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Alona Tool – Free Online Tools

JWT Decoder

Popular Runs in Your Browser

Paste a JSON Web Token to read its decoded header and payload, with issued-at and expiry timestamps shown as UTC dates.

Browser-based: this tool works on your device and does not send your input to an Alona Tool server. See the Privacy Policy for details.
Fast Processing

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Example Usage & Test Cases

Inspect a token
Input Scenario:
A token with header {"alg":"HS256","typ":"JWT"} and payload {"sub":"123456","name":"Alona"}
Generated Result:
Pretty-printed header and payload, plus UTC dates for iat/exp claims

How It Works

1

Paste the full token (header.payload.signature) into the box.

2

Read the decoded header and payload shown in the result.

3

Check the UTC dates to see when the token was issued or expires.

Frequently Asked Questions

No. It only decodes the readable parts. Verifying a signature needs the secret or public key and must be done by your server or a trusted library.

Good to Know

Common uses

  • Checking why an API rejects a token (wrong audience or expired)
  • Reading claims while developing login flows

Limitations and notes

  • A decoded payload is not proof the token is genuine; the signature is NOT verified here.
  • Encrypted tokens (JWE) cannot be decoded.

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Free Online JWT Decoder

A JWT is three Base64URL parts separated by dots. This decoder reads the header and payload so you can inspect claims such as subject, issuer and expiry while debugging authentication.

Key Highlights:

  • Free to use, no signup
  • Instant results
  • Processed in your browser
  • Works on mobile and desktop