How to Install Scarlet iOS on Your iPhone or iPad

This guide walks you through installing Scarlet iOS on an iPhone or iPad, step by step, from the first tap in Safari to opening your first app. It covers the direct install most people use, the computer-based options, and the errors you are most likely to meet on the way. If you only want to know which version is current and where to download it safely, see our Scarlet iOS download page instead.

You can start the install from our Scarlet iOS install page.

What Scarlet iOS Is, in One Paragraph

Scarlet describes itself as an App Store and Cydia alternative for iPhone and iPad. It is an app installer: you use it to install apps that are not on the App Store, from its built-in library, from third-party repositories you add, or from IPA files you already have. It does not need a jailbreak. Apps are installed with certificate signing, which also means Apple can revoke the certificate, so it helps to know the fix before you need it. For the full picture, read what Scarlet iOS is and how it works.

Before You Install: Checklist

• iOS version: Scarlet is confirmed to work on iOS 14 through iOS 26. iOS 27 is out (Apple released it on September 14, 2026), but Scarlet support on it is only reported by third parties and not officially confirmed. Check your version in Settings, General, About.
• Browser: use Safari for the direct install. Other browsers on iPhone often cannot open app install links.
• Storage: the app is about 35 MB, so a little free space is enough; the apps you install later need their own space.
• Connection: a stable Wi-Fi or mobile data connection while the app downloads.
• Passcode: you will need your device passcode for the trust step.

Method 1: Direct Install on the iPhone (No Computer)

The official Scarlet site offers two ways to set it up: a direct install on the device and a Scarlet computer method. The direct install is the one most people use, because it needs no computer or cable, and it signs with a shared certificate instead of your Apple ID.

Step 1: Start the install in Safari

1. Open Safari on your iPhone or iPad.
2. Go to our Scarlet iOS install page and tap the install button.
3. Follow the on-screen steps. When iOS asks whether you want to install Scarlet, tap Install.
4. Go to your home screen and wait for the Scarlet icon to finish downloading.

Step 2: Trust the developer profile

The first time you tap the Scarlet icon, iOS will usually show an “Untrusted Enterprise Developer” message. That is expected: iOS blocks apps from a new developer until you approve them once.

1. Open Settings, then General, then VPN and Device Management.
2. Under Enterprise App, tap the developer profile that belongs to Scarlet.
3. Tap Trust, then confirm.
4. Go back to the home screen and open Scarlet.

If the profile does not appear or the Trust button does nothing, see how to trust enterprise developer certificates on iPhone and how to fix the Untrusted Developer error.

Step 3: Install your first app

1. Open Scarlet and browse or search the built-in library.
2. Tap an app, then tap Install, and confirm the iOS prompt.
3. Wait for the icon to finish downloading on your home screen.
4. If the new app asks to be trusted, repeat the trust step for its profile.

To install an IPA file you already have instead of a library app, follow our guide to sideloading IPA files with Scarlet iOS.

Method 2: Install With a Computer

If the direct install is not working for you, a computer gives you other routes. They take longer to set up and come with their own limits.

The Scarlet computer method

The official Scarlet site offers a computer-based setup as its second option. Use the instructions on the official site for it, since they change with new releases.

Sideloadly or AltStore with your Apple ID

Both tools can install an IPA file signed with your own Apple ID, which means Apple’s revocation of an enterprise certificate does not affect that copy. If you have the Scarlet IPA file:

1. Install Sideloadly (Windows or Mac) or AltServer and AltStore on your computer and iPhone.
2. Connect your iPhone and load the Scarlet IPA into the tool.
3. Sign in with your Apple ID when asked. Use an Apple ID you are comfortable using for this.
4. On iOS 16 or later, turn on Developer Mode when iOS asks for it; our guide to Developer Mode on iPhone explains why.

The limits: with a free Apple ID, apps signed this way expire after 7 days and must be re-signed, and only 3 such apps can be active at once. Our comparison of AltStore vs Scarlet iOS vs Sideloadly covers the trade-offs.

Method 3: TrollStore (Older iOS Versions Only)

TrollStore installs apps permanently, without certificates that can be revoked, but it only works on iOS 14.0 to 16.6.1 and on iOS 17.0. It does not work on iOS 16.7 or later 16.x releases, iOS 17.0.1 or later, or any newer major version. If your device is on a supported version and already has TrollStore, you can open the Scarlet IPA with TrollStore and install it from there. See Scarlet iOS vs TrollStore for when each makes sense.

Which Method Should You Use?

Method	Computer	Apple ID	Main catch
Direct install	No	No	Certificate can be revoked
Scarlet computer method	Yes	See official site	Needs a computer
Sideloadly or AltStore	Yes	Yes	7-day re-signing, 3 apps on a free account
TrollStore	Sometimes	No	Only iOS 14.0 to 16.6.1 and 17.0

For most people the direct install is the right start. Keep a computer-based method in mind as a backup for when a revocation happens.

Troubleshooting the Install

“Untrusted Enterprise Developer”

You have not trusted the profile yet. Follow Step 2 above.

“Unable to Install Scarlet”

Make sure you are in Safari, check your connection, and try again later. This message can also appear while a certificate is being replaced.

“Unable to Verify App”

iOS could not check the app’s certificate, often because of a network problem or a revoked certificate. See how to fix Unable to Verify App.

Scarlet installed but will not open

If it worked before and suddenly stopped, the certificate was most likely revoked. Our guide on what to do when the Scarlet certificate is revoked covers the fix, and Scarlet app crashes on launch covers other causes. For everything else, start with the Scarlet iOS troubleshooting master guide.

After You Install

• Add repositories to reach more apps; our list of IPA libraries and repositories is a good start.
• Check files from unknown sources before installing them: how to scan IPA files for malware.
• Keep apps up to date by hand, since sideloaded apps do not update themselves: how to keep sideloaded apps updated.
• After a major iOS update, update Scarlet as well, since older versions may not work on a new iOS release.

Frequently Asked Questions

Do I need a computer to install Scarlet iOS?

No. The direct install works from Safari on the iPhone or iPad itself. A computer is only needed for the alternative methods.

Do I need an Apple ID?

Not for the direct install. Sideloadly and AltStore need one, because they sign the app with your account.

Does Scarlet need Developer Mode?

Not for the direct install, which uses the profile trust step instead. Developer Mode is only needed when an app is signed with your own Apple ID on iOS 16 or later.

Is installing Scarlet safe?

Scarlet itself does not jailbreak or modify iOS. The main risks come from where apps are downloaded: use the official site or our install page for Scarlet, and trusted sources for the apps you install with it. Our sideloading security guide covers the details.

Why did Scarlet stop working after it was installed?

Usually because Apple revoked the certificate it was signed with. That is a limit of the method, not a fault on your device; reinstalling once a new certificate is available fixes it.