OIDC Discovery Viewer
Enter an OpenID Provider's issuer (or full discovery URL), fetch and interpret its /.well-known/openid-configuration and JWKS. Pre-filled with this site's Mock OP for direct testing. Also supports manual JSON paste: when target OP lacks CORS, use curl to fetch discovery (and optional JWKS) then switch to "manual JSON paste" mode to parse.
CORS
"Fetch by URL" requests directly from your browser. If the target lacks cross-origin access (CORS), the browser blocks it — that's normal; use command-line curl instead then switch to "manual JSON paste". This site's Mock OP has CORS enabled.
See Discovery and JWKS explanation in OIDC Core Concepts.