JWT Encoder & Decoder – Debug JSON Web Tokens

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Encode, decode, and verify JSON Web Tokens with HMAC SHA-256/384/512 signature support. Validates exp, nbf, and iat claims — fully browser-side.

JWT Encoder & Decoder

Create, verify, and debug JSON Web Tokens

Token Builder

Algorithm

Header

Payload

Secret key *

Never share your secret key. Keep it secure server-side.

Output

No token yet

Fill in the fields and click Generate JWT

What is JWT Encoder & Decoder?

Create or decode JWTs with custom headers and payloads. Verify HMAC SHA-256/384/512 signatures and validate expiration, not-before, and issued-at timestamps. Uses Web Crypto API — nothing leaves your browser.

jwtjson web tokendecoderencoderauthenticationhmac

JWT Encoder & Decoder Features

Signature Verification

Verify HS256, HS384, HS512 signatures with your secret.

Claims Validation

Auto-checks exp, nbf, and iat timestamps.

JWT Encoder & Decoder FAQ

All processing uses the browser's Web Crypto API — tokens never leave your device. Still, avoid pasting tokens with long-lived secrets in shared environments.

HS256, HS384, and HS512 (HMAC SHA-256/384/512) — the most widely used JWT signing algorithms.