JWT DecoderJWT 解码

Decode a JSON Web Token locally, no upload.

在浏览器本地解码 JSON Web Token 的 Header 与 Payload，不发送令牌、不验证签名。

What is JWT Decoder?JWT 解码 是什么？

A JWT decoder splits a JSON Web Token into its three parts — header, payload and signature — and shows the header and payload as readable JSON. It reveals the algorithm, issuer, expiry and custom claims, which makes it the fastest way to debug authentication. Decoding happens entirely locally, so tokens containing real session data never leave your browser.

JWT 解码器把 JSON Web Token 拆成三部分——头部、载荷、签名——并把头部和载荷显示为可读 JSON。它能揭示算法、签发者、过期时间和自定义声明，是调试认证问题最快的方式。解码完全在本地进行，含真实会话数据的令牌不会离开浏览器。

How to use jwt decoder如何使用 JWT 解码

1. Paste the complete JWT, including the three dot-separated segments.
2. Read the decoded header (algorithm and token type) and payload (claims).
3. Check the exp claim to see whether the token has already expired.
4. Copy any section. The signature is displayed but not verified, because verification needs the secret or public key.

1. 粘贴完整 JWT，包含三个由点分隔的部分。
2. 阅读解码出的头部（算法与令牌类型）和载荷（声明）。
3. 查看 exp 声明判断令牌是否已过期。
4. 复制任意部分。签名仅展示不验证，因为验证需要密钥或公钥。

Common uses常见用途

• Debug why an API call returns 401 by inspecting the token expiry
• Check which claims and scopes a token actually carries
• Confirm the signing algorithm before troubleshooting a verification failure
• Inspect tokens copied from browser dev tools, logs or a support ticket

• 接口返回 401 时，查看令牌过期时间定位原因
• 确认令牌实际携带了哪些声明和权限范围
• 排查验签失败前，先确认签名算法
• 检查从浏览器开发者工具、日志、工单里复制的令牌

FAQ常见问题