Comment by deltaknight

There is https://openf1.org which has an API, although I don't believe it's real-time. My projects uses the SignalR stream directly from F1, but it's not very API friendly and you have to learn and do a decent amount of processing to make it in to useful display data. Check out the UndercutF1.Data project to see how this is done. FastF1 also has a live timing client, although I don't think its their preferred method of analysis.

After a session is finished, F1 do upload json and jsonStream static files which you can download - checkout the DataImporter class to see how this is done (this is what powers the undercutf1 import` command)