AltStore vs Scarlet iOS vs Sideloadly: Ultimate Guide

ByScarlet iOS Team Updated on

AltStore, Scarlet iOS and Sideloadly are the three names most people meet first when they want to install apps outside the App Store. They solve the same problem in very different ways: Scarlet works entirely on the iPhone with a shared certificate, while AltStore and Sideloadly sign apps with your own Apple ID from a computer. This guide compares them on every point that matters in daily use, so you can pick one, or the combination that suits you.

Quick Summary

  • Scarlet iOS: no computer, a shared certificate instead of your Apple ID, built-in app library. Easiest to start with, but a certificate revocation stops everything until a new build is out.
  • AltStore: needs a computer running AltServer and your Apple ID. Apps refresh over Wi-Fi every 7 days and are not affected by shared revocations.
  • Sideloadly: a signing tool for Windows and Mac. You bring the IPA, it signs and installs it with your Apple ID. Most control; its optional auto-refresh re-signs apps while the computer can reach the iPhone.

Side-by-Side

Scarlet iOS AltStore Sideloadly
Computer No Yes Yes
Apple ID No Yes Yes
App library Built in, plus repos Sources (repos) None, bring your IPA
Apps last Until revoked 7 days, auto refresh 7 days, manual or auto refresh
App limit (free) None 3 active 3 active

How Each Tool Signs Apps

Scarlet iOS

Scarlet is installed from Safari and signs apps with an enterprise certificate that many users share. You browse its library or add repos, tap install, and the app lands on your home screen. The first time, you trust the developer in Settings > General > VPN & Device Management. Because the certificate is shared, Apple can revoke it, and then Scarlet and its apps stop opening until a newly signed build is available. Support is confirmed up to iOS 26; iOS 27 support is reported by third parties but not officially confirmed.

To try it, install Scarlet iOS from our install page.

AltStore

AltStore is installed on the iPhone with the help of AltServer, a companion app for Mac or Windows. AltServer signs apps with a certificate created from your Apple ID, so each app is signed for your device only. With a free Apple ID that signature lasts 7 days; AltStore refreshes it automatically when your iPhone and computer are on the same Wi-Fi and AltServer is running. A paid Apple Developer account ($99 per year) extends signatures to a year.

Sideloadly

Sideloadly is a desktop app for Windows and Mac. You sign in with your Apple ID, drop an IPA file in, connect the iPhone and it signs and installs the app. It works with free and paid Apple Developer accounts and has advanced options such as changing an app’s name or bundle ID, so you can install a second copy of an app. With a free Apple ID apps must be re-signed every 7 days, either by hand or with its optional auto-refresh, which works while the computer can reach the iPhone over USB or Wi-Fi. Our Sideloadly guide covers setup and common errors step by step.

Setup Compared

Scarlet iOS

  1. Open the install page in Safari on your iPhone and tap Install
  2. Trust the developer in Settings > General > VPN & Device Management
  3. Open Scarlet. A few minutes in total, no computer

Full steps: how to install Scarlet iOS.

AltStore

  1. Install AltServer on your Mac or Windows PC (Windows also needs iTunes and iCloud from Apple’s website)
  2. Connect the iPhone by cable and install AltStore from AltServer with your Apple ID
  3. On iOS 16 and later, turn on Developer Mode and trust your Apple ID in VPN & Device Management

Sideloadly

  1. Install Sideloadly on your computer (Windows also needs iTunes and iCloud from Apple’s website)
  2. Connect the iPhone, sign in with your Apple ID and drag in the IPA file
  3. Turn on Developer Mode (iOS 16 and later) and trust your Apple ID on the iPhone

Finding Apps

  • Scarlet iOS: a built-in library plus third-party repos and your own IPA files, all browsable on the iPhone.
  • AltStore: a small set of official apps plus third-party sources you can add. You can also install your own IPA files.
  • Sideloadly: no library at all. You need the IPA file first; see our list of IPA libraries and repositories.

Keeping Apps Working

  • Scarlet iOS: nothing to do day to day. When Apple revokes the certificate, every app stops at once; you reinstall Scarlet when a new build is out and reinstall your apps over the old copies. See what to do when the certificate is revoked.
  • AltStore: refreshes every 7 days in the background, as long as AltServer is running on the same network. If you miss the window, the apps stop until you refresh. If AltStore cannot reach AltServer, see AltStore and AltServer errors.
  • Sideloadly: re-sign each app before the 7 days run out, or tick auto-refresh when you sideload; the Sideloadly Daemon then re-signs apps while the computer is on and can reach the iPhone over USB or the same Wi-Fi.

Privacy and Your Apple ID

  • Scarlet iOS: does not use your Apple ID at all. The trade-off is that you rely on a certificate and an installer you do not control.
  • AltStore and Sideloadly: sign in to Apple with your Apple ID to create the signing certificate. Many people use a separate free Apple ID for sideloading so their main account is never involved.

Whatever tool you use, the bigger risk is the IPA file itself. Read is iOS sideloading safe before you install modified apps.

Cost

  • Scarlet iOS: free
  • AltStore: free with a free Apple ID. In the EU, Japan and Brazil, AltStore PAL is a separate marketplace version with its own terms; check altstore.io for its current price (see our AltStore PAL guide)
  • Sideloadly: free
  • For AltStore and Sideloadly, a paid Apple Developer account ($99 per year) removes the 7-day and 3-app limits

Which One Should You Use?

  • No computer: Scarlet iOS, the only one of the three that works without one worldwide (in the EU, Japan and Brazil, AltStore PAL also installs without a computer)
  • A computer at home and 1 to 3 apps that must keep working: AltStore
  • One specific IPA, or advanced signing options: Sideloadly
  • The most resilient setup: Scarlet for convenience plus AltStore or Sideloadly for the apps you cannot lose during a revocation

Want only two of them head to head? Read Scarlet iOS vs AltStore. To set up SideStore, see how to install SideStore on iPhone. For more free tools, including SideStore and TrollStore, see free sideloading tools compared. To see Scarlet against every other installer at once, read Scarlet iOS vs every alternative.

Frequently Asked Questions

Which is easiest for beginners?

Scarlet iOS: it installs from Safari in a few minutes with no computer or Apple ID.

Which is most reliable?

AltStore and Sideloadly, because apps signed with your own Apple ID are not hit by shared certificate revocations. The price is the 7-day refresh.

Can I use all three on one iPhone?

Yes. They do not conflict. Apps signed with your Apple ID count toward the 3-app limit; apps from Scarlet do not.

Do I need Developer Mode?

For AltStore and Sideloadly on iOS 16 and later, yes. Scarlet does not need it; it needs the developer to be trusted in VPN & Device Management instead.

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