Topic: jwt

• Base64 variants: standard vs URL-safe alphabets, padding rules and decoder strictness

  RFC 4648 defines both the standard and URL-safe base64 alphabets and requires padding by default, but JWTs explicitly omit it, MIME wraps lines at 76 characters while GNU base64 needs -w0 to stop doing the same, and decoders from Python to the browser disagree on whether stray characters and missing padding are errors.

  article · en · reviewed · knowledge as of 2026-09-25

Machine-readable: JSON