JWT Debugger - Encode & Decode Locally

Create signed JWTs with HS256/HS384/HS512 or decode tokens side by side. All cryptography runs in your browser; nothing is sent to a server.

🔒 Processed Locally

Encode & sign

Required for HS256, HS384, and HS512. Ignored for none.

Decode

0 characters

Paste a token or generate one on the left. JWTs often start with "eyJ…"

How to use JWT Debugger

  1. 1Choose a signing algorithm (HS256/HS384/HS512) or none for an unsigned token
  2. 2Edit header and payload JSON, enter a secret for HMAC, then click Generate JWT
  3. 3The signed token appears on the left and is copied into the decoder column
  4. 4Or paste any JWT on the right to inspect header, payload, and signature segments
  5. 5Use Auto-paste from clipboard or Copy on any panel as needed

Privacy Guarantee

This tool runs entirely in your browser. Secrets and tokens are never uploaded or logged.

🔒 Processed locally in your browser.