JWT デバッガー

使い方

1. Paste a JWT — the three dot-separated segments (header, payload, signature) are split automatically.
2. The Base64URL header and payload are decoded into readable JSON.
3. Registered claims such as exp, iat, and nbf are rendered as human-readable dates next to their raw epoch values.
4. Decoding happens entirely in your browser; the signature is not verified and the token never leaves your machine.

例

• Paste a token like eyJhbGciOiJIUzI1NiJ9.eyJzdWIiOiIxMjMiLCJleHAiOjE3MDAwMDAwMDB9.abc and the payload reveals sub: 123 and exp: 1700000000, shown as a readable UTC date.
• If the exp claim is in the past, the tool flags the token as expired so you can spot stale credentials at a glance.