EErgoKit

Developer / Security

JWT Decoder

Decode JWT headers and payloads locally without sending tokens to a server.

Browser-onlyLocal inputNo upload
Local runner

Decode JWT locally

JWTs are decoded locally in your browser. Tokens are not sent to ErgoKit Workers.

Paste a JWT to inspect its header, payload, signature, and common time-based claims.

Checks

  • JWT segment structure
  • Base64URL decoding
  • Header and payload JSON parsing
  • exp, iat, and nbf claim timing

Result

  • Decoded header
  • Decoded payload
  • Signature segment
  • Expiry and validity warnings

Guardrails

  • Runs fully in your browser
  • Token is not sent to a server
  • Signature is displayed but not verified
  • Copy decoded JSON safely

Privacy

This tool processes input locally in your browser. Input is not sent to ErgoKit Workers or stored.