Introduction

The iOS equivalent of an APK is an IPA file. IPA stands for iOS App Store Package. Just as Android uses .apk files to package and distribute apps, iOS uses .ipa files. Both are compressed archives containing the app binary, resources, and metadata, but they operate under very different security models and distribution rules.

What Is Inside an IPA File

An IPA file is a ZIP archive with a specific internal structure. If you rename an .ipa file to .zip and extract it, you will find:

1MyApp.ipa
2  └── Payload/
3      └── MyApp.app/         # The actual application bundle
4          ├── MyApp           # Compiled executable binary
5          ├── Info.plist      # App metadata (version, bundle ID, permissions)
6          ├── Assets.car      # Compiled asset catalog (icons, images)
7          ├── Base.lproj/     # Localization resources
8          ├── _CodeSignature/ # Code signature files
9          └── embedded.mobileprovision  # Provisioning profile

Key files explained

APK vs IPA: Side-by-Side Comparison

How IPA Distribution Works

Unlike Android, where you can download an APK from any website and install it, iOS tightly controls how apps reach devices.

1. App Store (primary distribution)

The standard path for consumer apps:

1. Developer builds the app in Xcode
2. Xcode creates an archive (.xcarchive)
3. Developer uploads to App Store Connect
4. Apple reviews the app (typically 24-48 hours)
5. Approved app appears on the App Store
6. Users download and install through the App Store app

Users never see or handle the IPA file directly.

2. TestFlight (beta testing)

TestFlight is Apple's official beta distribution platform:

1Developer uploads build to App Store Connect
2  → Invites testers (up to 10,000 external testers)
3  → Testers install via the TestFlight app
4  → Beta builds expire after 90 days

This is the standard way to distribute pre-release builds without going through full App Store review.

3. Ad Hoc distribution (limited testing)

For distributing to specific devices without TestFlight:

• Limited to 100 devices per device type per year (100 iPhones, 100 iPads, etc.)
• Each device's UDID must be registered in the developer portal
• The provisioning profile must include the target device

1# To find a device's UDID, connect it and run:
2xcrun xctrace list devices
3
4# Or use Finder/iTunes: click the device, click the serial number to reveal UDID

4. Enterprise distribution (internal business apps)

Organizations with an Apple Developer Enterprise Program membership ($299/year) can distribute apps internally without the App Store:

• No device limit
• No App Store review
• Apps can be installed via MDM (Mobile Device Management) or a private download link
• Strictly for internal use. Apple revokes certificates if enterprise distribution is used publicly.

5. Direct distribution in the EU (2024+)

Under the Digital Markets Act, Apple now allows alternative app marketplaces in the European Union. Developers can distribute apps outside the App Store, though they must still use Apple's notarization process.

Code Signing: Why IPA Security Is Different

The fundamental difference between APK and IPA security is who controls the signing keys.

Android approach

Developers generate their own signing keys. Any developer can sign any APK. Google Play does additional checks, but the signing infrastructure itself is open:

# Android: developer generates their own key
keytool -genkey -v -keystore my-release-key.jks -keyalg RSA -keysize 2048

iOS approach

All code signing goes through Apple. You cannot create a valid signing certificate without an Apple Developer account ($99/year), and every certificate is tied to your identity:

1# iOS: Xcode handles signing, but under the hood:
2# 1. Certificate Signing Request (CSR) sent to Apple
3# 2. Apple issues a development or distribution certificate
4# 3. Provisioning profile binds: certificate + app ID + device UDIDs + entitlements
5# 4. codesign signs the binary with the certificate
6codesign -s "Apple Distribution: Your Name (TEAM_ID)" MyApp.app

This chain means Apple can revoke any app at any time by revoking its certificate. It also means sideloaded apps without a valid certificate simply will not launch.

Provisioning profiles in detail

A provisioning profile is a signed plist file from Apple that answers four questions:

1. Who can sign this app (which certificates)
2. What app this is (bundle identifier)
3. Where it can run (which device UDIDs, or "any device" for App Store)
4. What it can do (entitlements: push notifications, iCloud, HealthKit, etc.)

# Inspect a provisioning profile
security cms -D -i embedded.mobileprovision

Building an IPA File

From Xcode (GUI)

1. Select your target and set the scheme to "Any iOS Device"
2. Product, then Archive
3. In the Organizer window, click "Distribute App"
4. Choose distribution method (App Store, Ad Hoc, Enterprise, Development)
5. Xcode generates the signed IPA

From the command line

1# Build the archive
2xcodebuild archive \
3  -scheme MyApp \
4  -archivePath build/MyApp.xcarchive \
5  -sdk iphoneos
6
7# Export the IPA
8xcodebuild -exportArchive \
9  -archivePath build/MyApp.xcarchive \
10  -exportPath build/ \
11  -exportOptionsPlist ExportOptions.plist

The ExportOptions.plist specifies the signing identity, provisioning profile, and distribution method:

1<?xml version="1.0" encoding="UTF-8"?>
2<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
3  "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
4<plist version="1.0">
5<dict>
6    <key>method</key>
7    <string>app-store</string>
8    <key>teamID</key>
9    <string>YOUR_TEAM_ID</string>
10</dict>
11</plist>

Modern Alternatives: App Clips and App Bundles

App Clips (iOS 14+)

App Clips are lightweight portions of an app (under 15 MB) that users can launch without installing the full app. They are triggered by NFC tags, QR codes, or links. Think of them as iOS's answer to Android Instant Apps.

xcframework bundles

For library distribution, Apple now uses .xcframework bundles instead of .framework files. These support multiple architectures (ARM64 for devices, x86_64 for simulators) in a single package.

Common Pitfalls

• Assuming you can sideload IPAs like APKs. iOS does not allow arbitrary app installation. Even developer-signed apps expire after 7 days (free account) or 1 year (paid account).
• Confusing .app bundles with .ipa files. Xcode simulators use .app bundles directly. IPA files are for real devices and contain a .app bundle inside the Payload directory.
• Enterprise certificate abuse. Using an enterprise certificate to distribute apps to the public violates Apple's terms and results in certificate revocation, which kills every app signed with it.
• Forgetting that provisioning profiles expire. Profiles are valid for 1 year. Apps stop launching on devices once the embedded profile expires. Automatic signing in Xcode handles renewal, but manual profiles need attention.
• Trying to inspect an IPA without renaming it. IPA files are ZIP archives. Rename to .zip to extract and inspect the contents.

Summary

• The iOS equivalent of an APK is an IPA (iOS App Store Package).
• Both are ZIP archives containing app binaries, resources, and metadata, but IPAs require Apple-issued code signing.
• iOS distribution is controlled: App Store, TestFlight, Ad Hoc (100 devices), and Enterprise (internal only).
• Android allows self-signed apps and open sideloading. iOS requires Apple's certificate chain for every installation.
• IPA files contain the Mach-O binary, Info.plist, provisioning profile, and code signature.
• Build IPAs from Xcode or the command line using xcodebuild archive and xcodebuild -exportArchive.
• You cannot install an IPA on a device without a valid provisioning profile that includes that device (or an App Store/Enterprise distribution profile).