Clerk
Clerk is a hosted authentication and user management service with prebuilt UI components and SDKs for React, Next.js, Expo, Astro and similar frameworks.
Tiered plans (free through enterprise) priced on monthly retained users, with separate per-connection charges for enterprise SSO and paid add-ons for B2B organizations and machine authentication.
Proprietary
Appears in 1 guide
Where it ranks
Guides that include Clerk.
Security headers
What Clerk's website sends to your browser.
Scanned 2026-08-25. Grade headers C, scoring 55 out of 100.
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No Content-Security-Policy, so no defence in depth against cross-site scripting
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Strict-Transport-Security is set
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X-Content-Type-Options: nosniff is set
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X-Frame-Options is set
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Referrer-Policy is set
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No Permissions-Policy, so powerful browser features are not restricted
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No Cross-Origin-Opener-Policy
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No Cross-Origin-Resource-Policy
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No server-version or X-Powered-By disclosure
This is one narrow, automated check of the HTTP response headers on the vendor's own website. It says nothing about how the product itself is built, how it stores your data, or whether it has ever been audited. A good grade here is a small signal that somebody was paying attention.