How to Install IPA Files on iPhone and iPad
To install an IPA file on iPhone, the IPA must first be signed with a valid Apple Developer certificate and provisioning profile. After signing, the app can be installed through an on-device signer, OTA install link, or sideloading tool.
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 compatible 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. Only use IPA files from sources you trust and have permission to install. An IPA is executable code that runs on your device, and signing does not inspect or sanitize the app.
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 valid signing certificate and its private key, commonly packaged together in a password-protected .p12 file, plus a matching .mobileprovision profile that includes your device UDID. CertDrop prepares this device-matched certificate package for 360 days for $8.
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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:
Feather
Feather is a modern on-device signing app for signing compatible IPA files directly on iPhone. CertDrop certificate delivery includes a prepared Feather installation option, while the raw .p12, matching .mobileprovision profile, and password remain available if you prefer manual setup. See the Feather certificate guide.
- Platform: iOS only (no computer required)
- Best for: Straightforward installs, clean UI
- Certificate support: Full .p12 import
- Trust step required: Usually no extra trust step, but iOS behaviour can vary
ESign
ESign is one of the most widely used on-device signing apps. CertDrop certificate delivery includes a prepared ESign installation option. ESign also supports manual .p12 and mobileprovision import and can install IPAs directly from your Files app or via built-in sources.
- Platform: iOS only (no computer required)
- Best for: Users who want a mature, widely-tested tool
- Certificate support: Full .p12 import
- Trust step required: Usually no extra trust step, but iOS behaviour can vary
Scarlet
Scarlet is another popular on-device signer with a polished interface. Works the same way as Feather and ESign: import your CertDrop .p12 certificate, then tap to install IPA files from your Files app. No computer needed.
- Platform: iOS only (no computer required)
- Best for: Users who prefer Scarlet's interface
- Certificate support: Full .p12 import
- Trust step required: Usually no extra trust step, but iOS behaviour can vary
Install with your CertDrop delivery
If you bought your certificate from CertDrop, you do not need to search for Feather or ESign separately before first setup. The private delivery includes prepared installation options for both signers, while the raw certificate files remain available if you want to configure another compatible signer manually. If you use Feather specifically, see the Feather certificate guide for the P12 certificate and mobileprovision requirements.
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Open your private CertDrop delivery Open the CertDrop delivery email on the iPhone or iPad whose UDID was used for the order, then open the private install page from that message.
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Choose Feather or ESign Use the prepared Install Feather or Install ESign option from your CertDrop delivery instead of searching community download links.
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Finish the iPhone setup Follow the on-screen installation steps. Enable Developer Mode if iOS asks for it, then open the installed signer.
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Import and sign your IPA Add the IPA file you want to use in Feather or ESign and sign it with the certificate setup delivered for your device.
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Install and launch the app Install the signed IPA from the signer and open it from your home screen. If iOS shows an additional trust or Developer Mode prompt, follow the Settings prompt shown on the device.
What UDID Is and How to Find It
UDID stands for Unique Device Identifier. It identifies a specific iPhone or iPad for device registration, and its exact format varies by device generation. For normal development signing, Apple uses registered device UDIDs inside provisioning profiles, so the target device must be included in the profile used to sign the app.
Your UDID does not change unless you replace your device. The easiest way to find it:
- If you are already on the iPhone or iPad, open CertDrop Get UDID in Safari. If you are on a computer, open the same tool and click Show QR code.
- On a computer, scan the QR code with the Camera app on the iPhone or iPad you want to register.
- Approve and install the temporary CertDrop profile on that iPhone or iPad when prompted.
- Your UDID appears automatically in the Get UDID flow. Copy it carefully or continue directly to certificate checkout.
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 containing the registered device and permitted signing configuration
- 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. If you do not have it yet, get your UDID here.
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.
Get the Certificate You Need
CertDrop issues Apple Developer certificates registered to your UDID. One certificate, compatible IPA, 360 days — $8. Delivered by email, no Mac required.
Common questions
Why will an IPA not install on my iPhone?
The IPA may be unsigned, signed with the wrong certificate, missing your UDID in the mobileprovision profile, incompatible with your iOS version, or opened outside Safari.
Can I install an IPA without a computer?
Yes. If the IPA is signed correctly, you can install it on iPhone through an OTA install link or an on-device signer app.
Do I need to sign the IPA first?
Yes. iOS will not normally install or open an unsigned IPA. You need a signed IPA created with a valid .p12 certificate, mobileprovision profile, and password.
Do CertDrop customers need to find Feather or ESign separately?
No. Your private CertDrop delivery includes prepared installation options for Feather and ESign. The raw certificate files are still included if you prefer manual setup.
Check your setup before you lose time.
Use the free CertDrop tools to check certificate files, IPA compatibility, and iPhone setup steps before ordering or signing.