Free JWT Decoder Online
Decode JSON Web Tokens (JWT) instantly in your browser. View the header, payload, and signature — everything runs 100% client-side for maximum privacy.
JWT Decoder
JWT FAQ
What is a JWT?
A JSON Web Token (JWT) is a secure way to transmit information between parties, consisting of a header, payload, and signature.
Is it safe to decode JWTs online?
Yes, if decoding happens locally in your browser (like this tool). The token never leaves your device.
Can I verify a JWT with this tool?
No. This tool only decodes JWTs. Always verify authenticity in your backend using the correct secret or public key.
What are JWTs used for?
JWTs are commonly used for authentication, authorization, and secure information exchange in modern web apps.
About JSON Web Tokens (JWT)
A JSON Web Token (JWT) is a compact, URL-safe standard for securely transmitting information between parties. They are heavily used in authentication systems, API authorization, and distributed architectures where stateless security is required.
Structure of a JWT
A JWT consists of three Base64URL-encoded parts separated by dots:
xxxxx.yyyyy.zzzzz
- Header — metadata like algorithm (
HS256,RS256). - Payload — claims like user ID, roles, or expiration.
- Signature — cryptographic proof of integrity.