How to turn on Developer Mode on iPhone: 4 steps (2026)

By Sigsten Gustavii· 27 October 2026· 8 min read

Since iOS 16, an iPhone will not open an app you installed yourself, outside the App Store and TestFlight, until you turn on a setting called Developer Mode. The name makes it sound like something only programmers need. In practice, anyone who wants to run their own app on their own phone meets it, usually on the day they try.

This guide shows where the switch is, what each prompt means, when you need it and when you do not, and how to turn it off again. It is written for people making apps with Borel, but the steps are Apple's and the same for anyone.

What Developer Mode is

Developer Mode is a privacy and security setting in iOS. With it off, which is how every iPhone comes, the phone only runs apps from the App Store, from TestFlight and from a company's own managed distribution. With it on, the phone also runs apps signed for development: apps that a developer, or a tool working for you, signed and installed directly.

Apple keeps it off by default so that nobody can be talked into installing unknown software without noticing. Turning it on takes a restart and your passcode, which is the point: it is a deliberate choice you make on the phone itself.

How to turn on Developer Mode, step by step

You need an iPhone on iOS 16 or later and its passcode. It takes about a minute, most of it the restart.

Step 1: Open Privacy & Security

Open the Settings app and tap Privacy & Security.

Step 2: Find Developer Mode

Scroll to the very bottom of Privacy & Security. Under the Security heading you will see Developer Mode. Tap it and turn the switch on.

Step 3: Restart the iPhone

iOS explains that Developer Mode lowers the phone's security and asks to restart. Tap Restart. The iPhone turns off and on again; nothing on it is erased or changed.

Step 4: Confirm and enter your passcode

When the phone has started again, unlock it. An alert asks whether to turn on Developer Mode. Confirm it and enter your passcode. That is it: the switch stays on until you turn it off.

What happens next

With Developer Mode on, the app you installed opens like any other. Depending on how it was signed, iOS may also ask you to trust the developer profile behind it, which for your own apps is your own Apple ID. That happens in Settings, General, VPN & Device Management, and our guide to the "Untrusted Developer" message walks through it.

From then on you do not touch either setting again for the same phone. New apps signed with the same Apple ID open straight away.

When you need Developer Mode with Borel

Borel builds your app in Swift on its own Mac, and you try it in the iPhone simulator in your browser. The simulator needs no settings at all. Developer Mode only comes in when you put the real app on your real phone.

Companion, a small app for Windows and Mac, signs your app with your Apple ID and installs it over a cable when you set it up, then over Wi-Fi. The download is free, and installing with it comes with Borel Pro. Apple's limits for a free Apple ID still apply: an app signed this way runs for seven days and Companion renews it while it runs. The full route is in installing your own app without the App Store review.

Is Developer Mode safe?

Developer Mode does not unlock your phone, root it or change iOS. It allows exactly one more kind of app to run: apps signed for development and installed directly. Those apps still live in their own sandbox, still ask for permission before using the camera, location or photos, and still follow the same rules as App Store apps once they run.

The risk is the same as any software you choose to install: only install apps you trust. If the only apps you put on the phone this way are ones you made yourself in Borel, the person you are trusting is you.

• What it changes: apps signed for development can open on the phone.
• What it does not change: App Store apps, your data, your passcode, Face ID, iCloud or backups.
• What Apple asks of you: a restart and your passcode, so the choice is always made on the phone.

How to turn Developer Mode off

Go back to Settings, Privacy & Security, Developer Mode and turn the switch off. iOS restarts the phone. Apps you installed yourself stay on the phone but no longer open until you turn it on again. App Store and TestFlight apps are not affected.

If you only wanted to try an app for a few days, turning it off afterwards is tidy. If you keep personal apps on the phone, leave it on.

Developer Mode with Borel Companion, from start to finish

Here is where Developer Mode fits when Companion puts a Borel app on your phone, so you know what to expect at each moment:

1. Build the app in Borel and try it in the simulator in your browser until it does what you want.
2. Download Borel Companion for Windows or Mac and sign in with your Apple ID. A free one works, and your password stays on your computer.
3. Plug the iPhone in with a cable, unlock it and tap Trust when it asks whether to trust this computer.
4. In Borel, press Run on your device. Companion signs the app with your Apple ID and installs it.
5. On the iPhone, turn on Developer Mode with the four steps above, if it is not on yet.
6. Open the app. If iOS asks, trust your Apple ID under Settings, General, VPN & Device Management.

After that, the cable is no longer needed: with the iPhone on the same Wi-Fi as your computer, Companion installs each new version while it runs, and the Borel app on your iPhone lists your apps with Download and Update buttons.

My app is on my iPhone now. Please add a small settings screen with:
1. A switch for a daily reminder, and a time picker for it
2. A button to clear all sample data
3. The app's version at the bottom
Keep the same look as the rest of the app.

Developer Mode on iPad

Every app Borel makes runs on iPad too, and the switch is in the same place on an iPad running iPadOS 16 or later: Settings, Privacy & Security, Developer Mode, then the restart and your passcode. Each device needs it turned on separately, and each counts on its own towards the devices your free Apple ID can install to.

Common mistakes

• Looking in the wrong place. Developer Mode is under Privacy & Security, at the very bottom, not under General or Developer.
• Skipping the restart. The setting only takes effect after the phone restarts and you confirm the alert.
• Confusing it with trusting the developer. Developer Mode lets development apps run at all; trusting the developer profile, under VPN & Device Management, is a separate step for a specific signer.
• Expecting it for TestFlight. TestFlight and App Store apps never need Developer Mode.
• Turning it off and forgetting. If your own app stops opening after you tidied up Settings, check this switch.
• Assuming an old iPhone has it. The setting is part of iOS 16 and later.

Why Apple added Developer Mode

Before iOS 16, an app signed for development could open as soon as it was installed. Apple added Developer Mode so that running such apps is always an explicit choice on the device, confirmed with a restart and the passcode. For people building their own apps it adds one minute, once; for everyone else it is a guard against being talked into installing something they do not understand.

The bottom line

Developer Mode is a four-step, one-time switch: Settings, Privacy & Security, Developer Mode, then restart and confirm. You need it to run apps you install yourself, and you never need it for the App Store or TestFlight.

If you are building an app with Borel, try it in the free simulator while you work, and turn Developer Mode on when it is time to live with the app on your own phone. Start with how to make an iPhone app with AI if you have not built one yet.

I know a switch called Developer Mode sounds like it is not meant for you. It is, if you want your own app on your own phone, and it takes a minute.

– Sigsten

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