A JSON Web Token (JWT) is a compact, URL-safe way to represent claims between two parties. It consists of three Base64URL-encoded parts — header, payload, and signature — separated by dots.

Is it safe to decode a JWT online?

Yes — on snaptxt.app, decoding happens entirely in your browser using JavaScript. Your token is never sent to any server.

What algorithms does the JWT Generator support?

HS256, HS384, HS512 (HMAC), RS256, RS384, RS512 (RSA), and ES256, ES384 (ECDSA). You can also generate RSA and EC key pairs in-browser.

What's the difference between decoding and verifying a JWT?

Decoding reads the header and payload without checking the signature. Verification checks the signature against a secret or public key to confirm the token hasn't been tampered with.

Only if the payload includes an exp (expiration) claim. Without it, the token is valid indefinitely — usually a bad practice outside of testing.

JSON Web Tokens

JWT Decoder & Generator

Free online tools to decode, inspect, and sign JSON Web Tokens. Everything runs in your browser — your tokens never leave your device.

JWT Decoder

Paste any JWT to instantly inspect its header, payload, claims, and expiry. Optional on-device AI explains what the token grants in plain English.

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JWT Generator

Sign tokens with HS256, RS256, ES256, and more. Build the payload visually, set expiry, and generate RSA or EC key pairs — all in-browser.

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Tokens never leave your browser Instant, no sign-up

What is a JSON Web Token?

A JSON Web Token (JWT) is a compact, URL-safe string used to securely transmit information between two parties. It is widely used for authentication and authorization in web applications and APIs.

A JWT is made up of three Base64URL-encoded parts separated by dots:

1Header — the token type and signing algorithm (e.g. HS256, RS256).
2Payload — the claims: who the token was issued to, what it grants, and when it expires.
3Signature— a cryptographic signature that proves the token hasn't been tampered with.

When do developers use JWTs?

Authentication — issued on login, sent with each API request as a Bearer token.
Authorization — encodes roles and permissions so APIs can gate access without a database lookup.
Information exchange — passes signed data between microservices that need to trust the source.
Single sign-on (SSO) — lets users authenticate once and access multiple services.

Frequently asked questions

What is a JWT?: A JSON Web Token (JWT) is a compact, URL-safe way to represent claims between two parties. It consists of three Base64URL-encoded parts — header, payload, and signature — separated by dots.
Is it safe to decode a JWT online?: Yes — on snaptxt.app, decoding happens entirely in your browser using JavaScript. Your token is never sent to any server.
What algorithms does the JWT Generator support?: HS256, HS384, HS512 (HMAC), RS256, RS384, RS512 (RSA), and ES256, ES384 (ECDSA). You can also generate RSA and EC key pairs in-browser.
What's the difference between decoding and verifying a JWT?: Decoding reads the header and payload without checking the signature. Verification checks the signature against a secret or public key to confirm the token hasn't been tampered with.
Do JWTs expire?: Only if the payload includes an exp (expiration) claim. Without it, the token is valid indefinitely — usually a bad practice outside of testing.

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