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PKCE Verifier

Generate PKCE code_verifier and code_challenge (S256) pairs, or verify that a verifier matches a challenge. Test mobile and SPA auth flows safely — free, local, no signup.

100% Local Browser Native

How to Use the PKCE Verifier

1. Paste source for PKCE Verifier

Paste source for PKCE Verifier into the input area. Nothing runs until you trigger it.

2. Verify

Run verification and read the verdict.

3. Test the real flow

Take the pair into your OAuth authorize + token calls and confirm the exchange.

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Frequently Asked Questions

What is PKCE?

PKCE (Proof Key for Code Exchange) is a security extension to OAuth 2.0 that prevents authorization code interception attacks. Used with public clients like mobile and SPA apps.

When do I use code_verifier vs code_challenge?

Generate a code_verifier (random string) and its code_challenge (SHA-256 hash). Send the challenge in the authorization request, then send the verifier during token exchange.

Does it support S256 only?

Yes. S256 (SHA-256) is the only supported method. It's the recommended and most secure option per the PKCE RFC specification.

Can I verify an existing pair?

Yes. Paste a code_verifier and code_challenge to verify they match. The tool recalculates the challenge from the verifier and compares them.

Is generation done locally in PKCE Verifier?

Yes. All PKCE generation and verification happens in your browser. No data is transmitted to any server.

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Last updated October 2026