How to Install IPA Files on iPhone and iPad

An IPA file is the standard package format for iOS apps. Unlike Android, iOS doesn't let you install IPAs by simply tapping them — every IPA must be cryptographically signed with a valid Apple Developer certificate before iOS will accept it. With a paid developer certificate and an on-device signing app like Feather, ESign, or Scarlet, you can install any IPA directly on your iPhone without a computer. This guide covers everything from certificate setup to app launch.

What Is an IPA File?

An IPA file is a compressed archive containing an iOS app's compiled binary, assets, and metadata. It's the delivery format for iOS applications — the App Store delivers a signed IPA to your device every time you install an app. The difference with sideloading is that you're sourcing the IPA yourself and signing it with your own certificate instead of Apple's distribution signing.

IPA files are distributed by developers through GitHub releases, community forums, and independent websites. Some apps are no longer on the App Store but still circulate as IPA files. Others are patched or modified versions of existing apps. Always download IPAs from sources you have reason to trust — an IPA is executable code that runs on your device.

Why You Need a Signing Certificate

iOS enforces mandatory code signing at the kernel level. When you tap an app icon, the OS verifies the app's cryptographic signature against Apple's certificate authority before executing a single line of code. A missing or invalid signature produces an immediate rejection — you'll see "Unable to Install" or the app will simply refuse to launch.

To sign an IPA, you need a developer certificate (.p12 file) registered to your device's UDID. CertDrop provides exactly this: an individual Apple Developer certificate tied to your specific device, valid for 360 days, for $12 USDT.

Three On-Device Signing Apps for Paid Certificates

With a paid developer certificate from CertDrop, you can sign and install IPA files directly on your iPhone — no Mac, no USB cable, no computer at all. Here are the three best on-device signing apps:

Step-by-Step: Installing an IPA with Feather (or ESign/Scarlet)

The process is identical across Feather, ESign, and Scarlet. Here's the complete flow:

1. Get your UDID and order your certificate Visit udid.tech on your iPhone to find your UDID. Then go to certdrop.app, enter your UDID and email, complete the payment. You'll receive a .p12 certificate file and password by email within minutes.
2. Save your .p12 certificate to Files Open the CertDrop email on your iPhone. Long-press the .p12 attachment and choose "Save to Files." Place it somewhere easy to find, like your iCloud Drive or Downloads folder.
3. Install your signing app Download Feather, ESign, or Scarlet from their respective community sources. These apps are available as IPA files themselves — search in iOS sideloading communities (Reddit, Discord, etc.) for the current trusted download link for your preferred app.
4. Import your CertDrop certificate into the signing app Open your signing app and navigate to the certificate or settings section. Tap "Import Certificate" (or equivalent), browse to your .p12 file in Files, select it, and enter the password from your CertDrop email. The certificate will appear as active in the app.
5. Import your IPA file Save your IPA to the Files app (via AirDrop, Safari download, or cloud storage like iCloud/Dropbox). In your signing app, tap the "+" or Import button, browse to the IPA file, and select it.
6. Sign and install Tap "Install" or "Sign & Install" in the signing app. It will sign the IPA with your CertDrop certificate and install it directly to your home screen. The process takes a few seconds.
7. Launch your app Find the app on your home screen and tap to open. Open the app from your home screen. If iOS asks you to trust the developer profile, follow the Settings prompt and trust the profile linked to your certificate.

What UDID Is and How to Find It

UDID stands for Unique Device Identifier. It's a 25-character alphanumeric string that identifies your specific iPhone or iPad hardware. Apple uses it to bind developer certificates to specific physical devices — a certificate registered to one UDID will not work on a different device.

Your UDID does not change unless you replace your device. The easiest way to find it:

1. Open Safari on your iPhone (not Chrome — Safari is required)
2. Go to udid.tech
3. Tap the button to download a configuration profile
4. Install the profile in Settings when prompted
5. Your UDID appears on the udid.tech page — copy it carefully

How Signing Works

When a signing app like Feather or ESign processes your IPA, it does three things:

• Replaces the existing signature — strips the original developer signature from the IPA (which only authorised the original developer's devices) and replaces it with yours
• Embeds your provisioning profile — inserts the .mobileprovision file that authorises your specific UDID
• Signs with your private key — uses the private key from your .p12 certificate to cryptographically sign the binary

The result is an IPA that iOS recognises as trusted because it chains back through your certificate to Apple's certificate authority. The whole process takes a few seconds and happens entirely on your device.

Common IPA installation problems

If a signed IPA does not install, the problem is usually one of a few predictable issues. Start with the error message shown by iOS, then check the certificate, provisioning profile, device UDID, and IPA file.

Unable to Install App

This usually means iOS rejected the signed package. Common causes include a missing UDID, expired certificate, revoked certificate, damaged IPA, or provisioning profile mismatch.

Integrity could not be verified

This can happen when the signing certificate is no longer trusted, the profile is invalid, or the app was not signed correctly. Try signing the IPA again and confirm that the certificate and provisioning profile belong together.

App installs but will not open

If the app installs but crashes or closes immediately, the IPA itself may have compatibility issues. Signing allows iOS to install the app, but it cannot fix broken app code, unsupported iOS versions, server-side restrictions, or missing app dependencies.

App disappears or stops working later

This may happen if the certificate expires, is revoked, or the app was installed with a short-lived signing method. A valid paid developer certificate normally lasts longer than free Apple ID signing, but no signing method can guarantee that every app will work forever.

IPA installation FAQ

Can I install an IPA file without signing it?

No. On a normal iPhone or iPad, the IPA must be signed before iOS will install and run it.

Do I need a computer to install IPA files?

Not always. With a valid certificate and an on-device signer such as Feather, ESign, or Scarlet, you can sign and install IPAs directly on the iPhone. A computer is only needed for some manual workflows.

Do I need my UDID?

For a standard Apple Developer certificate, yes. The provisioning profile normally needs to include the UDID of the iPhone or iPad where the app will be installed.

Is installing an IPA the same as jailbreaking?

No. Installing a signed IPA does not jailbreak the device. It uses Apple's code-signing system to allow the app to run on a registered device.