JWT 解码器
解码 JSON Web Token，查看其 Header 和 Payload 中的声明字段。解码在本地完成，Token 不会离开页面。
如何使用此工具
- 1将 JWT 粘贴或输入到上方输入框。
- 2解码结果即时刷新显示。
- 3一键复制输出内容。
常见问题
用这个工具解码敏感 JWT 数据安全吗？+
安全。所有处理均通过 JavaScript 在浏览器本地完成，您的输入不会上传或存储到任何服务器。
我的数据会被保存吗？+
不会。该工具完全在浏览器中运行，您粘贴或输入的内容不会上传到服务器。
教程与深度解析
JWTs Explained: Header, Payload, Signature and Security Pitfalls
Learn how JSON Web Tokens work — the three parts, signing vs encryption, the alg=none attack, cookie vs localStorage, and expiry claims — with worked examples.
Common JSON Errors and How to Fix Them
Trailing commas, single quotes, unquoted keys, BOM, NaN — learn what breaks JSON and how to fix each error fast with a free online formatter.
Base64 Explained: What It Is and When to Use It
Learn what Base64 encoding is, why it adds 33% overhead, how data URIs work, the base64url variant, and exactly when to encode or decode — with worked examples.
MD5 vs SHA-256: Which Hash Should You Use?
MD5 is broken for security but fine for checksums. SHA-256 is the modern default. Learn the difference, when each applies, and how to hash passwords safely.