A JWT (JSON Web Token) is a compact, URL-safe token format for securely transmitting information between parties. It consists of three parts: header (algorithm), payload (claims/data), and signature. JWTs are the standard for API authentication.

Is it safe to decode a JWT?

Decoding a JWT reveals its contents but does not compromise security — the payload is base64-encoded, not encrypted. The security lies in the signature verification. However, never expose JWTs containing sensitive data in URLs or client-side logs.

Claims are statements about the user and metadata. Standard claims include: iss (issuer), sub (subject), exp (expiration), iat (issued at), and aud (audience). Custom claims can contain any application-specific data like user roles.

How long should a JWT token last?

Access tokens should expire in 15-30 minutes for security. Refresh tokens can last 7-30 days. Short-lived access tokens limit damage if compromised, while refresh tokens provide a smooth user experience without frequent re-authentication.

Onko JWT:n purkaminen tällä sivulla täysin turvallista?

Kyllä on. Purku tapahtuu 100% selaimesi sisällä JavaScriptillä. Sinun herkkää tokeniasi ei lähetetä meidän saatikka kenenkään muunkaan palvelimelle.

Mistä JWT tietää milloin se ei ole enää voimassa?

Hyötykuorman kenttä 'exp' on aikaleima joka määrittää varmenteen vanhenemisajan. Palvelimen tehtävänä on estää pääsy tämän ajan ylittämisen jälkeen.

🎫 JWT-dekooderi

Pura JSON Web Tokens (JWT) tarkastellaksesi otsikkoa (header), hyötykuormaa (payload) ja allekirjoitusta.

Decodes JSON Web Tokens showing header, payload, and signature without requiring the secret key, for debugging auth flows.

Key Facts

Standardized in RFC 7519 (2015)
80%+ of modern APIs use JWT
Three parts separated by dots (.)
Common algorithms: HS256, RS256

Frequently Asked Questions

What is a JWT?

Compact, URL-safe token with header (algorithm), payload (claims), and signature for API authentication.

Is decoding JWT safe?

Yes — payload is base64-encoded, not encrypted. Security is in signature verification, not content hiding.

What are JWT claims?

Statements about user: iss (issuer), sub (subject), exp (expiration), iat (issued at), aud (audience).

How long should JWT last?

Access tokens: 15-30 min. Refresh tokens: 7-30 days. Short-lived limits damage if compromised.

🎫 JWT-dekooderi

Mikä on JSON Web Token (JWT)?

JWT:n Rakenne

Kysymyksiä ja Vastauksia

Key Facts

Frequently Asked Questions

🎫 JWT-dekooderi

Mikä on JSON Web Token (JWT)?

JWT:n Rakenne

Kysymyksiä ja Vastauksia

Key Facts

Frequently Asked Questions

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