JWT Decoder
Decode JSON Web Tokens and inspect header, payload, and expiry claims instantly in your browser
JWT Decoding Tips
- A JWT is three Base64URL-encoded parts joined by dots: header.payload.signature.
- Decoding only reveals the contents — the signature is not verified without the secret key.
- Never paste production tokens into tools that run on a server. This decoder runs 100% in your browser.
- The exp claim is a Unix timestamp in seconds; this tool converts it to your local time automatically.
プロフェッショナルな JWT Decoder 処理機能
JWT Decoder データを効率的かつプロフェッショナルに扱うために必要なすべて
Structure Validation
Instantly checks the header.payload.signature format and reports malformed tokens with a clear error message.
Formatted JSON Output
Decoded header and payload are pretty-printed with two-space indentation, ready to read or copy.
Expiry Panel
exp, iat, and nbf claims are converted to your local time with a valid/expired badge at a glance.
UTF-8 Safe
Non-ASCII claim values such as names in other languages decode correctly thanks to proper UTF-8 handling.
Instant Decoding
Long-lived access tokens and refresh tokens decode in milliseconds with zero network activity.
Zero Setup
No installs, no accounts, no extensions. Open the page, paste, and decode.
仕組み
JWT Decoder をプロのように処理する簡単なステップ
Paste Your Token
Copy the JWT from your request header, cookie, or logs and paste it into the input area.
Click Decode
The header and payload are Base64URL-decoded and formatted as JSON instantly.
Inspect the Claims
Read the algorithm, subject, scopes, and the expiry panel showing whether the token is still valid.
Copy & Continue
Copy the decoded payload JSON for debugging, documentation, or support tickets.
プロフェッショナルな JWT Decoder フォーマッター＆バリデーター
世界中の何百万もの開発者に信頼される JWT Decoder 処理
エキスパートによる構築
Our JWT decoder implements the RFC 7519 structure directly in your browser: it splits the JWS compact serialization, Base64URL-decodes the header and payload, and renders the claims as formatted JSON. The expiry panel turns raw Unix timestamps into your local time so you can tell at a glance whether a token is still valid.
主な技術的特徴:
- • Full Base64URL decoding with proper UTF-8 and padding handling
- • Human-readable expiry panel for exp, iat, and nbf claims
- • Instant formatting of decoded header and payload JSON
- • Client-side processing - tokens never leave your device
- • Supports HS256, RS256, ES256 and all other JWS algorithms
信頼とセキュリティ
Trusted by developers who handle authentication daily. Because decoding happens entirely on your machine, access tokens, refresh tokens, and ID tokens are never transmitted anywhere — which is exactly how a JWT inspector should work.
セキュリティとプライバシー:
- • 100% client-side decoding - no server uploads, ever
- • No tracking, cookies or token logging
- • HTTPS encryption for secure connections
- • Signature is displayed but never verified remotely
- • GDPR and CCPA compliant approach
プロがEZ Formatterを選ぶ理由
日常の開発ワークフローに JWT Decoder フォーマッターを信頼する何百万もの開発者に参加してください。登録不要、完全無料、プライバシーを考慮して構築されています。
よくある質問
Jwt Decoder フォーマットに関するよくある質問
Yes, it is completely free with no registration required. All decoding happens in your browser.
No. Decoding is not verification: without the secret or public key, a signature cannot be checked. This tool shows the signature as-is so you can inspect it, but treats the claims as unverified data, which is the correct behavior for a client-side decoder.
Never. The decoder is plain JavaScript running on this page. Your token is not transmitted, logged, or stored — close the tab and it is gone.
The exp, iat, and nbf claims are Unix timestamps in seconds, converted to your local timezone. If the result looks wrong, check that your device clock and timezone are set correctly.
Unsigned tokens with alg "none" decode fine. Encrypted JWE tokens (five-part tokens) are not supported, since decryption requires the key.