Introduction

What LoginWith is and when to reach for it.

LoginWith is SSO infrastructure shaped like HTML. One script tag loads the SDK, one <a href> signs users in. When you need tokens, sessions, and PKCE, the same SDK gives you those without any extra plumbing.

It speaks OAuth 2.0 + PKCE and OIDC on the wire, so every language and framework you already use works. LoginWith owns the identity provider fan-out (Google, GitHub, Microsoft, LinkedIn, GitLab, X, and more soon) — your app just consumes the resulting bearer token.

What LoginWith handles

• PKCE generation, storage, and verification
• JWKS rotation + caching, signature verification
• Provider fan-out — you integrate with one API, get every provider
• Branded login pages at <your-slug>.loginwith.page with no frontend code
• Multi-tenant isolation — one client serving many orgs
• Session bridging across subdomains via signed httpOnly cookies

What LoginWith does not do

• Store your users’ passwords — there are none; every login is delegated
• Host your app or its data
• Replace a customer identity platform for features like MFA policies, fine-grained RBAC, or SCIM provisioning (yet)