What Is Seamless Auth?

Seamless Auth

Seamless Auth is a passwordless authentication ecosystem. You can run it as a managed hosted service or self-host the whole stack inside your own infrastructure.

It combines a hosted or self-hostable auth server, official SDKs, a CLI for scaffolding a working stack, a developer portal for the managed offering, and an operator dashboard for managing users, sessions, security, and system configuration.

The goal is to give you modern authentication with the same SDKs and session model whether Seamless hosts the auth instance for you or you keep the auth engine and data inside your own stack.

Tip

New here? Start with Managed or Self-Hosted to pick a path, then follow the Managed Quickstart or the Self-Hosted Quickstart.

Note

Seamless Auth is for teams that want passwordless auth with explicit boundaries, inspectable components, and application-owned UX.

Caution

On the self-hosted path, the ecosystem is strongest today for scaffolded full-stack setups and source-visible self-hosting. Deeper existing-project integration and self-hosted deployment automation still need more coverage. The managed path handles hosting for you.

---

Key Characteristics

Exclusively Passwordless

• Authentication is based on cryptographic verification, not shared secrets.
• Supports passkeys, magic links, email/phone OTP, TOTP MFA, and optional OAuth login.

---

Loosely Coupled

• The auth engine runs as its own service inside your stack.
• SDKs are thin integration layers, not hidden platforms.
• Frontend auth flows stay inside your application.
• The admin dashboard is a separate app, not a magical control plane.

---

Server-Side Session Validation

• Sessions are issued and validated using secure, HTTP-only cookies.
• Defense-in-depth approach to authentication.
• Sessions are tracked per device and per browser.

---

Explicit Authorization

• Roles and access control are defined and enforced in your own application code.
• No hidden authorization layers or assumptions.

---

Consistent Environments

• The same core model works locally, in staging, and in production.
• Local development is designed to stay close to deployment reality.
• The CLI can scaffold a production-shaped local stack quickly.

---

The Ecosystem

Seamless Auth is made up of a few focused projects.

Piece	Role
Seamless Auth portal	Managed offering: create apps, pick plans, issue service tokens
seamless-cli	Scaffolds a full local stack for self-hosting
seamless-auth-api	Runs the passwordless auth engine
@seamless-auth/core	Framework-agnostic server auth primitives
@seamless-auth/express	Official Express backend integration
@seamless-auth/react	React auth provider and built-in auth routes
seamless-auth-admin-dashboard	Operator UI for users, sessions, events, security, and config
@seamless-auth/types	Shared domain and API types

If you want the fuller package map, continue to Ecosystem Overview.

---

Core Idea

Seamless Auth treats authentication as infrastructure:

CLI -> Local stack
SDKs -> App integration
Auth API -> Passwordless auth engine
Admin Dashboard -> Operator workflows

---

What You Will Build

By the end of this guide, you will have:

• A working local stack
• Passwordless authentication
• Session management with device-level control
• A clearer mental model of the ecosystem
• Enough context to choose the right package for your next step
• A path to customize auth UI and protect app routes when you leave the starter

---

Next Step

→ Continue to Managed or Self-Hosted