Requires a text module for OpenCart / 1C-Bitrix / woocommerce

Good afternoon
For the text message service www.startsend.ru need to develop a module to send text messages via OpenCart / 1C-Bitrix
API is available to describe here: https://app.startsend.ru/api/docs
Priority in consideration is given to the topics:

- the experience of writing modules to send a text message (ideal)
- experience in developing your own modules for the right CMS

If there is some open-source that can be taken and refined - this is an option.

Budget set approximate, offer your assessment

It would be nice for you to see how works for example http://www.cart-sms.com/ru/index.html (for openCart) and offer a version of execution for us

In addition to the development, it will be necessary to make documentation for the developer on the use of
The code should be with detailed comments
Instructions for developer to integrate into the system