OAuth PKCE Generator

Generate PKCE code verifier and S256 code challenge

PKCE (RFC 7636) protects OAuth authorization-code flows for public clients. You generate a high-entropy code_verifier, hash it with SHA-256, and send the URL-safe Base64 digest as code_challenge with code_challenge_method=S256. Later, the token request includes the original verifier so the server can confirm the same party started and finished the flow.

Verifier rules

• Length between 43 and 128 characters after encoding.
• Characters limited to unreserved URI characters: [A-Z] [a-z] [0-9] - . _ ~.
• Use S256 unless your identity provider documents another method.

Pair with OAuth Authorization URL Builder when crafting authorize links.