HumanFlow has a REST API and an MCP connector. Both are in private beta, which means the documentation is public and the endpoints are not.
The API exposes two authenticated POST endpoints: one to rewrite text, one to score it sentence by sentence. It is billed by words rather than by request, and the plan structure is published so you can estimate a bill before committing to anything.
The MCP connector is for using HumanFlow from inside an MCP-aware client such as Claude or Cursor — rewriting or scoring what your assistant just produced without leaving the conversation. The connector URL is published on the MCP page, and it does not currently accept connections.
There is no self-serve signup for either. Access is arranged by email, and the same account covers both when it opens.
Being straightforward about the state of this: several competitors ship live public APIs today, and our comparison pages say so. If you need to build against a humanizer this quarter, one of them is the working choice and we would rather tell you that than have you wait.
To join the beta, email support@humanflow.pro with what you are building. A test key and a realistic date is what you will get back.
Pricing for the API is published separately from the app plans, because the two are metered differently — the app bills monthly words to a person, the API bills volume to a machine. Keeping them in separate places is deliberate: it stops an API rate being quoted on a page about the app.