FORM API (x-www-form-urlencoded API)


This type of API is based on the form x-www-form-urlencoded type of web-requests (POST) as described here: POST HTTP - MDN Web Docs

The Content-Type on the request headers is set to application/x-www-form-urlencoded


If you like to send multiple SMS with one request you are advised to use the JSON API (application/json API), which offers more flexibility.