🔑 JWT 디코더

JSON 웹 토큰 디코딩 - 헤더, 페이로드, 만료 확인

🔒 이미지가 기기 밖으로 나가지 않아요. 모든 처리는 JavaScript Base64 decoding를 사용하여 브라우저에서 로컬로 이루어져요. 업로드, 서버, 추적이 없어요.

기능

  • Full Token Inspection — Decode and display the header, payload, and signature of any JWT token.
  • Expiration Check — See issued-at and expiration timestamps with human-readable dates and expiry status.
  • Claims Display — View all standard claims — issuer, subject, audience, and custom fields.
  • Fully Offline — Decoding happens in your browser. Your tokens are never sent to any server.

작동 방식

  1. Paste your JWT — Paste a JSON Web Token in the input field.
  2. Inspect the decoded parts — View the header (algorithm, type), payload (claims, timestamps), and signature.
  3. Check expiration — See whether the token is still valid or has expired.

활용 사례

  • Debug authentication issues by inspecting JWT claims
  • Verify token expiration and issuer before trusting it
  • Inspect tokens during API development and testing
  • Learn about JWT structure by examining real tokens

자주 묻는 질문

Does this verify the JWT signature?

This tool decodes the token to show its contents. Signature verification requires the secret key or public key, which we don't collect for privacy reasons.

Is it safe to paste my JWT here?

Yes. Everything runs locally in your browser. Your token is never sent to any server or stored anywhere.

What JWT formats are supported?

Standard three-part JWTs (header.payload.signature) using Base64URL encoding. This covers JWTs from all major identity providers.

관련 도구