Useful JWT Tools starting points

Jump into a common task, then use the full directory below for more specialized tools.

JWT HS256 Generator JWK Thumbprint Calculator JWT Decoder JWT Header Decoder JWT Payload Decoder JWT Claims Inspector

14 browser developer tools

JWT & JWK Tools

Decode and verify token structures locally while keeping signatures, claims, key trust and authorization as separate checks.

Choose the developer job first

Start with the task you need—formatting, validation, conversion, inspection, or cryptographic checks—and switch tools only when the format or rule changes.

Decode before you trust

Inspect compact token header/payload/claims and time fields without calling readable data verified.

JWT DecoderThe token is decoded as you type. Trust status is visually separated from readable claims so “decoded” is never presented as “verified”.JWT Header DecoderInspect alg, typ, kid, and other header parameters without uploading the token or treating unverified data as trusted.JWT Payload DecoderInspect payload claims in your browser without verifying or trusting the token signature.JWT Claims InspectorReview token claims without confusing readable payload data with a verified or authorized token.JWT Expiration CheckerSee whether a decoded token is expired or not yet active without claiming the token is authentic.JWT Base64URL Parts InspectorShow encoded lengths, decoded header/payload text, and signature byte length without verifying trust.

Verify signatures

Use an explicit shared secret for HS256 or an explicit SPKI public key for RS256.

JWT HS256 VerifierCheck an HMAC signature in the browser; a valid signature alone does not establish issuer, audience, expiry policy, or authorization.JWT RS256 VerifierCheck alg=RS256 with Web Crypto while keeping issuer/audience/key-discovery/application-policy validation separate.

Generate test tokens

Create local HMAC or RSA test tokens with explicit key material and algorithm boundaries.

JWT HS256 GeneratorGenerate a compact HS256 JWS/JWT with Web Crypto using a secret that never leaves the browser.JWT RS256 GeneratorSign test JWTs in your browser without uploading the private key and keep production key-handling responsibility explicit.JWT Claim Time ConverterWork with exp, iat, and nbf timestamp values locally using Unix-epoch seconds.

Inspect keys

Review one JWK, a JWKS inventory, or calculate an RFC 7638 thumbprint.

JWK InspectorReview kty, kid, use, alg, required members, and whether private-key material appears in the pasted JWK.JWKS InspectorReview keys[] structure, kty/alg/use/crv fields, and accidental private material in a pasted JSON Web Key Set.JWK Thumbprint CalculatorCanonicalize the required members for RSA, EC, OKP, or oct JWKs and return the Base64URL SHA-256 thumbprint.

All JWT & JWK Tools

JWT Tools

JWT Decoder

Paste a JWT to decode its header and claims locally, then see algorithm, expiry/activity state, signature metadata, and registered claims without confusing decoding with verification.

JWT Tools

JWT Header Decoder

Decode and pretty-print the protected header of a compact JWT locally.

JWT Tools

JWT Payload Decoder

Decode and pretty-print the JSON claim payload of a compact JWT locally.

JWT Tools

JWT Claims Inspector

Inspect JWT registered/custom claims locally with exp/nbf/iat status, ISO timestamps, claim counts, and clear verification boundaries.

JWT Tools

JWT Expiration Checker

Check exp, nbf, and iat NumericDate claims against the current browser time.

JWT Tools

JWT HS256 Generator

Create an HMAC-SHA-256 signed JWT locally from JSON header and payload objects.

JWT Tools

JWT HS256 Verifier

Verify an HS256 JWT locally with a shared secret while separately showing decoded claims and algorithm/claim-validation boundaries.

JWT Tools

JWT Claim Time Converter

Convert JWT NumericDate seconds to ISO/UTC time and ISO timestamps back to NumericDate seconds.

JWT Tools

JWT Base64URL Parts Inspector

Inspect the three Base64URL segments of a compact signed JWT/JWS.

JWT Tools

JWK Inspector

Inspect a JSON Web Key locally and check the required members for common key types.

JWT Tools

JWK Thumbprint Calculator

Calculate an RFC 7638 SHA-256 JWK thumbprint locally.

JWT Tools

JWT RS256 Verifier

Verify RS256 JWT signatures locally using an SPKI PUBLIC KEY PEM with decoded claim status and a generated browser-only demo workflow.

JWT Tools

JWT RS256 Generator

Generate RS256 JWTs locally from JSON header/payload and a PKCS#8 PRIVATE KEY PEM, with an optional ephemeral demo key pair.

JWT Tools

JWKS Inspector

Inspect JWKS key metadata locally, filter by kid, find duplicate key IDs, and flag private-key members without fetching or trusting an issuer.