Stable Numbers
JWT Debugger
Decode and inspect JSON Web Tokens. Understand JWT structure, validate format, and explore claims without exposing secret keys.
JWT Input
Validation Status
✓
✗
Valid JWT Structure (header.payload.signature)
✓
✗
Valid Header (Base64 JSON)
✓
✗
Valid Payload (Base64 JSON)
✓
!
(expires: )
ⓘ
Signature verification requires secret key (not implemented for security)
Header
Payload
Signature
Algorithm:
Claims Analysis
Standard Claims
No standard claims found
Custom Claims
No custom claims found
Token Timeline
Issued:
Expires:
JWT Builder (Educational)
⚠️ For testing only - not cryptographically signedUnderstanding JWTs
Structure: JWTs consist of three Base64URL-encoded parts separated by dots: header.payload.signature
Header: Contains metadata about the token, typically the signing algorithm (alg) and token type (typ)
Payload: Contains claims - statements about an entity and additional data
Signature: Ensures the token hasn't been tampered with (requires secret key to verify)
Security Note: Never paste tokens containing sensitive data into online tools. This tool runs entirely in your browser.