The APIs can be used for several things, at varying technical levels.
The easiest API to use are the custom players. This will allow you to use JWPlayer, Flowplayer and more with DaCast content inside. These are as simple to use as replacing the IDs in the player with those that are associated with your account. Here are two shortcut modules to explain this better:
These use the base version of both player. On the more advanced side, you can also generate a token to use in a customized JWplayer, or use a totally different player as well. This page describes the token process for this:
Inside your DaCast account, there are additional APIs to use with CMS' and to help develop your own site based around Dacast. The CMS use Drupal as their base. These are found inside your account after you create an API Key and are advanced.
You can find all the documentation on API here: https://api.dacast.com/v2/doc