JWT Decoder & Encoder
Decode, verify, and generate JSON Web Tokens locally. Parse header and payload details without server interactions for full privacy.
base64UrlEncode(header) + "." +
base64UrlEncode(payload),
)
Understanding JSON Web Tokens (JWT / RFC 7519)
A JSON Web Token (JWT) is an open industry standard (RFC 7519) for securely transmitting compact, self-contained JSON objects between parties. Because tokens can be digitally signed using either a shared secret (HMAC algorithms like HS256) or a public/private keypair (RSA or ECDSA), receivers can verify the authenticity and integrity of the contained claims.
Header
Specifies the token type (JWT) and the signing algorithm (e.g. HS256, RS256, ES256).
Payload (Claims)
Contains application statements including standard claims: sub (subject), iss (issuer), exp (expiration time), and custom claims.
Signature
Calculated by hashing the Base64Url-encoded header and payload with a secret key to prevent tampering.
Inspect JWTs from the Terminal
To quickly decode a JWT payload in Linux or macOS without third-party CLI tools:
# Decode payload segment using jq and base64 echo "YOUR_JWT_TOKEN" | cut -d'.' -f2 | tr '_-' '/+' | base64 -d 2>/dev/null | jq .
Frequently Asked Questions
Is it safe to decode production JWTs in this tool?+
Yes, 100%. EasyLauncher tools run strictly client-side inside your browser sandbox. Tokens, headers, and secrets are never transmitted across the network, logged, or saved to any database.
Does a JWT encrypt payload data?+
No. Standard JWS (JSON Web Signature) tokens are signed, not encrypted. Anyone with access to the token string can read the payload by Base64Url-decoding it. Never store raw passwords, credit cards, or confidential secrets inside unencrypted JWT claims.
What is the difference between HS256 and RS256?+
HS256 is a symmetric algorithm using a single shared secret for both signing and verification. RS256 is an asymmetric algorithm using a private key to sign the token and a public key to verify it, ideal for microservice architectures and third-party authentication providers.
Need custom enterprise authentication or Zero Trust architecture?
Our security architects design least-privilege OAuth2/OIDC, automated secrets rotation, and SOC 2 Type II compliant identity perimeters.
100% Client-Side Privacy Guarantee
Zero Server LoggingAll computations execute exclusively in your browser sandbox using Web APIs. No code, keys, tokens, or files are ever sent to external servers.
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