Developer Mode is a switch Apple added in iOS 16. It protects people from installing harmful software by accident, so iOS keeps it off until you need it.
If you open a test app and see Developer Mode Required, this is the setting it means.
Turn it on
- Open Settings, then Privacy & Security.
- Scroll down to Security and tap Developer Mode.
- Turn on the switch. iOS warns that this reduces the security of your iPhone.
- Tap Restart.
- After the restart, unlock the iPhone. When asked to turn on Developer Mode, tap Turn On and enter your passcode.
Open the app again. It should start normally.
Why the switch isn't there
Apple only shows Developer Mode once the iPhone has been paired with a Mac, for example by connecting it to Xcode. Testers without a Mac report that the switch also appears after they try to open an app that needs it. So open the app once, then look again.
Which apps need it
| How the app was installed | Developer Mode |
|---|---|
| App Store | Not needed |
| TestFlight | Not needed |
| Enterprise (in-house) apps | Not needed, according to Apple |
| Run from Xcode, or a development-signed build | Needed |
| An .ipa installed with Apple Configurator | Needed |
| Ad hoc builds | Apple doesn't say. Firebase's documentation says iOS 16 and later can ask for it. |
If you're a developer and want testers to avoid the switch, TestFlight is the route Apple names as unaffected. How the profile types differ.
Turn it off again
Turn off the switch in Settings, Privacy & Security, Developer Mode, and restart. Apps that need Developer Mode won't open until you turn it back on, and you can't run apps from Xcode on the iPhone.
It's a different problem if the app won't install
Developer Mode only matters once an app is installed. If the install itself fails with "Unable to Install" or "integrity could not be verified", the build isn't signed for your iPhone. Fix that error.
Questions
Where is Developer Mode on iPhone?
In Settings, Privacy & Security, under the Security heading near the bottom. It only appears once the iPhone has been paired with a Mac or you have tried to open an app that needs it.
Is it safe to turn on Developer Mode?
Apple says it reduces the security of your device, which is why it asks you to restart and confirm. Turn it on for the apps you trust and turn it off when you finish testing.
Do TestFlight apps need Developer Mode?
No. Apple says Developer Mode doesn't affect apps from the App Store or TestFlight.
Why does my app say Developer Mode Required?
It was signed for testing, not for the App Store. Turn on Developer Mode under Settings, Privacy & Security, restart, and confirm with your passcode.