JWT Token Decoder & Validator

Decode any JWT and catch dangerous tokens instantly

JWT Token Decoder & Validator splits any JWT into its header and payload, base64url-decodes and pretty-prints both, and evaluates the exp/iat/nbf time claims into plain-English statuses like "expired 3 hours ago". It also flags the well-known "alg":"none" vulnerability and validates structural well-formedness, showing clear errors for malformed tokens without ever sending your data anywhere.

• →Base64url-decodes header and payload, handling the URL-safe charset and missing padding correctly
• →Converts exp / iat / nbf claims to your local timezone with human-readable status text
• →Flags "alg":"none" tokens as a critical security warning — a well-known real-world JWT vulnerability
• →Validates exactly 3 dot-separated segments and valid JSON in each, with clear non-crashing errors for malformed input
• →Watermarked by Cikal Studio Labs · Works on any device, no install required