curl --request POST \
  --url https://integration.smartpng.com/api/compress \
  --header 'Content-Type: multipart/form-data' \
  --form api_key=sp_live_abc123def456ghi789 \
  --form file='@example-file'

import requests

url = "https://integration.smartpng.com/api/compress"

files = { "file": ("example-file", open("example-file", "rb")) }
payload = { "api_key": "sp_live_abc123def456ghi789" }

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

print(response.text)

const form = new FormData();
form.append('api_key', 'sp_live_abc123def456ghi789');
form.append('file', '<string>');

const options = {method: 'POST'};

options.body = form;

fetch('https://integration.smartpng.com/api/compress', 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://integration.smartpng.com/api/compress",
  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=\"api_key\"\r\n\r\nsp_live_abc123def456ghi789\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001--",
  CURLOPT_HTTPHEADER => [
    "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;
}

HttpResponse<String> response = Unirest.post("https://integration.smartpng.com/api/compress")
  .body("-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"api_key\"\r\n\r\nsp_live_abc123def456ghi789\r\n-----011000010111000001101001\r\nContent-Disposition: form-data; name=\"file\"; filename=\"example-file\"\r\nContent-Type: application/octet-stream\r\n\r\n<string>\r\n-----011000010111000001101001--")
  .asString();

using RestSharp;


var options = new RestClientOptions("https://integration.smartpng.com/api/compress");
var client = new RestClient(options);
var request = new RestRequest("");
request.AlwaysMultipartFormData = true;
request.FormBoundary = "---011000010111000001101001";
request.AddParameter("api_key", "sp_live_abc123def456ghi789");
request.AddFile("file", "example-file");
var response = await client.PostAsync(request);

Console.WriteLine("{0}", response.Content);