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JWT Comparator

Compare two JSON Web Tokens side by side. Decode headers and payloads, highlight differences in claims, detect algorithm changes, and check signature matches. Runs entirely in your browser — your data never leaves your machine.

jwt json-web-token compare diff authentication security

Published May 30, 2026

All interactive tools run entirely in your browser. Your data never leaves your device.

How It Works

Paste two JWTs into the left and right panels. The tool decodes both tokens and displays a side-by-side comparison of their headers, payloads, and signatures with color-coded diff status.

Features

  • Side-by-side comparison: view two decoded JWTs simultaneously
  • Field-level diffs: each claim is compared and marked as same, changed, left-only, or right-only
  • Header and payload sections: separate diff tables for headers and payloads
  • Signature match detection: instantly see if signatures are identical
  • 5 examples: pre-loaded JWT pairs for common comparison scenarios
  • Private: runs entirely in the browser — no data transmitted

Use Cases

  • Comparing JWTs before and after token refresh
  • Debugging authentication issues by comparing expected vs actual tokens
  • Verifying algorithm changes (HS256 vs RS256)
  • Checking which claims differ between two tokens