JWT Decoder & Inspector
Decode, inspect, and analyze JSON Web Token headers and payloads instantly.
📖 How to Use This Tool
Follow these quick steps to decode authentication tokens:
- Step 1: Paste your encoded JSON Web Token into the input area.
- Step 2: View the decoded header and payload claims split cleanly into formatted JSON.
- Step 3: Inspect expiration timestamps, subject IDs, and authorization roles securely.
✨ Key Benefits
This utility runs entirely inside your web browser. No sensitive session tokens or authorization headers are ever transmitted to remote servers, guaranteeing total data privacy.
🔗 Related Articles & Blog Posts
- Understanding JSON Web Tokens (JWT) and Session Security
- Why Client-Side File Processing Keeps Your Data Safe
How JSON Web Token (JWT) Decoding Works
Decode, inspect, and verify JWT headers, claims, expiration timestamps, and signature algorithms.
Calculation & Methodology
JWT = Base64Url(Header) + "." + Base64Url(Payload) + "." + Signature
Format & Validate JSON Payloads
Format raw payload claims and test JSON structure with our validator.
Format JSONFrequently Asked Questions
Does decoding a JWT expose private signing keys?
No, JWT headers and payloads are merely Base64-encoded strings and can be decoded by anyone; signatures require private keys.
What do the `exp` and `iat` claims represent in a JWT?
`iat` indicates the Unix timestamp when the token was issued, and `exp` defines when it expires.