Magic Link Authentication Without Token Leakage
Ship passwordless email sign-in with short-lived tokens, secure callback handling, and app-scoped session exchange.
Magic links help conversion, but they are easy to implement in a way that leaks tokens into URLs, logs, or browser history. 1Auth keeps the email flow simple while treating delivery and exchange as a security boundary.
What teams need from this feature
These are the operational constraints that usually turn a simple auth flow into infrastructure work.
- Passwordless sign-in needs low friction without turning every callback into a token exposure risk.
- Replay protection, expiry, and resend behavior become operational work fast.
- The same app portfolio often wants magic links in one product and passwords or OAuth in another.
How 1Auth handles it
1Auth ships the primitive as part of one backend instead of forcing each product to rebuild the same boundary.
Single-use, short-lived flow
Magic-link tokens are short-lived and one-time so the email link behaves like a secure handoff instead of a durable credential.
Exchange-code callback pattern
1Auth finalizes the browser handoff through an exchange step so access tokens do not have to travel in query strings.
Per-app delivery control
Each app can keep its own redirect URLs, email templates, and provider setup while still sharing the core auth backend.
Good fit when
The product gets stronger when the auth model matches the boundary of the app, not the convenience of the provider.
- Signup conversion and low-friction returning login matter more than memorized passwords.
- You need passwordless auth that still fits a serious backend security model.
- You want to combine magic links with OAuth, passkeys, or password fallback inside one auth surface.
FAQ
Questions teams ask before they ship
Should tokens ever live in the callback URL?
Avoid it if you can. The safer pattern is to treat the callback as a short handoff and perform a second step to exchange a code for tokens.
Can magic links coexist with other auth methods?
Yes. 1Auth supports magic links alongside password auth, OAuth, passkeys, email verification, and password reset.
Related Pages
Keep exploring the 1Auth docs cluster
Each page below connects to the same app-scoped auth model from a different buying or implementation angle.
Implement passwordless magic-link auth in FastAPI with secure callback handling, token expiry, and exchange-based session delivery.
Use conversion-friendly auth for AI tools with magic links, OAuth, app-scoped users, and a backend that can support several products over time.
Protect long-lived sessions with single-use refresh tokens, family-based revocation, and short-lived access tokens.