Imagine this: your SaaS product has grown quickly, and users are constantly forgetting their passwords. Support tickets pile up, password resets consume engineering time, and the login flow feels more like a barrier than an entry point. Your team decides to modernize by going passwordless, replacing passwords with short codes or magic links. Simple in theory, but the implementation? Not so much.
If you're building with React, here's what you have to tackle: Multiple forms, async calls colliding with redirects, state that doesn’t survive reloads, and code that breaks when users switch devices. Suddenly, what seemed like a straightforward UX improvement feels like a maintenance nightmare.
The real problem isn’t the idea of magic links or OTPs — those are well understood. The problem lies in managing state and security guarantees in a way that keeps your React code clean and your backend trustworthy.
What a passwordless flow actually looks like
At a high level, passwordless authentication follows a simple sequence:
- Collect an email from the user.
- Issue a credential — either a one-time passcode or a magic link.
- Verify the code or token when the user comes back.
- Mark the session as authenticated.
That’s it. No password resets, no strength meters, no secret storage. Just short-lived credentials that expire quickly and can’t be reused.
The tricky part is not the flow itself, but handling all the edge cases:
- 1. Users clicking a link twice.
- 2. Codes expiring while the form is still open.
- 3. Redirects landing in a different tab.
- 4. Sessions being dropped after a page reload.
Without a structured approach, developers end up duct-taping state machines across components and hoping everything holds.
Why security has to be server-first
Even if you nail the React side, passwordless only works if the server enforces the rules. That means:
- Generating cryptographically signed tokens.
- Enforcing expiry windows.
- Preventing replay across devices.
- Making sure resends invalidate old codes.
This isn’t something you want scattered through frontend code. The backend should own these guarantees so the client can stay focused on state and UX.
How Scalekit simplifies it
Scalekit takes on the server-side heavy lifting. It issues and validates short-lived tokens, handles resends safely, and ensures credentials are bound to the right context. You never expose secrets to the client, and you don’t need to reinvent cryptography or expiry logic.
On the React side, you just consume that flow declaratively. Using Scalekit’s SDK, you can:
- Collect an email and request a magic link or OTP.
- Handle redirects automatically and verify tokens.
- Track session state across reloads.
- Show clear UI states for sending, verifying, success, or error.
Instead of juggling timers and redirects by hand, your components stay focused: one handles email input, another handles code entry, and global context keeps track of whether the user is authenticated.
Wrapping up
Passwordless authentication removes one of the biggest sources of friction for users, but only if it’s implemented with both security and developer sanity in mind. By splitting responsibilities — React for state and UX, Scalekit for token security — you get a system that’s secure by default and reusable across projects.
If you’re ready to ditch fragile password resets and move to something users actually enjoy, check out the full guide and working example here: Passwordless authentication in React with Scalekit
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