Short answer: open Settings → Privacy & Security → Developer Mode, switch it on and restart. After the restart, unlock the iPhone, tap Turn On and enter your passcode. The switch only shows up once a test build is on the device, and if Stolen Device Protection is on, iOS may make you wait before it lets you change it.
We help teams get test builds onto their testers’ iPhones, and this is the step where testers most often get stuck. Some can’t find the switch. Some worry that “developer” means the phone becomes less secure. Some see a one-hour countdown and give up. All three have simple answers.
When you need Developer Mode
Developer Mode appeared in iOS 16. iOS asks for it when you run an app that was signed for development and testing rather than downloaded from the App Store — for example, a build exported for debugging and installed on registered devices[1]. Apps from the App Store and TestFlight don’t need it.
So if a developer invited you to test their app through a direct link, and iOS shows “Developer Mode required” when you tap the icon, that is expected. Nothing is broken.
How to turn on Developer Mode, step by step
- Install the test build first. Follow the link the developer sent you and install the app. The Developer Mode switch usually appears only after such an app is on the device (or after the iPhone was connected to a Mac running Xcode).
- Open Settings → Privacy & Security and scroll down to the Security section.
- Tap Developer Mode and turn the switch on.
- iOS asks to restart. Tap Restart.
- After the restart, unlock the iPhone. An alert asks whether to turn on Developer Mode — tap Turn On and enter your passcode.
- Open the test app. It launches normally from now on.
The steps are the same on iPad.
“I can’t find Developer Mode on my iPhone”
- No test build installed yet. The switch is hidden until iOS sees a reason to show it. Install the app from the developer’s link first, then look again.
- The app didn’t install. If the icon is grey or the install fails, your device is probably not registered for this build. Send your UDID to the developer — see how to find your iPhone UDID — and ask for a new link after they add it.
- Other install errors. “Unable to Install” or “integrity could not be verified” are a different problem — see how to install an IPA on iPhone.
- Old iOS. Developer Mode exists only on iOS 16 and later. On earlier versions you don’t need it.
- Managed work phone. A company device-management profile can hide or block the setting. Ask your IT team.
Why it can take an hour: Stolen Device Protection
Stolen Device Protection guards your Apple Account and security settings if someone steals your iPhone together with its passcode. When the phone is away from familiar places such as home or work, sensitive changes require Face ID or Touch ID, a one-hour Security Delay, and then Face ID or Touch ID again[2]. Since iOS 26.4 this protection is turned on by default[3].
Apple’s list of delayed actions doesn’t mention Developer Mode by name. Still, several of our testers with Stolen Device Protection on hit a one-hour wait while turning Developer Mode on — usually when they weren’t at home or at the office. If that happens:
- Let the timer run. You don’t need to keep the screen open; iOS notifies you when the delay ends.
- Or do it at home or at work, where iOS usually doesn’t impose the delay.
- Don’t turn Stolen Device Protection off just to skip the wait — that change is delayed too, and the protection is worth keeping.
Is Developer Mode safe?
Yes, for the purpose it was designed for. Developer Mode doesn’t jailbreak the iPhone, doesn’t remove iOS sandboxing and doesn’t give anyone remote access. It allows the device to run apps signed for development and testing, and to connect to developer tools. Apple added the switch precisely so that this ability is off by default and turned on consciously.
The one real rule: install only builds from developers you know and trust — a company you work for, a client, a team whose app you agreed to test. Developer Mode doesn’t make a random IPA from the internet any safer.
For developers: make this step painless
Most tester drop-off happens between “here is the link” and “the app opens”. Send testers one short message with three things: how to send their UDID, the install link, and the Developer Mode steps above — including the note about the one-hour delay. Link this page if it helps.
AppSign keeps builds, registered testers and install links in one place, so testers get something that feels like their own App Store — and every next update installs without repeating these steps.