Content validator against profanity & obscenity.
PurgoMalum API is a free Data Validation API that requires no API key, is only available over HTTP and has unconfirmed CORS support.
Details from purgomalum.com.

Unified API suite · now live
Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
US address standardization, congressional and state legislative districts, Census data; free tier
The PurgoMalum API is provided by PurgoMalum (purgomalum.com).
Yes. The PurgoMalum API is listed in the Data Validation category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
No. The PurgoMalum API requires no authentication, so you can start making requests without signing up.
CORS support for the PurgoMalum API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
No. The PurgoMalum API is only available over plain HTTP, which browsers block on HTTPS sites. Call it from a server instead.