Can I send HTML or text directly to Extract APIs?

Yes. All Extract APIs support the POSTing of content for analysis and content extraction.

The Article API supports both plain-text and HTML POSTs, whereas all other APIs support POSTing of HTML.

When POSTing content to Extract APIs, the url value is still required in your request URL. Diffbot will attempt to resolve any relative links contained in your POSTed markup. If you do not wish this to occur, you may send a spurious url value.

Read more on extracting content not available online.