Simple Swap - LeoKit Documentation

Simple swap

curl --request POST \
  --url https://api.leokit.dev/simple \
  --header 'Api-Key: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "from_asset": "ETH.ETH",
  "to_asset": "ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
  "amount": "0.5",
  "from_address": "0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0",
  "to_address": "0x1234567890AbcdEF1234567890aBcdef12345678",
  "slippage_bps": "100"
}
'

import requests

url = "https://api.leokit.dev/simple"

payload = {
    "from_asset": "ETH.ETH",
    "to_asset": "ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
    "amount": "0.5",
    "from_address": "0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0",
    "to_address": "0x1234567890AbcdEF1234567890aBcdef12345678",
    "slippage_bps": "100"
}
headers = {
    "Api-Key": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {'Api-Key': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    from_asset: 'ETH.ETH',
    to_asset: 'ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831',
    amount: '0.5',
    from_address: '0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0',
    to_address: '0x1234567890AbcdEF1234567890aBcdef12345678',
    slippage_bps: '100'
  })
};

fetch('https://api.leokit.dev/simple', 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.leokit.dev/simple",
  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([
    'from_asset' => 'ETH.ETH',
    'to_asset' => 'ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831',
    'amount' => '0.5',
    'from_address' => '0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0',
    'to_address' => '0x1234567890AbcdEF1234567890aBcdef12345678',
    'slippage_bps' => '100'
  ]),
  CURLOPT_HTTPHEADER => [
    "Api-Key: <api-key>",
    "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.leokit.dev/simple"

	payload := strings.NewReader("{\n  \"from_asset\": \"ETH.ETH\",\n  \"to_asset\": \"ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831\",\n  \"amount\": \"0.5\",\n  \"from_address\": \"0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0\",\n  \"to_address\": \"0x1234567890AbcdEF1234567890aBcdef12345678\",\n  \"slippage_bps\": \"100\"\n}")

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

	req.Header.Add("Api-Key", "<api-key>")
	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.leokit.dev/simple")
  .header("Api-Key", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"from_asset\": \"ETH.ETH\",\n  \"to_asset\": \"ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831\",\n  \"amount\": \"0.5\",\n  \"from_address\": \"0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0\",\n  \"to_address\": \"0x1234567890AbcdEF1234567890aBcdef12345678\",\n  \"slippage_bps\": \"100\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.leokit.dev/simple")

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

request = Net::HTTP::Post.new(url)
request["Api-Key"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"from_asset\": \"ETH.ETH\",\n  \"to_asset\": \"ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831\",\n  \"amount\": \"0.5\",\n  \"from_address\": \"0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0\",\n  \"to_address\": \"0x1234567890AbcdEF1234567890aBcdef12345678\",\n  \"slippage_bps\": \"100\"\n}"

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

{
  "quote_id": "01936b4a-7c8e-7890-abcd-ef1234567890",
  "protocol": "chainflip",
  "deposit_address": "0x8a3c1f2d4e5f67890abcdef1234567890abcdef1",
  "amount": "0.5",
  "amount_raw": "500000000000000000",
  "decimals": 18,
  "from_asset": "ETH.ETH",
  "to_asset": "ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
  "network": "ETH",
  "expected_amount_out": 499.5,
  "expected_amount_out_usd": 499.5,
  "total_swap_seconds": 120,
  "fees": [
    {
      "type": "Network Fee",
      "asset": "ETH",
      "amount": 0.001,
      "usd": 2.5
    }
  ],
  "payment_uri": "ethereum:0x8a3c1f2d4e5f67890abcdef1234567890abcdef1@1?value=500000000000000000",
  "qr_url": "https://cdn.leokit.dev/qr/01936b4a-7c8e-7890-abcd-ef1234567890.png",
  "expires_at": 1707400000
}

{
  "message": "Missing required params: from_asset, to_asset, amount, from_address, to_address",
  "code": "MISSING_PARAMS"
}

{
  "message": "No quotes available for this pair",
  "code": "NO_QUOTES"
}

{
  "message": "<string>",
  "code": "<string>"
}

POST

simple

Simple swap

curl --request POST \
  --url https://api.leokit.dev/simple \
  --header 'Api-Key: <api-key>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "from_asset": "ETH.ETH",
  "to_asset": "ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
  "amount": "0.5",
  "from_address": "0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0",
  "to_address": "0x1234567890AbcdEF1234567890aBcdef12345678",
  "slippage_bps": "100"
}
'

import requests

url = "https://api.leokit.dev/simple"

payload = {
    "from_asset": "ETH.ETH",
    "to_asset": "ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
    "amount": "0.5",
    "from_address": "0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0",
    "to_address": "0x1234567890AbcdEF1234567890aBcdef12345678",
    "slippage_bps": "100"
}
headers = {
    "Api-Key": "<api-key>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {'Api-Key': '<api-key>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    from_asset: 'ETH.ETH',
    to_asset: 'ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831',
    amount: '0.5',
    from_address: '0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0',
    to_address: '0x1234567890AbcdEF1234567890aBcdef12345678',
    slippage_bps: '100'
  })
};

fetch('https://api.leokit.dev/simple', 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.leokit.dev/simple",
  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([
    'from_asset' => 'ETH.ETH',
    'to_asset' => 'ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831',
    'amount' => '0.5',
    'from_address' => '0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0',
    'to_address' => '0x1234567890AbcdEF1234567890aBcdef12345678',
    'slippage_bps' => '100'
  ]),
  CURLOPT_HTTPHEADER => [
    "Api-Key: <api-key>",
    "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.leokit.dev/simple"

	payload := strings.NewReader("{\n  \"from_asset\": \"ETH.ETH\",\n  \"to_asset\": \"ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831\",\n  \"amount\": \"0.5\",\n  \"from_address\": \"0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0\",\n  \"to_address\": \"0x1234567890AbcdEF1234567890aBcdef12345678\",\n  \"slippage_bps\": \"100\"\n}")

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

	req.Header.Add("Api-Key", "<api-key>")
	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.leokit.dev/simple")
  .header("Api-Key", "<api-key>")
  .header("Content-Type", "application/json")
  .body("{\n  \"from_asset\": \"ETH.ETH\",\n  \"to_asset\": \"ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831\",\n  \"amount\": \"0.5\",\n  \"from_address\": \"0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0\",\n  \"to_address\": \"0x1234567890AbcdEF1234567890aBcdef12345678\",\n  \"slippage_bps\": \"100\"\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.leokit.dev/simple")

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

request = Net::HTTP::Post.new(url)
request["Api-Key"] = '<api-key>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"from_asset\": \"ETH.ETH\",\n  \"to_asset\": \"ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831\",\n  \"amount\": \"0.5\",\n  \"from_address\": \"0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0\",\n  \"to_address\": \"0x1234567890AbcdEF1234567890aBcdef12345678\",\n  \"slippage_bps\": \"100\"\n}"

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

{
  "quote_id": "01936b4a-7c8e-7890-abcd-ef1234567890",
  "protocol": "chainflip",
  "deposit_address": "0x8a3c1f2d4e5f67890abcdef1234567890abcdef1",
  "amount": "0.5",
  "amount_raw": "500000000000000000",
  "decimals": 18,
  "from_asset": "ETH.ETH",
  "to_asset": "ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
  "network": "ETH",
  "expected_amount_out": 499.5,
  "expected_amount_out_usd": 499.5,
  "total_swap_seconds": 120,
  "fees": [
    {
      "type": "Network Fee",
      "asset": "ETH",
      "amount": 0.001,
      "usd": 2.5
    }
  ],
  "payment_uri": "ethereum:0x8a3c1f2d4e5f67890abcdef1234567890abcdef1@1?value=500000000000000000",
  "qr_url": "https://cdn.leokit.dev/qr/01936b4a-7c8e-7890-abcd-ef1234567890.png",
  "expires_at": 1707400000
}

{
  "message": "Missing required params: from_asset, to_asset, amount, from_address, to_address",
  "code": "MISSING_PARAMS"
}

{
  "message": "No quotes available for this pair",
  "code": "NO_QUOTES"
}

{
  "message": "<string>",
  "code": "<string>"
}

How It Works

POST /leokit/simple     → Quotes Chainflip & NEAR, picks best, returns deposit + QR
User scans QR or sends  → Sends funds to the deposit address
POST /leokit/status     → Poll with quote_id for swap completion

Compared to the standard multi-step flow (/quote → /deposit), this reduces two API calls to one. Only works with deposit-address-based protocols (Chainflip and NEAR).

Payment URI Standards

The payment_uri follows the wallet standard for the source chain:

Source Chain	Standard	Example
BTC, LTC, DOGE, DASH	BIP-21	`bitcoin:bc1q...?amount=0.5`
ETH, ARB, BASE (native)	EIP-681	`ethereum:0x...@1?value=500000000000000000`
ETH, ARB, BASE (ERC20)	EIP-681	`ethereum:0xTOKEN@1/transfer?address=0x...&uint256=`
SOL (native)	Solana Pay	`solana:So1...?amount=2`
Other	Fallback	Plain deposit address

Example: BTC to ETH

curl -X POST https://api.leokit.dev/leokit/simple \
  -H "Content-Type: application/json" \
  -H "Api-Key: YOUR_API_KEY" \
  -d '{
    "from_asset": "BTC.BTC",
    "to_asset": "ETH.ETH",
    "amount": "0.01",
    "from_address": "bc1q...",
    "to_address": "0x1234567890AbcdEF1234567890aBcdef12345678"
  }'

Errors

Status	Code	Description
`400`	`INVALID_ASSET`	`from_asset` or `to_asset` is malformed or not in the supported list
`400`	`INVALID_ADDRESS`	`from_address` or `to_address` not valid for the source/destination chain
`400`	`UNSUPPORTED_PAIR`	No deposit-address-based route (Chainflip/NEAR) available for the pair
`401`	`INVALID_API_KEY`	Missing or invalid `Api-Key` header
`404`	`NO_QUOTE_AVAILABLE`	All deposit-address protocols rejected the pair
`500`	`INTERNAL_ERROR`	Quote or deposit generation failed unexpectedly

See the error codes catalog for the full list.

Authorizations

Api-Key

string

header

required

Demo API-Key (Sandbox): 7037d2b3-9c76-4f62-b730-c544f7570fa4

Body

application/json

Request body for /simple. One-call swap endpoint for deposit-address protocols.

from_asset

string

required

Source asset identifier (CHAIN.SYMBOL-ADDRESS).

Example:

"ETH.ETH"

to_asset

string

required

Destination asset identifier (CHAIN.SYMBOL-ADDRESS).

Example:

"ARB.USDC-0xaf88d065e77c8cC2239327C5EDb3A432268e5831"

amount

string

required

Human-readable amount to swap.

Example:

"0.5"

from_address

string

required

Sender address on the source chain (used as refund address).

Example:

"0x742d35Cc6634C0532925a3b844Bc9e7595f0bEb0"

to_address

string

required

Recipient address on the destination chain.

Example:

"0x1234567890AbcdEF1234567890aBcdef12345678"

slippage_bps

string

Slippage tolerance in basis points. Defaults to 150 (1.5%).

Example:

"100"

Response

Simple swap response with quote, deposit address, and QR code.

Response from /simple containing quote, deposit address, and QR code.

quote_id

string<uuid>

required

Quote identifier for tracking via /status.

protocol

enum<string>

required

Protocol selected (always chainflip or near).

Available options:

chainflip,

near

deposit_address

string

required

Address to send funds to.

amount

string

required

Human-readable amount to send.

amount_raw

string

required

Amount in smallest unit (wei, sats, etc.).

decimals

integer

required

Decimal places for the source asset.

from_asset

string

required

Source asset identifier.

to_asset

string

required

Destination asset identifier.

network

string

required

Source chain short name (e.g. ETH, BTC).

expected_amount_out

number

required

Expected output amount (human-readable).

payment_uri

string

required

Chain-specific payment URI (BIP-21, EIP-681, or Solana Pay).

qr_url

string

required

CDN URL of a QR code PNG encoding the payment_uri.

expected_amount_out_usd

number | null

Expected output in USD.

total_swap_seconds

integer | null

Estimated swap time in seconds.

fees

object[]

Fee breakdown.

Show child attributes

expires_at

integer<int64> | null

Unix timestamp (seconds) when the deposit channel expires.

Deposit Address Notify Deposit

​How It Works

​Payment URI Standards

​Example: BTC to ETH

​Errors

Authorizations

Body

Response

How It Works

Payment URI Standards

Example: BTC to ETH

Errors