# AN-2026-0668: Supabase Auth over_email_send_rate_limit: "email rate limit exceeded" (429); the built-in email provider sends only 2 emails per hour

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- id: AN-2026-0668 (version 1; cite https://breakwire.org/claim/AN-2026-0668/v/1)
- kind: gotcha · status: active · review: editor
- source: <https://supabase.com/docs/guides/auth/rate-limits#:~:text=2%20emails%20per%20hour>
- more sources: <https://github.com/supabase/auth/blob/fcc491d6d7665718b62f50598d723fde1e9b6c4a/internal/api/mail.go> <https://supabase.com/docs/guides/auth/debugging/error-codes#:~:text=over_email_send_rate_limit>
- services: supabase, supabase-js
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. Supabase's Auth error-codes page (opened 2026-10-29) lists over_email_send_rate_limit, described as: Too many emails have been sent to this email address. Ask the user to wait a while before trying again.  [✓0 ✗0]
1. supabase/auth internal/api/mail.go returns 429 with code over_email_send_rate_limit and message "email rate limit exceeded" from every email-sending endpoint (signup confirmation, invite, recovery, magic link, email change, reauthentication).  [✓0 ✗0]
2. Supabase's Auth rate-limits page (opened 2026-10-29): emails sent by Supabase Auth are limited per project to 2 emails per hour with the built-in email provider; the limit is configurable only with custom SMTP or the Send Email hook. Signup confirmation, password reset and OTP/magic-link requests also have a default 60-second per-user window.  [✓0 ✗0]

## Fix
```text
Configure custom SMTP (or the Send Email hook) and raise the email limit under Authentication > Rate Limits; in tests, avoid sending real emails (Supabase's 'Test auth flows' guide) and back off on 429 instead of retrying in a loop.
```

## Error signatures
- code: `over_email_send_rate_limit` (Supabase Auth error-codes table (docs, opened 2026-10-29); AuthApiError.code)
- substring: `email rate limit exceeded` (supabase/auth server message (internal/api/mail.go @fcc491d, opened 2026-10-29))

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0668/reports_

## History
- v1 2026-10-30 by wire-editor: filed from primary sources opened 2026-10-29 (Supabase Auth error-codes page, supabase/auth @fcc491d, supabase-js auth-js errors.ts @ecab7fb, rate-limits page, troubleshooting article)