What is the IPA file format?
.ipa (iPhone Application) is a ZIP archive that contains an application built for iOS or iPadOS devices such as iPhone or iPad. An .ipa file can be unpacked using any ZIP-compatible archive manager - renaming it to .zip is enough to inspect its contents - however the file is distributed and used in its packed form. Internally it holds a Payload/ directory with a single AppName.app bundle containing a Mach-O executable, an Info.plist manifest, app resources, and a _CodeSignature/ folder for integrity verification.
.ipa files are installed on a device via the App Store, TestFlight, or tools such as Xcode and Apple Configurator. Installation requires a valid Apple code signature and a provisioning profile matching the target device. Unlike the old iTunes workflow - which stored apps in a Mobile Applications/ folder - modern installation goes directly through the device or a management tool. .ipa files install exclusively on iOS and iPadOS and cannot be run on macOS.
Since iOS 9 (2015), Apple applies app thinning, so a downloaded .ipa contains only the arm64 slice relevant to the target device. App Store builds are FairPlay DRM-encrypted; developer and ad-hoc builds are signed only. There are many types of .ipa applications, including games, utilities, and productivity tools.
Security & safety
RISK: HIGHSideloaded IPAs bypass Apple's App Store review, which is the main iOS malware safeguard. Risks: re-signing tools require your Apple ID (use app-specific passwords; revoked certificates can brick the app), pirated/"modded" IPAs from unofficial repos can carry malware or steal credentials, and enterprise-signed apps can be revoked by Apple at any time. Only sideload from sources you trust, prefer TestFlight for betas, and remember free-account sideloads expire after 7 days.
Format details
in a nutshellPrograms that open IPA files
Windows2 apps
Sideloadly
Free Install iTunes/iCloud drivers, plug in the iPhone, drop the .ipa into Sideloadly, sign in, and install.
7-Zip (inspect only)
Open-source Right-click -> Open archive to browse the .ipa contents (it's a ZIP). Does NOT install the app. 
macOS3 apps
Xcode
Free Use Devices & Simulators -> Installed Apps -> '+' to install an .ipa onto a connected development device.
Apple Configurator
Free Connect the iPhone/iPad, drag the .ipa onto the device to install (useful for ad-hoc/enterprise builds and MDM).
Sideloadly
Free Connect the device, select the .ipa, sign in with your Apple ID, and Sideloadly signs and installs it.
TestFlight
Free For beta builds: open the TestFlight invite, then install the app from within TestFlight (the .ipa is delivered through Apple, you don't handle the file directly).
AltStore
Free Sideload the .ipa to your own iPhone using your Apple ID; AltStore re-signs it and refreshes the 7-day free-account signature. Needs the AltServer helper. Technical details
deep spec| Container format | Standard ZIP archive (PK format) |
| Magic bytes | 50 4B 03 04 at offset 0 ("PK" - ZIP local file header) |
| MIME type | application/octet-stream; also application/x-itunes-ipa |
| Internal structure | Payload/<AppName>.app bundle containing Mach-O binary, Info.plist, resources, and _CodeSignature/ |
| Compression | DEFLATE per entry (standard ZIP compression) |
| Byte order | Little-endian (ZIP structure and arm64 Mach-O executable inside) |
| Supported CPU architecture | arm64 (App Store thinned builds); universal developer archives may include arm64e |
| DRM / encryption | FairPlay DRM on App Store binaries (Mach-O encrypted at rest, decrypted at runtime per Apple ID); developer/ad-hoc builds: signed only, no DRM |
| Code signing | Mandatory; enforced via _CodeSignature/CodeResources; iOS/iPadOS refuses unsigned or tampered apps |
| Provisioning profile | Embedded as embedded.mobileprovision; specifies allowed device UDIDs, entitlements, and signing certificate |
| App thinning | Introduced iOS 9 / Xcode 7 (2015); downloaded .ipa is device-specific slice, not a universal bundle |
| Typical file size | 5 MB - 4 GB; App Store enforces a 4 GB cap on the total app bundle |
| Distribution channels | App Store, TestFlight, Ad Hoc, Enterprise (in-house), Developer (via Xcode or Apple Configurator) |
| Target platforms | iOS and iPadOS only; not installable on macOS or Android |
| Info.plist declarations | CFBundleIdentifier, MinimumOSVersion, UIRequiredDeviceCapabilities, and entitlements validated at install time |
| Released | 2008 (iPhone OS 2.0, with the App Store) |
| Latest version | Current packaging via Xcode / App Store Connect (thinned .ipa per device since app thinning, iOS 9, 2015) |
| Specification | developer.apple.com |
IPA conversions
Community Q&A
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