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Overview

Subdomain Login is the quickest way to add authentication to a website. Instead of building and hosting your own login page, you register a DNS CNAME record for a subdomain — like login.example.com — pointing at Subdomain Login. We host the login page, handle authentication, and hand a signed cookie back to your domain.

The idea​

  1. You create a login app in the Admin Portal and choose how your users will identify and authenticate themselves.
  2. You add one DNS CNAME record pointing your login subdomain at the unique subdomain we assign your app (e.g. h5ufc.subdomainlogin.com).
  3. Once the CNAME resolves, Subdomain Login automatically provisions a TLS certificate for your login subdomain via Let's Encrypt — no certificates to manage yourself.
  4. Users who visit your login subdomain are authenticated there, and a signed cookie is written back to your parent domain so your application can recognize them — see Protecting Content.

Why a subdomain?​

Pointing a subdomain at a shared service, rather than embedding a library or SDK, means:

  • No code to integrate to get a working login page — just DNS.
  • Certificates are handled for you — your login subdomain gets its own Let's Encrypt certificate, issued and renewed automatically.
  • One place to configure identification and authentication methods, users, and activity for every app you protect.

What's next​

  • Login Apps — create and configure an app, and connect your domain.
  • Users — add and manage the people who can sign in.
  • Protecting Content — recognize signed-in users in your own app.