JWT Validator
Verify a JWT token's HMAC signature and check its expiry online, instantly. Free JWT validator for HS256, HS384, and HS512 signed tokens.
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Frequently asked questions
What is JWT Validator?+
Verify a JWT token's HMAC signature and check expiry — entirely in your browser.
How do I use JWT Validator?+
Validates HS256, HS384, and HS512 signed tokens. Enter the secret key to verify the signature cryptographically. Shows expiry status (valid / expired) and decoded claims. Note: only HMAC (shared secret) tokens can be verified — RS256/ES256 require a public key
Is JWT Validator free?+
Yes, JWT Validator is completely free. No account or sign-up required, and all processing happens in your browser — nothing is sent to a server.
Is my data safe when I use JWT Validator?+
Yes. JWT Validator runs entirely in your browser using JavaScript and Web APIs — your input is never uploaded, transmitted, or stored on any server.