curl --request POST \
  --url https://api-sandbox.circle.com/v1/externalEntities \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "businessName": "Circle Internet Financial Inc.",
  "businessUniqueIdentifier": "1234567890",
  "identifierIssuingCountryCode": "US",
  "address": {
    "country": "US",
    "state": "MA",
    "city": "Boston",
    "postcode": "01234",
    "streetName": "Main Street",
    "buildingNumber": "100"
  }
}
'

import requests

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

payload = {
    "businessName": "Circle Internet Financial Inc.",
    "businessUniqueIdentifier": "1234567890",
    "identifierIssuingCountryCode": "US",
    "address": {
        "country": "US",
        "state": "MA",
        "city": "Boston",
        "postcode": "01234",
        "streetName": "Main Street",
        "buildingNumber": "100"
    }
}
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({
    businessName: 'Circle Internet Financial Inc.',
    businessUniqueIdentifier: '1234567890',
    identifierIssuingCountryCode: 'US',
    address: {
      country: 'US',
      state: 'MA',
      city: 'Boston',
      postcode: '01234',
      streetName: 'Main Street',
      buildingNumber: '100'
    }
  })
};

fetch('https://api-sandbox.circle.com/v1/externalEntities', 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/externalEntities",
  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([
    'businessName' => 'Circle Internet Financial Inc.',
    'businessUniqueIdentifier' => '1234567890',
    'identifierIssuingCountryCode' => 'US',
    'address' => [
        'country' => 'US',
        'state' => 'MA',
        'city' => 'Boston',
        'postcode' => '01234',
        'streetName' => 'Main Street',
        'buildingNumber' => '100'
    ]
  ]),
  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/externalEntities"

	payload := strings.NewReader("{\n  \"businessName\": \"Circle Internet Financial Inc.\",\n  \"businessUniqueIdentifier\": \"1234567890\",\n  \"identifierIssuingCountryCode\": \"US\",\n  \"address\": {\n    \"country\": \"US\",\n    \"state\": \"MA\",\n    \"city\": \"Boston\",\n    \"postcode\": \"01234\",\n    \"streetName\": \"Main Street\",\n    \"buildingNumber\": \"100\"\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/externalEntities")
  .header("Authorization", "Bearer <token>")
  .header("Content-Type", "application/json")
  .body("{\n  \"businessName\": \"Circle Internet Financial Inc.\",\n  \"businessUniqueIdentifier\": \"1234567890\",\n  \"identifierIssuingCountryCode\": \"US\",\n  \"address\": {\n    \"country\": \"US\",\n    \"state\": \"MA\",\n    \"city\": \"Boston\",\n    \"postcode\": \"01234\",\n    \"streetName\": \"Main Street\",\n    \"buildingNumber\": \"100\"\n  }\n}")
  .asString();

require 'uri'
require 'net/http'

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

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  \"businessName\": \"Circle Internet Financial Inc.\",\n  \"businessUniqueIdentifier\": \"1234567890\",\n  \"identifierIssuingCountryCode\": \"US\",\n  \"address\": {\n    \"country\": \"US\",\n    \"state\": \"MA\",\n    \"city\": \"Boston\",\n    \"postcode\": \"01234\",\n    \"streetName\": \"Main Street\",\n    \"buildingNumber\": \"100\"\n  }\n}"

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

{
  "walletId": "212000",
  "businessName": "Circle Internet Financial Inc.",
  "businessUniqueIdentifier": "1234567890",
  "identifierIssuingCountryCode": "US",
  "complianceState": "PENDING"
}

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

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

{
  "code": 409,
  "message": "Conflicts with another request."
}