BunchTool — JWT Token Generator & Decoder
Presets:
⚙️ Header, Payload & Signature Secret
+Exp:
🎫 Encoded JSON Web Token String
Status: Valid HS256 JWT Token
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JWT Token Generator & Decoder —
Create & Verify JSON Web Tokens Online

Our free JWT Token Generator & Decoder provides an interactive security solution to construct, sign, decode, and verify JSON Web Tokens (RFC 7519) directly inside your web browser. Supports standard HMAC signature algorithms (HS256, HS384, HS512), Base64URL string encoding, and custom secret keys. Easily add standard payload claims including Subject (sub), Issuer (iss), Audience (aud), Issued At (iat), and Expiration (exp) timestamps. Need to inspect existing token payloads? Use the Decode & Verify JWT mode to extract Header & Payload JSON objects and verify token expiration. All encoding and signature math runs 100% client-side in secure local JavaScript—meaning your secret keys and auth tokens are never uploaded to remote servers.

Dual Modes: Encode & Sign JWTs or Decode & Verify existing token strings
Supports HS256, HS384, HS512 HMAC algorithms and Base64URL string formatting
Expiration claim helper buttons (+1 Hr, +1 Day, +7 Days) with live validity badge
Sample JWT presets (User Auth, API Access, OAuth Refresh) and exportable token.jwt
🎫
Base64URLEncoding Engine
HS256 HMACToken Signatures
100% PrivateBrowser Computed
How It Works

Generate JSON Web Tokens in three steps

Step 1
⚙️
Configure Header & Claims

Edit the JSON payload claims or click a preset (User Auth, API Access, OAuth Refresh).

Step 2
🔑
Set Secret Key & Expiration

Enter your signature secret key, select algorithm (HS256), and set expiration claims (+1 hr, +1 day).

Step 3
📋
Copy or Download JWT

Inspect the compiled JWT string, copy the output, or download token.jwt.

Why BunchTool

Why use our free JWT Token Generator & Decoder?

🎫
RFC 7519 Compliant Token Builder

Generates standard Header.Payload.Signature JWT structures with Base64URL encoding and HMAC signature calculation.

🔍
Integrated Token Decoder & Verifier

Decode arbitrary JWT token strings to inspect header metadata, claims, and verify whether a token is active or expired.

🔒
100% Private In-Browser Cryptography

All Base64URL encoding, payload formatting, and signature math execute locally in your browser. Secret keys and tokens are never uploaded to any server.

FAQ

Frequently asked questions

What is a JWT (JSON Web Token) and how is it structured?
A JWT is an open standard (RFC 7519) for transmitting secure claims between parties. A token consists of three Base64URL-encoded parts separated by dots: Header.Payload.Signature.
How does the Jwt Generator process inputs locally inside browser memory?
Base64URL converts JSON byte sequences into URL-safe ASCII strings by substituting '+' with '-' and '/' with '_', while stripping trailing '=' padding characters.
What are standard claims like sub, iss, aud, and exp in a JWT payload?
'sub' identifies the Subject (user ID), 'iss' is the Token Issuer, 'aud' specifies the Audience, and 'exp' is the expiration timestamp after which the token is invalid.
Can I decode and verify existing JWT tokens with secret keys?
Yes. Code parsing, minification, and syntax formatting for the Jwt Generator run entirely inside your local browser engine. No source code or markup is transmitted to remote servers.
Is my secret key or payload data uploaded to external servers?
No. All Base64URL encoding, JSON parsing, signature math, and token generation execute 100% locally inside your browser.
Detailed Guide

Understanding RFC 7519 JSON Web Tokens, Base64URL Encoding & HMAC Signatures

A JSON Web Token (JWT) is an RFC 7519 open standard for securely transmitting JSON claims between stateless web applications and microservices via an encoded string.

A JWT string comprises 3 dot-separated Base64URL segments: Header.Payload.Signature. Base64URL encoding replaces + with - and / with _ while omitting trailing padding characters (=) for URL safety.

The HMAC SHA-256 (HS256) signature guarantees token authenticity and tampering protection. Standard claims like exp (Expiration Time) and iat (Issued At) protect against replay attacks.

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