",\n  \"firm\": false,\n  \"referrer\": \"EJxE7RDaP5pmoVzzHRb4fufCNq3wsCgdUbJ8PCXHZNUP\",\n  \"integratorFeeBps\": 20\n}"

response = http.request(request)
puts response.read_body

{
  "success": true,
  "data": {
    "transaction": "<string>",
    "lastValidBlockHeight": 245832190,
    "amountIn": "1000000000",
    "amountOut": "145320000",
    "feeAmount": "0",
    "computeUnitsEstimate": 85000,
    "route": [
      "<string>"
    ],
    "hopCount": 1,
    "pools": [
      "<string>"
    ],
    "isSplitRoute": false,
    "minAmountOut": "<string>",
    "maxAmountIn": "<string>",
    "simulation": {
      "success": true,
      "logs": [
        "<string>"
      ],
      "computeUnitsConsumed": 85000,
      "insufficientFunds": true,
      "slippageExceeded": true,
      "error": "<string>"
    },
    "splitPercents": [
      123
    ],
    "platformFeeBps": 20,
    "platformFeeAmount": "29064",
    "integratorFeeBps": 20,
    "integratorFeeAmount": "29064"
  }
}

{
  "success": false,
  "error": "no route found"
}

{
  "success": false,
  "error": "invalid api key"
}

{
  "success": false,
  "error": "no route found"
}

{
  "success": false,
  "error": "no route found"
}

{
  "success": false,
  "error": "no route found"
}

{
  "success": false,
  "error": "no route found"
}

{
  "success": false,
  "error": "rate limit exceeded"
}

{
  "success": false,
  "error": "no route found"
}

POST

api

swap

Build swap transaction

curl --request POST \
  --url https://api.vulcx.xyz/api/v1/swap \
  --header 'Content-Type: application/json' \
  --data '
{
  "userWallet": "9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM",
  "inputMint": "So11111111111111111111111111111111111111112",
  "outputMint": "uSd2czE61Evaf76RNbq4KPpXnkiL3irdzgLFUMe3NoG",
  "amount": "1000000000",
  "swapMode": "ExactIn",
  "slippageBps": 50,
  "skipSimulation": false,
  "quoteId": "q_b15372a8d82a93d1e328ae24e5d3669a",
  "firm": false,
  "referrer": "EJxE7RDaP5pmoVzzHRb4fufCNq3wsCgdUbJ8PCXHZNUP",
  "integratorFeeBps": 20
}
'

import requests

url = "https://api.vulcx.xyz/api/v1/swap"

payload = {
    "userWallet": "9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM",
    "inputMint": "So11111111111111111111111111111111111111112",
    "outputMint": "uSd2czE61Evaf76RNbq4KPpXnkiL3irdzgLFUMe3NoG",
    "amount": "1000000000",
    "swapMode": "ExactIn",
    "slippageBps": 50,
    "skipSimulation": False,
    "quoteId": "q_b15372a8d82a93d1e328ae24e5d3669a",
    "firm": False,
    "referrer": "EJxE7RDaP5pmoVzzHRb4fufCNq3wsCgdUbJ8PCXHZNUP",
    "integratorFeeBps": 20
}
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({
    userWallet: '9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM',
    inputMint: 'So11111111111111111111111111111111111111112',
    outputMint: 'uSd2czE61Evaf76RNbq4KPpXnkiL3irdzgLFUMe3NoG',
    amount: '1000000000',
    swapMode: 'ExactIn',
    slippageBps: 50,
    skipSimulation: false,
    quoteId: 'q_b15372a8d82a93d1e328ae24e5d3669a',
    firm: false,
    referrer: 'EJxE7RDaP5pmoVzzHRb4fufCNq3wsCgdUbJ8PCXHZNUP',
    integratorFeeBps: 20
  })
};

fetch('https://api.vulcx.xyz/api/v1/swap', 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.vulcx.xyz/api/v1/swap",
  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([
    'userWallet' => '9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM',
    'inputMint' => 'So11111111111111111111111111111111111111112',
    'outputMint' => 'uSd2czE61Evaf76RNbq4KPpXnkiL3irdzgLFUMe3NoG',
    'amount' => '1000000000',
    'swapMode' => 'ExactIn',
    'slippageBps' => 50,
    'skipSimulation' => false,
    'quoteId' => 'q_b15372a8d82a93d1e328ae24e5d3669a',
    'firm' => false,
    'referrer' => 'EJxE7RDaP5pmoVzzHRb4fufCNq3wsCgdUbJ8PCXHZNUP',
    'integratorFeeBps' => 20
  ]),
  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.vulcx.xyz/api/v1/swap"

	payload := strings.NewReader("{\n  \"userWallet\": \"9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM\",\n  \"inputMint\": \"So11111111111111111111111111111111111111112\",\n  \"outputMint\": \"uSd2czE61Evaf76RNbq4KPpXnkiL3irdzgLFUMe3NoG\",\n  \"amount\": \"1000000000\",\n  \"swapMode\": \"ExactIn\",\n  \"slippageBps\": 50,\n  \"skipSimulation\": false,\n  \"quoteId\": \"q_b15372a8d82a93d1e328ae24e5d3669a\",\n  \"firm\": false,\n  \"referrer\": \"EJxE7RDaP5pmoVzzHRb4fufCNq3wsCgdUbJ8PCXHZNUP\",\n  \"integratorFeeBps\": 20\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.vulcx.xyz/api/v1/swap")
  .header("Content-Type", "application/json")
  .body("{\n  \"userWallet\": \"9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM\",\n  \"inputMint\": \"So11111111111111111111111111111111111111112\",\n  \"outputMint\": \"uSd2czE61Evaf76RNbq4KPpXnkiL3irdzgLFUMe3NoG\",\n  \"amount\": \"1000000000\",\n  \"swapMode\": \"ExactIn\",\n  \"slippageBps\": 50,\n  \"skipSimulation\": false,\n  \"quoteId\": \"q_b15372a8d82a93d1e328ae24e5d3669a\",\n  \"firm\": false,\n  \"referrer\": \"EJxE7RDaP5pmoVzzHRb4fufCNq3wsCgdUbJ8PCXHZNUP\",\n  \"integratorFeeBps\": 20\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.vulcx.xyz/api/v1/swap")

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  \"userWallet\": \"9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM\",\n  \"inputMint\": \"So11111111111111111111111111111111111111112\",\n  \"outputMint\": \"uSd2czE61Evaf76RNbq4KPpXnkiL3irdzgLFUMe3NoG\",\n  \"amount\": \"1000000000\",\n  \"swapMode\": \"ExactIn\",\n  \"slippageBps\": 50,\n  \"skipSimulation\": false,\n  \"quoteId\": \"q_b15372a8d82a93d1e328ae24e5d3669a\",\n  \"firm\": false,\n  \"referrer\": \"EJxE7RDaP5pmoVzzHRb4fufCNq3wsCgdUbJ8PCXHZNUP\",\n  \"integratorFeeBps\": 20\n}"

response = http.request(request)
puts response.read_body

{
  "success": true,
  "data": {
    "transaction": "<string>",
    "lastValidBlockHeight": 245832190,
    "amountIn": "1000000000",
    "amountOut": "145320000",
    "feeAmount": "0",
    "computeUnitsEstimate": 85000,
    "route": [
      "<string>"
    ],
    "hopCount": 1,
    "pools": [
      "<string>"
    ],
    "isSplitRoute": false,
    "minAmountOut": "<string>",
    "maxAmountIn": "<string>",
    "simulation": {
      "success": true,
      "logs": [
        "<string>"
      ],
      "computeUnitsConsumed": 85000,
      "insufficientFunds": true,
      "slippageExceeded": true,
      "error": "<string>"
    },
    "splitPercents": [
      123
    ],
    "platformFeeBps": 20,
    "platformFeeAmount": "29064",
    "integratorFeeBps": 20,
    "integratorFeeAmount": "29064"
  }
}

{
  "success": false,
  "error": "no route found"
}

{
  "success": false,
  "error": "invalid api key"
}

{
  "success": false,
  "error": "no route found"
}

{
  "success": false,
  "error": "no route found"
}

{
  "success": false,
  "error": "no route found"
}

{
  "success": false,
  "error": "no route found"
}

{
  "success": false,
  "error": "rate limit exceeded"
}

{
  "success": false,
  "error": "no route found"
}

Headers

Authorization

string

Optional API key: Bearer vulcx_.... Anonymous calls are allowed but capped at a small per-IP rate limit — see Rate limits.

Example:

"Bearer vulcx_..."

Body

application/json

Parameters for building a swap transaction.

userWallet

string

required

User's wallet address that will sign and execute the transaction.

Example:

"9WzDXwBbmkg8ZTbNMqUxvQRAyrZzDsGYdLVL9zYtAWWM"

inputMint

string

required

Input token mint address.

Example:

"So11111111111111111111111111111111111111112"

outputMint

string

required

Output token mint address.

Example:

"uSd2czE61Evaf76RNbq4KPpXnkiL3irdzgLFUMe3NoG"

amount

string

required

Amount in smallest token units.

Example:

"1000000000"

swapMode

enum<string>

required

ExactIn: amount is exact input. ExactOut: amount is exact desired output.

Available options:

ExactIn,

ExactOut

Example:

"ExactIn"

slippageBps

integer

default:50

Slippage tolerance in basis points. Default: 50 (0.5%).

Example:

50

skipSimulation

boolean

default:false

Skip transaction simulation. Faster but no pre-flight validation. Default: false.

Example:

false

quoteId

string

Optional firm-quote ID from GET /quote (or a WebSocket quote push). Pair, amount, and swapMode must match the original quote. The exact quoted route is replayed and min-out anchors to the quoted price instead of a fresh re-quote.

Example:

"q_b15372a8d82a93d1e328ae24e5d3669a"

firm

boolean

Firm (price-or-fail) redemption — requires quoteId and only works within the quote's firmForMs window. Slippage collapses to the server's firm margin (default 10 bps) around the quoted price; slippageBps is ignored. If the route drifted past the margin the request fails with 409 instead of executing at a worse price.

Example:

false

referrer

string

Optional referrer wallet (base58). Receives integratorFeeBps in full, paid on-chain in the output token in the same transaction as the swap. Required whenever integratorFeeBps is set.

Example:

"EJxE7RDaP5pmoVzzHRb4fufCNq3wsCgdUbJ8PCXHZNUP"

integratorFeeBps

integer

Your own fee rate in basis points of the output, kept by you in full. Requires referrer — a rate with no wallet to pay it to returns 400. Added to platformFeeBps, not carved out of it; the sum may not exceed 100 bps.

Required range: 0 <= x <= 100

Example:

20

Response

Swap transaction built successfully.

success

boolean

Example:

true

data

object

Unsigned swap transaction and execution details.

Show child attributes

Last modified on August 31, 2026

Overview

Endpoints

Headers

Body

Response