JWT Decoder Online (Inspect Header, Payload & Expiration)
Inspect JSON Web Token headers and payload claims with human-readable expiration dates. Client-side only; does not verify signatures without secrets.
Debug authentication workflows and inspect JSON Web Tokens (JWT) without risking credential leaks. Decodes the header and payload claims into formatted JSON, converts Unix timestamps into human-readable dates, and flags token expiration status.
How to Use JWT Decoder Online (Inspect Header, Payload & Expiration)
Select Your File
Drag and drop your file or click Browse to select from your device.
Set Target Options
Choose desired format, compression level, or customization parameters.
Convert & Download
Click Convert to process instantly in local memory and save your result.
Frequently Asked Questions
Is it safe to paste live production JWTs into this tool?
Yes! Unlike cloud-based JWT debuggers that send your token across the web, this decoder runs 100% locally in your browser. Your sensitive auth tokens, user IDs, and permissions never leave your machine.
How does the tool show token expiration?
The tool extracts the standard "exp" (expiration) and "iat" (issued at) claims, compares them against your local clock, and displays whether the token is currently active or expired.
Can this tool verify the cryptographic HMAC or RSA signature?
You can inspect the signature bytes and algorithm type (HS256, RS256, ES256). For security reasons, signature verification with private keys should always be performed within your secure backend application.
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