OAuth PKCE Generator — Create Secure Code Verifiers and Challenges
Generate RFC 7636 PKCE code verifier and challenge pairs for OAuth 2.0 authorization code flow. Choose verifier length, get the SHA-256 code challenge, and see exactly where each value goes in the auth URL and token exchange request.
How to Use OAuth PKCE Generator — Create Secure Code Verifiers and Challenges
How to Use the OAuth PKCE Generator
Step 1: Set Verifier Length
Adjust the slider to choose a code verifier length between 43 and 128 characters. RFC 7636 requires at least 43 characters — 64 is a safe default for most use cases.
Step 2: Generate
Click Generate PKCE Pair. The tool instantly computes:
- code_verifier — a cryptographically random string from the URL-safe unreserved character set (A-Z a-z 0-9 - . _ ~)
- code_challenge — BASE64URL(SHA-256(code_verifier))
- code_challenge_method — always
S256
Step 3: Use in Your OAuth Flow
Authorization request — add these query parameters to your authorization URL:
code_challenge=<value>
code_challenge_method=S256
Token exchange — include in the POST body:
code_verifier=<value>
Step 4: Copy
Use individual copy buttons next to each field, or click Copy All to get all three values as key=value pairs.
Security Notes
- Never include the
code_verifierin the authorization URL — it must only be sent at token exchange - Generate a fresh PKCE pair for every authorization request
- Store the
code_verifierin session storage or memory, not in cookies or URL params
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