Base64URL Converter
Bidirectional conversion between base64url, base64 (standard), hex, and UTF-8 text. base64url is the form WebAuthn / JOSE / CTAP2 use everywhere.
Input
All representations
Paste a value to convert.
All decoding runs locally.
About base64url
base64url is the URL- and filename-safe variant of base64 (RFC 4648 §5). It replaces + with - and / with _, and drops trailing = padding. WebAuthn, JOSE (JWT/JWS/JWE), and CTAP2 use it for every binary field.
Spec
RFC 4648 §5.
Use
WebAuthn challenge, credentialId · JWS signatures · CTAP2 messages · OAuth2 PKCE.