JWT Decoder

Online tool for viewing JWT header and payload without verifying the signature.

Обработка выполняется локально в браузере. Данные не отправляются на сервер.

For this tool, processing runs locally in your browser and data is not sent to the server.

JWT Decoder is a free online tool for viewing JSON Web Token contents in readable form. It decodes header and payload from base64url and shows main claims. Processing runs locally in your browser and data is not sent to the server.

What it does

Output

Processing

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How to use

Paste a JWT token in header.payload.signature format.
Click Decode to view header and payload as readable JSON.
Review claims: alg, typ, iss, sub, aud, iat, exp, nbf, and other fields.
Keep in mind that the signature is not verified: decoding does not confirm trust in the token.

More about this tool

JWT Decoder shows JSON Web Token contents in readable form. The tool decodes header and payload from base64url, formats JSON, shows the signature as a separate part, and displays main claims: alg, typ, kid, iss, sub, aud, iat, exp, nbf, and jti.

It is useful for debugging APIs, authorization, OAuth/OpenID Connect, webhooks, and backend integrations. JWT signature is not verified, so the service cannot be used to confirm trust in a token.

Processing runs locally in your browser.

Decodes JWT header and payload
Shows JSON in readable form
Shows main claims
Shows exp, iat, and nbf as date and time
Helps debug APIs, OAuth, and authorization
Runs in the browser
Data is not sent to the server
No registration required

Frequently Asked Questions

What does the JWT decoder do?

It decodes JWT header and payload from base64url and shows them as readable JSON. The signature is shown separately but not verified.

Does the tool verify the JWT signature?

No. This service only decodes JWT. It does not verify the signature or confirm that the token is trusted.

Can I use the decoder to check token security?

No. Decoding shows token contents but does not prove authenticity. Verification requires a separate signature check with a secret or public key.

What is the JWT header?

The header contains service data such as algorithm alg, type typ, and sometimes key id kid.

What is the JWT payload?

The payload contains claims — token data such as iss, sub, aud, iat, exp, nbf, and custom fields. Payload is usually not encrypted and can be read by anyone with the token.

What does exp mean in JWT?

exp is the Unix timestamp of token expiration. The decoder can show it as a regular date and hint whether the token has expired.

Is it safe to paste a JWT into an online decoder?

The tool should run locally in the browser and not send data to the server. Still, do not paste production access tokens, refresh tokens, secrets, or personal data.

Why is JWT payload visible without a password?

JWT is usually signed, not encrypted. Base64url is encoding, not protection. Payload can be read without a key.

Is my data sent to the server?

No. Processing runs locally in your browser and data is not sent to the server.

Do I need to register?

No. The tool works without registration.

More about this tool

It is useful for debugging APIs, authorization, OAuth/OpenID Connect, webhooks, and backend integrations. JWT signature is not verified, so the service cannot be used to confirm trust in a token.

Processing runs locally in your browser.

Decodes JWT header and payload
Shows JSON in readable form
Shows main claims
Shows exp, iat, and nbf as date and time
Helps debug APIs, OAuth, and authorization
Runs in the browser
Data is not sent to the server
No registration required

Frequently Asked Questions

What does the JWT decoder do?

It decodes JWT header and payload from base64url and shows them as readable JSON. The signature is shown separately but not verified.

Does the tool verify the JWT signature?

No. This service only decodes JWT. It does not verify the signature or confirm that the token is trusted.

Can I use the decoder to check token security?

No. Decoding shows token contents but does not prove authenticity. Verification requires a separate signature check with a secret or public key.

What is the JWT header?

The header contains service data such as algorithm alg, type typ, and sometimes key id kid.

What is the JWT payload?

The payload contains claims — token data such as iss, sub, aud, iat, exp, nbf, and custom fields. Payload is usually not encrypted and can be read by anyone with the token.

What does exp mean in JWT?

exp is the Unix timestamp of token expiration. The decoder can show it as a regular date and hint whether the token has expired.

Is it safe to paste a JWT into an online decoder?

The tool should run locally in the browser and not send data to the server. Still, do not paste production access tokens, refresh tokens, secrets, or personal data.

Why is JWT payload visible without a password?

JWT is usually signed, not encrypted. Base64url is encoding, not protection. Payload can be read without a key.

Is my data sent to the server?

No. Processing runs locally in your browser and data is not sent to the server.

Do I need to register?

No. The tool works without registration.