Examples

All of these examples should be immediately runnable in your language of choice. If you don't see your language feel free to contribute an example.

Curl

# Optimising a JPG file (e.g. filename.jpg -> optimised.jpg)
curl -X POST -s --form "input=@filename.jpg;type=image/jpg" https://www.toptal.com/developers/jpgoptimiser/optimise > optimised.jpg

Node.js

// core
var fs = require('fs');

// from npm
var superagent = require('superagent');

// open the output file
var outStream = fs.createWriteStream('optimised.jpg');

// do the request
var req = superagent
    .post('https://www.toptal.com/developers/jpgoptimiser/optimise')
    .attach('input', 'filename.jpg')
;

// save the returned file
req.end(function(res) {
    res.pipe(outStream);
});

PHP

Many thanks to Arjan Haverkamp for this example and Kevin Op den Kamp for an update.

function JPGoptimiser($JPGfile, &$error = '')
{
   $ch = curl_init('https://www.toptal.com/developers/jpgoptimiser/optimise');
   curl_setopt($ch, CURLOPT_TIMEOUT, 10);
   curl_setopt($ch, CURLOPT_FAILONERROR, 1);
   curl_setopt($ch, CURLOPT_POST, 1);
   curl_setopt($ch, CURLOPT_POSTFIELDS, [
      'input' => new CurlFile($JPGfile, 'image/jpg', $JPGfile)
   ]);
   curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

   $jpg = curl_exec($ch);
   $status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
   if ($status !== 200) {
      $error = "www.toptal.com request failed: HTTP code {$status}";
      return false;
   }
   $curl_error = curl_error($ch);
   if (!empty($curl_error)) {
      $error = "www.toptal.com request failed: CURL error ${$curl_error}";
      return false;
   }
   curl_close($ch);
   return $jpg;
}

$result = Jpgoptimiser('input.jpg', $error);
if (false === $result) { die("{$error}\n"); }
file_put_contents('optimised.jpg', $result);

(Ends)