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Hazuu Tools

JWT Decoder

Decode JSON Web Tokens instantly. View header, payload, and signature with syntax highlighting, expiration checks, and claims analysis — all in your browser.

JWT Token
token

Paste a JWT token above and click Decode

or click Sample to try with an example token
info

About JWT Decoder

JSON Web Tokens (JWTs) are an open standard (RFC 7519) used extensively in modern web applications for authentication and information exchange. A JWT consists of three Base64url-encoded parts separated by dots: a header describing the signing algorithm, a payload containing claims (data), and a cryptographic signature. Because JWTs are compact and self-contained, they are the backbone of stateless authentication in APIs, single sign-on systems, and OAuth 2.0 flows.

Our JWT Decoder lets you instantly inspect the contents of any JWT without needing the signing secret. Paste a token and see the decoded header, payload, and signature in a clear, syntax-highlighted view. The tool also validates the token structure, checks expiration status, converts Unix timestamps to human-readable dates, and identifies standard registered claims — all processed entirely in your browser for complete privacy.

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How to Use

01

Paste Your Token

Copy a JWT from your application, API response, or authorization header and paste it into the input field.

02

Click Decode

Hit the "Decode" button to split and Base64url-decode the token into its header, payload, and signature components.

03

Review Results

Inspect the decoded JSON with syntax highlighting, check expiration status, and review standard claims with their descriptions.

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Frequently Asked Questions

What is a JWT Decoder? expand_more
A JWT Decoder is a tool that splits a JSON Web Token into its three components (header, payload, and signature), decodes the Base64url-encoded header and payload into readable JSON, and displays the results. It helps developers inspect token contents, verify claims, and debug authentication issues without needing the signing secret.
Is it safe to decode JWTs in the browser? expand_more
Yes. Decoding a JWT only reveals its contents — it does not validate or forge the signature. This tool processes everything locally in your browser using JavaScript. No data is sent to any server. However, you should never share tokens containing sensitive data in untrusted environments.
Can this tool verify the JWT signature? expand_more
This tool decodes and displays the signature but does not verify it cryptographically. Signature verification requires the secret key (HMAC) or public key (RSA/ECDSA) used by the token issuer, which is not available to a client-side decoder.
What do the standard JWT claims mean? expand_more
Standard claims are registered in the IANA JSON Web Token Claims registry. Common ones include: iss (issuer), sub (subject), aud (audience), exp (expiration time), nbf (not before), iat (issued at), and jti (JWT ID). Each serves a specific role in token validation and authorization logic.