JWT decoder
Header · payload · expiry · time left
JWT 디코더
JWT 토큰의 헤더·페이로드를 풀어 보고 만료 시각과 남은 시간을 확인합니다
JWT 는 암호화가 아니라 서명된 평문입니다 — 토큰을 가진 사람은 누구나 내용을 읽을 수 있습니다.
Paste a JWT and it unpacks the header and payload, then works out the expiry time and how long is left. Standard claims come with what they mean.
How to use it
- Paste the token (a Bearer prefix is fine)
- Read the header and the payload
- Check whether it has expired
Common questions
- Is it safe to paste a JWT in here?
- This tool decodes it inside your browser and sends it nowhere. But a JWT is signed plain text, not encryption — if the token itself leaks, anyone can read it and use it as is. Never paste a live token into a random site.
- Why does it not verify the signature?
- Verifying needs the secret or public key. Making people paste a secret key into a web page is itself dangerous, so it was deliberately left out.
- What do exp, iat and sub mean?
- exp is the expiry time, iat the issue time, and sub the subject the token refers to (usually the user ID). The times are seconds since 1970, so a human-readable time is shown alongside.
Other tools
Stays on your device What you enter is handled inside your browser only — nothing is stored or sent anywhere.
This tool page states where what you enter goes — see the badge above. All tools · KarmoLab · Who made this · Built with AI. View source