KivTools

JWT Inspector & HMAC Verifier LOCAL ONLY

Decode a JSON Web Token, inspect its standard claims, and verify an HS256, HS384, or HS512 signature locally.

Token
Claim checks
Algorithm—
Expiration—
Not before—
Issuer—
Decoded header
Inspect a token to view its header.
Decoded payload
Inspect a token to view its payload.
Verify an HMAC signature

The secret is used only by your browser's cryptography API. This verifier supports HS256, HS384, and HS512; it does not send the token or secret to KivTools.

Inspect a signed JWT, then enter the corresponding HMAC secret to verify it.

JWT inspection is not authentication

Decoded claims are readable Base64URL data, not proof that a token is trusted. Check its algorithm, expiry, intended issuer and audience, then verify its signature with a trusted key or secret before accepting it in an application.

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