What Is a Repo for Scarlet iOS? How Repos Work (2026)
A repo (short for repository) in Scarlet iOS is an online list of apps that you add to Scarlet by its URL. Once it is added, every app in that list shows up in Scarlet and can be installed on your iPhone or iPad without a computer or a jailbreak. This page explains what a repo is, what is inside one, how Scarlet uses it and how it differs from a Cydia or AltStore source. Last checked: October 27, 2026.
Looking for repos to add, or for help adding one? See Scarlet iOS repos: how to add, manage and fix sources. For a reviewed list of IPA sources and their risks, read our guide to the best IPA libraries and repositories for iOS.
What Is a Repo for Scarlet?
Scarlet iOS is an on-device app installer: an alternative to the App Store and to Cydia that installs IPA files (iOS app packages) and signs them with a certificate it provides. Scarlet comes with its own built-in library of apps. A repo is any extra list of apps you connect to it.
Technically, a repo is a single JSON file on a web server. It does not hold the apps itself; it holds a description of each app and a link to where its IPA file can be downloaded. Anyone can publish one: an app developer sharing their own app, a community collecting many apps, or you, for your own files.
An earlier version of this page described Scarlet itself as a “repository system” for paid apps and listed repos such as “ScarletAppRepo” or “ScarletThemes”. Those names did not match any real source we could find, so we removed them.
What Is Inside a Scarlet Repo?
A Scarlet repo file has two parts:
- Repo details in a
METAsection: the repo’s name (repoName) and icon (repoIcon). This is what Scarlet shows in your Sources list. - A list of apps. Each entry describes one app.
The fields of an app entry, as used in published Scarlet-format repos, are:
| Field | What it holds |
|---|---|
name | The app’s name |
version | The version of the IPA |
down | The download link to the IPA file |
bundleID | The app’s bundle identifier, such as com.example.app |
dev | The developer’s name |
icon | A link to the app icon |
category | A category such as games or utilities |
description | A short description |
screenshots | Links to screenshots |
contact | The developer’s website or social links |
You can see this for yourself: open a repo URL in Safari and you will see the raw file. The AppTesters repo, for example, opens with its name and META section followed by thousands of app entries.
How Scarlet Uses a Repo
- You add the repo URL in Scarlet’s Sources (or Repos) tab.
- Scarlet downloads the JSON file and shows its apps with their names, icons and descriptions.
- When you install an app, Scarlet downloads the IPA from the link in the entry.
- Scarlet signs the IPA with its certificate and installs it, the same way it installs apps from its built-in library.
Two things follow from this. First, a repo is only as trustworthy as the people who run it: Scarlet installs whatever file the link points to. Second, the repo does not decide how long an app keeps working. If Apple revokes the signing certificate, apps stop opening no matter which repo they came from.
Scarlet Repos vs Cydia Repos vs AltStore Sources
| Scarlet repo | Cydia repo | AltStore source | |
|---|---|---|---|
| What it lists | IPA apps | .deb packages (tweaks, themes, apps) | IPA apps |
| Needs a jailbreak | No | Yes | No |
| File format | JSON with META and app entries | Packages and Release files | JSON with its own field names |
| Signing | Scarlet’s certificate | Not needed on a jailbroken device | Your Apple ID or developer certificate |
The formats overlap. Some repos write one file with both sets of field names (for example down next to downloadURL, and bundleID next to bundleIdentifier), so the same URL works in Scarlet and in AltStore-style installers. AppTesters does this. A Cydia repo is a different thing entirely: its tweaks need a jailbroken device and cannot be added to Scarlet.
Can You Make Your Own Scarlet Repo?
Yes. Write a JSON file with a META section and one entry per app using the fields above, host the IPA files and the JSON somewhere that serves them over HTTPS (GitHub is a common choice), and add the JSON file’s URL in Scarlet. Only share IPA files you have the right to distribute.
Frequently Asked Questions
Is a repo the same as Scarlet?
No. Scarlet is the app that installs IPA files. A repo is a list of apps that Scarlet can read. Scarlet works without any extra repo thanks to its built-in library.
Are Scarlet repos safe?
It depends on who runs them. A repo can point to any file, including modified or altered apps. Use well-known sources, keep your list short and read is iOS sideloading safe before adding unknown ones.
Why is my Scarlet repo not working?
Usually the URL has changed, the repo is offline or the file is not valid JSON. Open the URL in Safari to check, then see the troubleshooting steps in our Scarlet repos guide.
Can I use several repos at once?
Yes. Apps from all added repos appear in Scarlet alongside the built-in library.
Do repos protect apps from being revoked?
No. Revokes happen to the signing certificate, not to the repo. A repo cannot stop an app from being revoked.