SuperTokens is an open source authentication solution offering features like: Different types of login: Email / password, Passwordless (OTP or Magic link based).

SuperTokens.com

How do we use supertokens with our own UI when also using SSR?

Have a look at the NextJS guide > session verification > with ssr

Even if you have not using NextJS, it’s similar

https://supertokens.com/docs/thirdpartyemailpassword/nextjs/session-verification/in-ssr

It will only work if the apiDomain === websiteDomain

So the backend needs to get the session and send prop data to the frontend?

Well you can do whatever you like with the session info on the server side

```
exports.validateAndNormaliseInputOrThrowError = validateAndNormaliseInputOrThrowError;
function getWindowOrThrow() {
    if (typeof window === "undefined") {
        throw Error(
            "If you are using this package with server-side rendering, please make sure that you are checking if the window object is defined."
        );
    }
    return window;
}
```

So maybe I actually need to use the framework to not execute a supertokens frontend function unless its executing on the frontend?

Yes. That would be a solution. You can do that via the dynamic HOC provided by NextJS

https://supertokens.com/docs/thirdpartyemailpassword/nextjs/protecting-route

I'm using Nuxt, which I'm realizing was a bad choice

Hehe. Well.. they must have some equivalent

So in your NextJS example, the server is getting the session and passing props to a component

Does the component use the props and get rendered on the server side?

ahh ok so that would also potentially work for me