curl --request POST \
  --url https://api.grainfinance.co/v1/conversions/accept-quote \
  --header 'Authorization: Basic <encoded-value>' \
  --header 'Content-Type: application/json' \
  --header 'X-Customer-IP: <x-customer-ip>' \
  --data '
{
  "conversionProposalId": "8173b9a7-ee61-413e-b9e3-7c04b2a067c5",
  "toCurrencyAmount": 1560,
  "extraFields": {
    "field_a": "value_a",
    "field_b": "value_b"
  }
}
'

import requests

url = "https://api.grainfinance.co/v1/conversions/accept-quote"

payload = {
    "conversionProposalId": "8173b9a7-ee61-413e-b9e3-7c04b2a067c5",
    "toCurrencyAmount": 1560,
    "extraFields": {
        "field_a": "value_a",
        "field_b": "value_b"
    }
}
headers = {
    "X-Customer-IP": "<x-customer-ip>",
    "Authorization": "Basic <encoded-value>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {
    'X-Customer-IP': '<x-customer-ip>',
    Authorization: 'Basic <encoded-value>',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    conversionProposalId: '8173b9a7-ee61-413e-b9e3-7c04b2a067c5',
    toCurrencyAmount: 1560,
    extraFields: {field_a: 'value_a', field_b: 'value_b'}
  })
};

fetch('https://api.grainfinance.co/v1/conversions/accept-quote', 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.grainfinance.co/v1/conversions/accept-quote",
  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([
    'conversionProposalId' => '8173b9a7-ee61-413e-b9e3-7c04b2a067c5',
    'toCurrencyAmount' => 1560,
    'extraFields' => [
        'field_a' => 'value_a',
        'field_b' => 'value_b'
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Basic <encoded-value>",
    "Content-Type: application/json",
    "X-Customer-IP: <x-customer-ip>"
  ],
]);

$response = curl_exec($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.grainfinance.co/v1/conversions/accept-quote"

	payload := strings.NewReader("{\n  \"conversionProposalId\": \"8173b9a7-ee61-413e-b9e3-7c04b2a067c5\",\n  \"toCurrencyAmount\": 1560,\n  \"extraFields\": {\n    \"field_a\": \"value_a\",\n    \"field_b\": \"value_b\"\n  }\n}")

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

	req.Header.Add("X-Customer-IP", "<x-customer-ip>")
	req.Header.Add("Authorization", "Basic <encoded-value>")
	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.grainfinance.co/v1/conversions/accept-quote")
  .header("X-Customer-IP", "<x-customer-ip>")
  .header("Authorization", "Basic <encoded-value>")
  .header("Content-Type", "application/json")
  .body("{\n  \"conversionProposalId\": \"8173b9a7-ee61-413e-b9e3-7c04b2a067c5\",\n  \"toCurrencyAmount\": 1560,\n  \"extraFields\": {\n    \"field_a\": \"value_a\",\n    \"field_b\": \"value_b\"\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.grainfinance.co/v1/conversions/accept-quote")

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

request = Net::HTTP::Post.new(url)
request["X-Customer-IP"] = '<x-customer-ip>'
request["Authorization"] = 'Basic <encoded-value>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"conversionProposalId\": \"8173b9a7-ee61-413e-b9e3-7c04b2a067c5\",\n  \"toCurrencyAmount\": 1560,\n  \"extraFields\": {\n    \"field_a\": \"value_a\",\n    \"field_b\": \"value_b\"\n  }\n}"

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

{
  "id": "4d78ac65-2c3f-47e2-8bf3-3f76124e9d27"
}

{
  "message": "Can't perform this action",
  "reason": "Supplied object is in *Cancelled* state, which prevents performing this action"
}

{
  "message": "Can't perform this action",
  "reason": "Supplied object is in *Cancelled* state, which prevents performing this action"
}

{
  "message": "Can't perform this action",
  "reason": "Supplied object is in *Cancelled* state, which prevents performing this action"
}

{
  "message": "Can't perform this action",
  "reason": "Supplied object is in *Cancelled* state, which prevents performing this action"
}

{
  "message": "Can't perform this action",
  "reason": "Supplied object is in *Cancelled* state, which prevents performing this action"
}

{
  "message": "Could not parse IP address (v4 or v6) for ip"
}