MMS Attachments are required to be base64 encoded.
Below are some examples of how to encode an attachment in different programming languages.
PHP
$path = 'myfolder/myimage.png';
$type = pathinfo($path, PATHINFO_EXTENSION);
$data = file_get_contents($path);
$base64 = 'data:image/' . $type . ';base64,' . base64_encode($data);
Java
private static String encodeFileToBase64Binary(String fileName) throws IOException {
File file = new File(fileName);
byte[] encoded = Base64.encodeBase64(FileUtils.readFileToByteArray(file));
return new String(encoded, StandardCharsets.US_ASCII);
}
Our full MMS API documentation is available here: MMS API