Short answer: go to Settings → Privacy & Security → Developer Mode, turn it on, tap Restart, then after the phone boots swipe up, tap Enable and enter the passcode. If the switch isn't there, pair the phone with a Mac and start installing a development app from Xcode first — Apple says the option only appears after pairing has started or the device was previously paired to a Mac.
What Developer Mode is
Developer Mode is Apple's gate for running development-signed apps — anything you build and install from Xcode rather than from the App Store or TestFlight. Apple says it "protects people from inadvertently installing potentially harmful software" and doesn't affect normal App Store installs (Apple Developer, checked 17 September 2026).
An automation runner on a phone farm is a development-signed app, so every farm iPhone needs Developer Mode on.
Step by step
From Apple's documentation:
| Step | On the iPhone |
|---|---|
| 1 | Open Settings → Privacy & Security |
| 2 | Under Security, turn on Developer Mode |
| 3 | An alert warns that it reduces security. Tap Restart |
| 4 | After the restart, an alert asks you to confirm |
| 5 | Swipe up, tap Enable, enter the passcode |
To turn it off later, switch it off in the same place and restart. Apple notes that you can't run apps from Xcode on the device until you turn it on again.
Gotchas
The switch is missing. Apple's note: "Developer Mode only appears in Settings if you initiate pairing or if you previously paired the device to a Mac." Connect the phone to the Mac with a data cable, tap Trust, and start the install from Xcode. The option appears afterwards.
It needs the passcode. A phone with no passcode, or one you don't know, can't finish step 5. Set a passcode you record in your inventory sheet.
It restarts the phone. Do it before you sign in to accounts and before the phone joins a run, not in the middle of one.
It survives normal restarts. You don't need to redo it after a reboot. If it turns off after a restore or reset, repeat the steps.
The app still won't open. Developer Mode is one of two gates. The other is trusting the developer profile: Settings → General → VPN & Device Management → your profile → Trust. Skipping it produces a silent failure — see Install the runner.
Checklist for each farm phone
| Check | Done when |
|---|---|
| Data cable, phone trusted on the Mac | Phone appears in Xcode |
| Runner installed from Xcode | Install finished without errors |
| Developer Mode on | Switch shows on after restart |
| Developer profile trusted | Profile shows as trusted |
| Auto-Lock set to Never | Screen stays on |
| Signing valid | Re-sign date noted if on a free account — see 7-day signing |
Doing this with Farmero
Farmero's Connect an iPhone guide walks through the same order: cable and trust, runner install, then Developer Mode, which appears after the first install. The whole per-phone flow is in the Mac setup guide. If a phone keeps dropping off after setup, see iPhone keeps disconnecting.
FAQ
Why can't I find Developer Mode on my iPhone?
Apple says it only appears once you start pairing the phone with a Mac or have paired it before. Connect it, trust the Mac, and start an install from Xcode.
Is Developer Mode dangerous?
Apple warns that it reduces the device's security, which is why it asks you to confirm twice. Use it on phones dedicated to the farm, not your personal phone.
Do I need Developer Mode for App Store apps?
No. Apple says it doesn't affect normal installs from the App Store or TestFlight. It is only for development-signed apps.
Does Developer Mode turn off by itself?
It stays on through normal restarts. Turn it off in Settings, or redo the steps if the phone has been restored.