curl --request POST \
  --url https://api.withallo.com/v2/api/faxes \
  --header 'Authorization: <api-key>' \
  --header 'Content-Type: multipart/form-data' \
  --form 'from=+14155550100' \
  --form 'to=+14155551234' \
  --form 'file=@example-file;type=application/pdf'

import requests

url = "https://api.withallo.com/v2/api/faxes"

files = { "file": ("example-file", open("example-file", "rb"), "application/pdf") }
payload = {
    "from": "+14155550100",
    "to": "+14155551234"
}
headers = {"Authorization": "<api-key>"}

response = requests.post(url, data=payload, files=files, headers=headers)

print(response.text)

const form = new FormData();
form.append('from', '+14155550100');
form.append('to', '+14155551234');
form.append('file', '<string>');

const options = {method: 'POST', headers: {Authorization: '<api-key>'}};

options.body = form;

fetch('https://api.withallo.com/v2/api/faxes', 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.withallo.com/v2/api/faxes",
  CURLOPT_RETURNTRANSFER => true,
  CURLOPT_ENCODING => "",
  CURLOPT_MAXREDIRS => 10,
  CURLOPT_TIMEOUT => 30,
  CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1,
  CURLOPT_CUSTOMREQUEST => "POST",
  CURLOPT_POSTFIELDS => "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"from\"\r\n\r\n+14155550100\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"to\"\r\n\r\n+14155551234\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example-file\"\r\nContent-Type: application/pdf\r\n\r\n<string>\r\n-----011000010111000001101001--",
  CURLOPT_HTTPHEADER => [
    "Authorization: <api-key>",
    "Content-Type: multipart/form-data"
  ],
]);

$response = curl_exec($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.withallo.com/v2/api/faxes"

	payload := strings.NewReader("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"from\"\r\n\r\n+14155550100\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"to\"\r\n\r\n+14155551234\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example-file\"\r\nContent-Type: application/pdf\r\n\r\n<string>\r\n-----011000010111000001101001--")

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

	req.Header.Add("Authorization", "<api-key>")

	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.withallo.com/v2/api/faxes")
  .header("Authorization", "<api-key>")
  .body("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"from\"\r\n\r\n+14155550100\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"to\"\r\n\r\n+14155551234\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example-file\"\r\nContent-Type: application/pdf\r\n\r\n<string>\r\n-----011000010111000001101001--")
  .asString();

require 'uri'
require 'net/http'

url = URI("https://api.withallo.com/v2/api/faxes")

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

request = Net::HTTP::Post.new(url)
request["Authorization"] = '<api-key>'
request.body = "-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"from\"\r\n\r\n+14155550100\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"to\"\r\n\r\n+14155551234\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example-file\"\r\nContent-Type: application/pdf\r\n\r\n<string>\r\n-----011000010111000001101001--"

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

{
  "data": {
    "id": "msg-abc123",
    "type": "SMS",
    "direction": "OUTBOUND",
    "allo_number": "+14155550100",
    "contact_number": "+14155551234",
    "contacts": [],
    "user": {
      "id": "usr-abc123",
      "name": "Alex Kim",
      "email": "[email protected]"
    },
    "date": "2026-11-10T14:30:00",
    "content": "",
    "status": "PENDING",
    "message_type": "FAX",
    "attachments": [
      {
        "file_name": "contract.pdf",
        "content_type": "application/pdf",
        "file_size": 184320,
        "download_url": "https://...contract.pdf?X-Amz-Expires=1800&X-Amz-Signature=...",
        "download_expires_at": "2026-11-10T15:00:00Z"
      }
    ],
    "page_count": null
  }
}

{
  "error": {
    "type": "<string>",
    "code": "<string>",
    "message": "<string>",
    "retryable": true,
    "request_id": "<string>",
    "retry_after_seconds": 123
  }
}

{
  "error": {
    "type": "<string>",
    "code": "<string>",
    "message": "<string>",
    "retryable": true,
    "request_id": "<string>",
    "retry_after_seconds": 123
  }
}

{
  "error": {
    "type": "<string>",
    "code": "<string>",
    "message": "<string>",
    "retryable": true,
    "request_id": "<string>",
    "retry_after_seconds": 123
  }
}

{
  "error": {
    "type": "<string>",
    "code": "<string>",
    "message": "<string>",
    "retryable": true,
    "request_id": "<string>",
    "retry_after_seconds": 123
  }
}

{
  "error": {
    "type": "<string>",
    "code": "<string>",
    "message": "<string>",
    "retryable": true,
    "request_id": "<string>",
    "retry_after_seconds": 123
  }
}

{
  "error": {
    "type": "<string>",
    "code": "<string>",
    "message": "<string>",
    "retryable": true,
    "request_id": "<string>",
    "retry_after_seconds": 123
  }
}