400 error if user is not in channel for check if member

According to the API docs, “check if member” should return a JSON response of { is_member: <boolean> }. When I make this call with a user who is present in the channel, I am receiving { is_member: true, "state"=>"joined" } as expected. However, if I provide a user who is not present, I get a 400 error with the message "User" not found instead of the expected 2xx with { is_member: false }.

Here’s the URL I’m hitting (with sensitive keys redacted):


(I’ve tried passing UUIDs instead of not-in-the-channel as well just in case it was a string formatting issue, but no luck.)

For now I’m going to rescue the 400 error and return false, but curious if the docs are incorrect or if I’m missing something.


  • Kyle