JWT Compare

Two JWTs often look almost identical — same length, same three-part shape, same base64url gibberish at a glance — while carrying meaningfully different claims underneath. That's common when debugging a refresh flow (did the new token actually get a new exp?), a permissions change (did role really change from viewer to admin?), or a multi-tenant setup (is this really a different token, or the same one reissued?).

This tool decodes both tokens and compares their headers and payloads field by field, the same way the JSON Compare tool diffs two documents — reporting exactly which claims were added, removed, or changed, instead of making you eyeball two walls of base64. Neither token's signature is checked; this is purely a decode-and-diff, entirely in your browser.

• •This compares decoded claims, not signatures — two tokens can have identical claims and completely different (or invalid) signatures. Use the JWT Verifier tool if you need to confirm a signature separately.
• •A changed iat or exp on an otherwise-identical token usually just means it was reissued — that's expected for refresh flows, not necessarily a problem.
• •Watch for claims that disappear entirely (shown as removed) as much as ones that change — a dropped role or scope claim is easy to miss when skimming two long tokens by eye.
• •If the header differs (e.g. a new kid), that often signals the signing key was rotated — worth confirming your verifier is using the right public key or secret going forward.