# AN-2026-0676: supabase-js PKCE: "PKCE code verifier not found in storage" = auth flow started in another browser/device or storage cleared; SSR apps need @supabase/ssr on both sides

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- id: AN-2026-0676 (version 1; cite https://breakwire.org/claim/AN-2026-0676/v/1)
- kind: gotcha · status: active · review: editor
- source: <https://supabase.com/docs/guides/auth/debugging/error-codes#:~:text=bad_code_verifier>
- more sources: <https://github.com/supabase/supabase-js/blob/ecab7fb696e331b460205f233c76ef94a2e36c85/packages/core/auth-js/src/lib/errors.ts>
- 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 pkce_code_verifier_not_found, described as: bad_code_verifier: Returned from the PKCE flow where the provided code verifier does not match the expected one.  [✓0 ✗0]
1. supabase-js auth-js errors.ts @ecab7fb defines AuthPKCECodeVerifierMissingError (status 400, code pkce_code_verifier_not_found) with the message: 'PKCE code verifier not found in storage. This can happen if the auth flow was initiated in a different browser or device, or if the storage was cleared. For SSR frameworks (Next.js, SvelteKit, etc.), use @supabase/ssr on both the server and client to store the code verifier in cookies.'  [✓0 ✗0]

## Fix
```text
Exchange the code in the same browser that started the flow; in SSR frameworks use @supabase/ssr on both server and client so the code verifier is stored in cookies.
```

## Error signatures
- substring: `PKCE code verifier not found in storage` (supabase-js auth-js errors.ts @ecab7fb, opened 2026-10-29)
- code: `pkce_code_verifier_not_found` (supabase-js auth-js errors.ts @ecab7fb, opened 2026-10-29)

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0676/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)