CLIENT-SIDE ONLY
JWT Token Decoder & Debugger
Decode and inspect JSON Web Tokens (JWT) safely. View your JWT header, payload, and signature algorithms securely within your browser without exposing active tokens to external APIs.
Paste your JWT here
Header: Algorithm & Token Type
Header data will appear here...
Payload: Data & Claims
Payload data will appear here...
Verify Signature
HMACSHA256(
base64UrlEncode(header) + "." +
base64UrlEncode(payload),)
base64UrlEncode(header) + "." +
base64UrlEncode(payload),)
Security First Philosophy
- All decoding logic is executed within your browser's V8 engine. No network requests are made during processing.
- We do not store your tokens, secrets, or payloads. All data lives only in your browser's memory.
- Privacy-first analytics that never track sensitive form input or user-identifiable data.
Architectural Isolation
This tool operates in a Sandboxed Environment to prevent XSS and data leakage.