Download websites that use Auth0

About Auth0

An authentication provider is one of the few technologies that tells you a site has users. A brochure page needs a content system and a contact form. A login screen means accounts, sessions, permissions, password resets and support, plus a decision to buy that machinery instead of writing it. Auth0 sits in the Authentication category as a hosted identity service covering social login, multi-factor prompts, single sign-on and the protocol work behind them.

Detection is where honesty is required. What we can see is the browser-side JavaScript library and the endpoints it calls, so the sites we record are the ones embedding a login widget in their own pages. A large part of this market runs the other way, redirecting a visitor to a hosted login domain, and a redirect leaves nothing on the origin page for a crawler to find. As of September 2026 we detect the library on 565 sites, and the customer base behind the service is certainly wider. Anyone sizing a market from the number should treat it as a lower bound on one integration style rather than a count of accounts.

Version data shows why client-side identity libraries are worth watching. We record 49 distinct release strings across the population, 9.18 among the commonly seen ones. Identity libraries get pinned early in a project, bundled into a build and then left alone, so the spread of releases is wide and old bundles keep running long after the vendor has moved on. For a security researcher the spread is the point. A login library nobody has updated in years is an unwatched dependency, and the sites running one become identifiable as a group instead of one at a time.

Ownership changed what buying the service means. The platform dates from 2013 and now belongs to Okta, so an independent developer tool became part of an enterprise identity portfolio, with the pricing, procurement and bundling that follow. The service is Proprietary, so each detection stands for a contract, and the domains carrying it are working applications with real user bases rather than static pages.

A per-domain lookup answers a narrow question about one site. A list answers the questions that only exist at population scale: how many products in a sector outsource identity instead of building it, which frameworks the integrations sit inside, which bundled releases are stale enough to matter, and how the group shifts between snapshots. Competitors size a market with it. Security teams find exposed builds with it. Integrators find applications already committed to a hosted identity model.