🎫 JWT Decoder
Decode a JWT header and payload, with expiry check.
🔒 Everything runs locally in your browser. Files and content are never uploaded.
About this tool
只做 Base64URL 解码和 JSON 格式化，**不验证签名**——签名验证需要密钥，绝不该在网页里做。如果 token 里有过期时间（exp），会直接标出还剩多久或多早之前就过期了。