Intermittent 5s Timeout on Supabase Custom Auth Hook (signup): Email Sent, Signup Fails
auth🟡javascriptI'm running into a weird issue with a custom Supabase Auth hook for sending signup emails. Occasionally, when a user signs up, the form shows a Error running hook URI server error and the logs state:
The user still gets the verification email (though the link doesn't work, since the signup didn't complete). My code[1] is very similar to the example from the docs [2}.
Some details:
* The function is small (~50KB bundle), only imports what’s needed (React Email, Resend, etc).
* Boot time is always fast (200–500ms).
* The error only happens on
* The Resend API isn’t the issue. The email is always sent, even when the error happens.
* Timing logs show no single step is consistently slow.
* The error is always a 5s timeout from Supabase’s side.
What I've tried:
* Checked bundle size and dependencies (all minimal).
* Added timing logs—no obvious bottleneck.
* Boot time is always fast
Questions:
* Has anyone else seen this with custom auth hooks?
* Any tips for debugging or avoiding these timeouts?
* Is there a way to get more granular logs or see what’s happening inside Supabase during these failures?
Any help or ideas would be much appreciated!
[1]: https://github.com/dnywh/peels/blob/2cd8e188f37adb8bf893d5fb05cb31ca1d55241b/supabase/functions/send-email-for-auth-action/index.ts#L100C7-L116C9
[2]: https://supabase.com/docs/guides/functions/examples/auth-send-email-hook-react-email-resend
422: Failed to reach hook within maximum time of 5.000000 secondsThe user still gets the verification email (though the link doesn't work, since the signup didn't complete). My code[1] is very similar to the example from the docs [2}.
Some details:
* The function is small (~50KB bundle), only imports what’s needed (React Email, Resend, etc).
* Boot time is always fast (200–500ms).
* The error only happens on
email_action_type === "signup"* The Resend API isn’t the issue. The email is always sent, even when the error happens.
* Timing logs show no single step is consistently slow.
* The error is always a 5s timeout from Supabase’s side.
What I've tried:
* Checked bundle size and dependencies (all minimal).
* Added timing logs—no obvious bottleneck.
* Boot time is always fast
Questions:
* Has anyone else seen this with custom auth hooks?
* Any tips for debugging or avoiding these timeouts?
* Is there a way to get more granular logs or see what’s happening inside Supabase during these failures?
Any help or ideas would be much appreciated!
[1]: https://github.com/dnywh/peels/blob/2cd8e188f37adb8bf893d5fb05cb31ca1d55241b/supabase/functions/send-email-for-auth-action/index.ts#L100C7-L116C9
[2]: https://supabase.com/docs/guides/functions/examples/auth-send-email-hook-react-email-resend
