PitlaneXcode replacement for indie developers

Make the iOS simulator use less memory

A fresh simulator boots about 170 background services before your app starts. Pitlane switches off the ones your app never calls.

Download for macOS (v1.1.1)

Pitlane building a project: the project list on the left, the build log on the right, and a menu to resolve packages and clear caches

23 GB became 5.8 GB

Measured on a fresh iOS 26.5 simulator, right after boot: 217 processes and 23 GB became 67 processes and 5.8 GB. On another boot, 183 processes and 19 GB became 76 and 7.9 GB. Between a half and a quarter survives, depending on the run.

Stock23 GB

With Pitlane5.8 GB

One iOS 26.5 simulator on one boot. 217 processes became 67.

Where the memory goes

A simulator is a whole iPhone's worth of services running on your Mac: Siri, Spotlight, News, photo analysis, iCloud sync, Screen Time. They start with every boot, whether or not your app ever calls them. Boot three simulators and you pay for all of it three times.

What Pitlane switches off

Reduce Simulator Memory sits in the menu next to the simulator picker. It disables those services inside that one simulator and restarts it. The change is saved in the simulator, so it sticks across reboots.

Your Mac's own services are never touched. Only a fixed list of services is eligible, and the core that draws the Home Screen and runs your app is left alone.

What stays on

Anything your app declares. After each run Pitlane reads the project's entitlements, the built Info.plist and its app extensions, and keeps the services they imply: push notifications, universal links, widgets and Live Activities, HealthKit, HomeKit, iCloud, photos, contacts, calendars and Siri.

StoreKit leaves no trace in those files, so the App Store services are kept by default. Settings holds the keep-list.

See what fits

The sidebar lists every booted simulator with its process count and its real memory footprint, the figure Activity Monitor shows, plus the total against your Mac's RAM. It refreshes every ten seconds.

Before every run

Switch on Reduce simulator memory before Build & Run and new simulators start light. The first run of a project costs one extra simulator restart. Later runs cost nothing.

Putting it back

Restore Background Services returns a simulator to stock, and so does erasing it. The reduction needs an iOS 18 or newer runtime.

Questions

How do I make the iOS simulator use less memory?

Switch off the background services your app never calls. Reduce Simulator Memory in Pitlane does it for one simulator at a time: Siri, Spotlight, News, photo analysis and iCloud sync stop, and the simulator ends up two to four times smaller in memory.

Will my push notifications, widgets or HealthKit code still work?

Yes. Pitlane reads the project's entitlements, the built Info.plist and its app extensions after each run, and keeps the services they imply, from push to widgets to HealthKit.

Can I run four or five simulators on an 8 GB or 16 GB Mac?

That is what the reduction is for. Reduced simulators fit several at once, and the sidebar shows each one's footprint and the total against your RAM, so you can see what fits.

Does it work on older iOS runtimes?

It needs an iOS 18 or newer runtime. Older runtimes accept the change and forget it on reboot.

How do I undo it?

Restore Background Services puts a simulator back to stock. Erasing the simulator does the same.

Pitlane