base64url
What this is
RFC 4648 §5 defines base64url. Tokens travel in query strings and headers, so + / = are replaced. The JWT tool is three base64url segments; this page is the primitive underneath.
Open the encoder — UTF-8 and base64url, no upload.
FAQ
- Need padding?
- JOSE omits padding. Some libraries still require =. This decoder adds padding before atob.