FlexyPin is a connector pin designed to be used with castellated modules with pitch down to 1.27mm. You might be able to use it with 1.00mm pitch but that would require a more expensive PCB because the footprint drills would be very close.
It allows for easy insertion and removal of modules without the need for soldering.
It works great for flashing/testing jigs and other use-cases where castellated modules are involved.
FlexyPins are gold-plated and keep their shape well. We haven’t seen any issues over multiple (1000+) insert-remove cycles.