curl --request POST \
  --url https://api-sandbox.circle.com/v1/accounts/transfers \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "idempotencyKey": "ba943ff1-ca16-49b2-ba55-1057e70ca5c7",
  "source": {
    "type": "account",
    "id": "1000565227"
  },
  "destination": {
    "type": "account",
    "id": "1000662322"
  },
  "amount": {
    "amount": "10.00",
    "currency": "USD"
  }
}
'

import requests

url = "https://api-sandbox.circle.com/v1/accounts/transfers"

payload = {
    "idempotencyKey": "ba943ff1-ca16-49b2-ba55-1057e70ca5c7",
    "source": {
        "type": "account",
        "id": "1000565227"
    },
    "destination": {
        "type": "account",
        "id": "1000662322"
    },
    "amount": {
        "amount": "10.00",
        "currency": "USD"
    }
}
headers = {
    "Authorization": "Bearer <token>",
    "Content-Type": "application/json"
}

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

print(response.text)

const options = {
  method: 'POST',
  headers: {Authorization: 'Bearer <token>', 'Content-Type': 'application/json'},
  body: JSON.stringify({
    idempotencyKey: 'ba943ff1-ca16-49b2-ba55-1057e70ca5c7',
    source: {type: 'account', id: '1000565227'},
    destination: {type: 'account', id: '1000662322'},
    amount: {amount: '10.00', currency: 'USD'}
  })
};

fetch('https://api-sandbox.circle.com/v1/accounts/transfers', 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-sandbox.circle.com/v1/accounts/transfers",
  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([
    'idempotencyKey' => 'ba943ff1-ca16-49b2-ba55-1057e70ca5c7',
    'source' => [
        'type' => 'account',
        'id' => '1000565227'
    ],
    'destination' => [
        'type' => 'account',
        'id' => '1000662322'
    ],
    'amount' => [
        'amount' => '10.00',
        'currency' => 'USD'
    ]
  ]),
  CURLOPT_HTTPHEADER => [
    "Authorization: Bearer <token>",
    "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-sandbox.circle.com/v1/accounts/transfers"

	payload := strings.NewReader("{\n  \"idempotencyKey\": \"ba943ff1-ca16-49b2-ba55-1057e70ca5c7\",\n  \"source\": {\n    \"type\": \"account\",\n    \"id\": \"1000565227\"\n  },\n  \"destination\": {\n    \"type\": \"account\",\n    \"id\": \"1000662322\"\n  },\n  \"amount\": {\n    \"amount\": \"10.00\",\n    \"currency\": \"USD\"\n  }\n}")

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

	req.Header.Add("Authorization", "Bearer <token>")
	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-sandbox.circle.com/v1/accounts/transfers")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"idempotencyKey\": \"ba943ff1-ca16-49b2-ba55-1057e70ca5c7\",\n  \"source\": {\n    \"type\": \"account\",\n    \"id\": \"1000565227\"\n  },\n  \"destination\": {\n    \"type\": \"account\",\n    \"id\": \"1000662322\"\n  },\n  \"amount\": {\n    \"amount\": \"10.00\",\n    \"currency\": \"USD\"\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api-sandbox.circle.com/v1/accounts/transfers")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = 'Bearer <token>'
request["Content-Type"] = 'application/json'
request.body = "{\n  \"idempotencyKey\": \"ba943ff1-ca16-49b2-ba55-1057e70ca5c7\",\n  \"source\": {\n    \"type\": \"account\",\n    \"id\": \"1000565227\"\n  },\n  \"destination\": {\n    \"type\": \"account\",\n    \"id\": \"1000662322\"\n  },\n  \"amount\": {\n    \"amount\": \"10.00\",\n    \"currency\": \"USD\"\n  }\n}"

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

{
  "data": {
    "id": "b8627ae8-732b-4d25-b947-1df8f4007a29",
    "source": {
      "type": "account",
      "id": "1000565227",
      "description": "Your Payments Account"
    },
    "destination": {
      "type": "account",
      "id": "1000662322",
      "description": "Merchant Subledger Account"
    },
    "amount": {
      "amount": "10.00",
      "currency": "USD"
    },
    "status": "pending",
    "createDate": "2020-04-10T02:13:30.000Z"
  }
}

{
  "code": 400,
  "message": "Bad request."
}

{
  "code": 401,
  "message": "Malformed authorization."
}

{
  "code": 3,
  "message": "Forbidden"
}

{
  "code": 500,
  "message": "Internal server error."
}