JWT Decoder — Decode & Inspect JSON Web Tokens Online
Decode JSON Web Token headers and payloads with expiration status.
Interactive Tool Workspace
Loading secure in-browser engine for JWT Token Decoder...
Processing Limits & Device Capabilities
Processed client-side in browser memory. Recommended maximum file size is 50 MB on desktop and 15 MB on mobile.
How to Use JWT Token Decoder
- Paste an encoded JSON Web Token (JWT) into the input box.
- Instantly inspect the decoded Header (algorithm, type) and Payload claims.
- Check calculated token validity and expiration timestamp against current time.
About JWT Token Decoder
The JWT Token Decoder parses dot-separated JSON Web Tokens, decodes the Base64Url header and payload claims, and calculates expiration status in real time. Please note: This is a client-side debugging tool; it does not verify cryptographic signatures.
Frequently Asked Questions
Does this tool verify the JWT signature?
No. Cryptographic signature verification requires your application secret key or public certificate. This tool operates strictly as a client-side inspector for debugging and viewing token claims without signature validation.
Are my private auth tokens secure when using this tool?
Yes. All parsing and Base64Url decoding execute entirely within your local browser memory. Tokens are never transmitted to any external server or API.
What are the three parts of a JSON Web Token?
A standard JWT consists of three dot-separated Base64Url-encoded parts: the Header (signing algorithm and token type), the Payload (identity and authorization claims), and the Signature.
How does the tool calculate token expiration?
The tool reads the exp (expiration time) claim in seconds since Unix epoch, converts it to standard UTC and local dates, and compares it to your system clock to report whether the token is active or expired.
Can I decode encrypted JWTs (JWE)?
No. Encrypted tokens (JWE) have five dot-separated parts and encrypted ciphertext payloads that require the decryption key. This tool inspects signed JSON Web Tokens (JWS).