I needed to test an app on the iOS simulator that used a local API provided by Laravel over Valet. I’d enabled ssl for the domain with the valet secure command but was receiving the following error in the Xcode console.

File Transfer Error: The certificate for this server is invalid. You might be connecting to a server that is pretending to be which could put your confidential information at risk.

I had a real nightmare Googling a good solution, but finally came across exactly what I was looking from Juan Rangel on StackOverflow. https://stackoverflow.com/a/55098328/426171

In the end, all that I needed to do was drag the following file and drop it on the emulator.

~/.config/valet/CA/LaravelValetCASelfSigned.pem

The option in the picture below was automatically enabled when I dropped the file. If you want to check, you can find it at Settings > General > About > Certificate Trust Settings (at the very bottom of the About screen).