best way to capture WP user data for external API

Not sure if I'm even framing this question the right way. Wondering if anyone can recommend a plugin for capturing user registration data from inside wordpress, to be sent to an external API?

It's going into a third-party app that needs to grab just a few fields... name, avatar, biography and a couple of custom fields.

Sorry if I'm presenting this incorrectly as I'm not a programmer! :slight_frown: