I'd like some help confirming which URLs to use. Quickbooks Online no longer supports OAuth 1 for new accounts and OAuth 2 documentation seems a bit disorganized and confusing. To top it all off, in the past few days I've seen a lot of vague errors from the API and it seems that there was some scheduled maintenance but even though all systems are operational I'm still seeing a message saying "We are temporarily unavailable due to scheduled maintenance."
I've been trying to test the initial step by just pasting a URL into a browser to get an authorization code. Here is my URL verbatim except for a fake client_id and a fake ngrok subdomain:
The response currently gives me a pretty yellow post-it note with "We'll be back soon" on it. I know that seems obvious but the Intuit status page shows green on everything. In the event that it really is down, it'd still be helpful if someone can confirm that this is the correct URL to use because I noticed that neither one of the "discovery" documents has this URL but after banging my head against a wall a few days ago I realized the discovery documents could be incorrect so I switched to trying the sandbox URL.
Is that correct or is the base URL supposed to be something else such as
https://appcenter.intuit.com/connect/oauth2
https://oauth.intuit.com/oauth/v1/get_request_token
even in dev mode?
I'm very surprised that there is not a detailed language-agnostic REST client step-by-step example for OAuth2 with the Quickbooks Online API. Someone commented that Intuit must feel that showing how to generate the signature is too complex and everyone should just use an SDK, but none of the SDKs are an option for me.
Thanks for any help!