Underscores in OAuth Callback URL?

[ChrisUM]

I just spent a while debugging a problem where my OAuth process would fail when I used a callback URL in the format my_app://fitbit/auth

Removing the underscore immediately fixed the issue. Is an underscore a valid character in the URL? If not can you please validate URLs that are entered when creating an app to prevent other users from having the same issue?

[JohnFitbit]

Hi @ChrisUM,

Welcome to the forums!

Out of curiosity, can you explain further as to what you mean by the oAuth process failing when you had an underscore in your callback URL? Were you receiving an error? If so, what were the code and messages? Could you also provide me with your callback URL with the underscore?

I hope to hear from you soon. Let me know if you have any additional questions.

[ChrisUM]

I created an app with a callback URL of:

social_rhythm://fitbit/auth

When using this for authentication in my iOS app it fails by going to a Fitbit 404 page every time before the user even has the chance to select their permissions options. Changing this callback to:

socialrhythm://fitbit/auth

With no other changes allowed the process to continue normally. Searching on the internet I found another users that had a similar issue when working within Unity, but no mention of it otherwise.

[JohnFitbit]

Hi @ChrisUM,

Thanks for sharing that info. I'll reach out to the team and confirm if this is expected behavior. I'll follow up once I get more information.

Let me know if you have any questions in the meantime.