Please help determining correct authentication strategy

I would like to use Lock for iOS/Swift in my iphone application to allow the user to log in, and then seamlessly authenticate with my React SPA.

Currently I have login setup independently for the iOS and React applications, however some of the pages in the React website are embedded in the iOS app via a webview. I need a way to authenticate with the React website once I log into the iOS app, so that when the user navigates to the webview they aren’t prompted for login.

Is what I am describing SSO? Basically I am confused on which endpoints to call (if any). All of these applications are part of my organization.

Note: The reason the React SPA is necessary is because a small part of the IOS app will embed the website instead of creating the views in native code.
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