
Data about Meetups from Meetup.com.
Meetup.com API is a free Social API that requires apiKey authentication, is served over HTTPS and has unconfirmed CORS support.
Details from meetup.com.

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The Meetup.com API is provided by Meetup (meetup.com).
Yes. The Meetup.com API is listed in the Social 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.
Yes. The Meetup.com API uses apiKey authentication, so you need to register for credentials before making requests.
CORS support for the Meetup.com API is unknown. Test a request from the browser, and fall back to a server-side call if it is blocked.
Yes. The Meetup.com API is served over HTTPS, so it's safe to use in production.