JWT Online Debugger & Decoder

Decode JSON Web Token headers and payloads with automatic validity and expiration countdown

100% ブラウザローカル処理: クラウド送信ゼロ - オフライン対応

JWT 除錯驗證 100% ブラウザローカル処理

JWT トークンを入力 (ドット区切りの3部構成)

Header.Payload.Signature

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkFsZXgiLCJpYXQiOjE1MTYyMzkwMjJ9.XbPfbIHMI6arZ3Y922BhjWgQzWXcXNrz0ogtVhfEd2o

ヘッダー (Header)HS256

{
  "alg": "HS256",
  "typ": "JWT"
}

ペイロード (Payload)

発行日時 (iat): 1/18/2018, 1:30:22 AM

{
  "sub": "1234567890",
  "name": "Alex",
  "iat": 1516239022
}

署名 (Signature)

HMAC-SHA256 (base64url): XbPfbIHMI6arZ3Y922BhjWgQzWXcXNrz0ogtVhfEd2o

Offline client-side JWT parser. Decode header, payload claims, and check expiration (exp) and issued-at (iat) timestamps securely.

よくある質問

Is it safe to paste JWT tokens into this online tool?

Completely safe. Processing happens entirely in your local browser window without transmitting tokens to any server.

How does the tool check token expiration?

It parses exp and nbf timestamp claims and compares them to your current UTC system clock.