SWR & caching

On first load, many websites must make a network request to determine whether a User is logged in before the site can start rendering the user interface. This slows down users' ability to interact with the application and ultimately leaves them with a sluggish experience.

Stytch JavaScript SDK embraces stale-while-revalidate (SWR) - a caching and data fetching strategy that promises faster time-to-interactivity and snappier UX. While SWR is most closely associated with React, the principles can apply to any web application.

Here's how it works:

• The page first loads. Stytch's SDK checks cached data to determine if a User has logged in previously on the same device, and returns that data to your app immediately.
• Stytch's SDK refreshes the User's data in the background while your app starts.

• Your app makes requests to your backend to pull in application-specific data. Your backend validates the session stored in the request's cookies, and then completes the request.

• In the rare case that the User's session has been terminated from another device, your backend will fail the request and return a 401 error. The Stytch SDK will also notify your app that the session is no longer valid through the useStytchUser and useStytchSession hooks or HOCs.

If a SWR approach isn't right for you, you can explicitly call stytch.user.get() to refresh the User object with a network call, and/or stytch.session.authenticate() to make sure the User is still logged in.