At this time the REST API included with the official release of EE4 does not have write endpoints, however there is a branch that has the write endpoints that can be used for testing and development. You can use this branch available on Github:
The support post ‘Registration api – how can I register in an event using rest api’ is closed to new replies.
Have a question about this support post? Create a new support post in our support forums and include a link to this existing support post so we can help you.
Support forum for Event Espresso 3 and Event Espresso 4.