JWK Viewer
JWTParse a JSON Web Key Set (JWKS) or a single JWK and view each key's type, use, algorithm, key ID, and size in a readable table
jwkjwksjwtoauthoidckeys
How to use JWK Viewer
- 1.Paste a JWKS document (the JSON your OAuth/OIDC provider serves at /.well-known/jwks.json) to see every key's type, use, algorithm, and key ID at a glance.
- 2.Paste a single bare JWK object (not wrapped in a "keys" array) and it's detected automatically.
- 3.Check the duplicate-kid warning when debugging a "no matching key" JWT verification error: a repeated key ID across entries is a common root cause.
Frequently asked questions
Does this verify or use the keys to check a signature?
No, it only inspects and summarizes the key fields. Use JWT Decode / Verify if you need to actually validate a token against a key.
What's the difference between a JWK and a JWKS?
A JWK is a single JSON Web Key object; a JWKS (JSON Web Key Set) is the { "keys": [...] } wrapper most identity providers publish so clients can look up the right key by kid.
How is key size calculated?
For RSA and oct keys it's estimated from the base64url-encoded modulus/key length; for EC and OKP keys the curve name (e.g. P-256) is shown instead of a bit size, since curve strength isn't a single byte length.
Is my key data sent anywhere?
In the browser tool, no: parsing happens entirely client-side. Avoid pasting private key material (JWKS endpoints normally only publish public keys, so this is rarely a concern in practice).
Use via API, SDK, or MCP
cURLcurl https://api.utilix.tech/v1/tools/jwk-viewer \
-H "Authorization: Bearer utx_live_..."
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