Sideloading on Apple TV

What you need to install apps on an Apple TV, how to find its UDID, and which tools send apps to it from a phone or computer.

An Apple TV cannot sign or install an IPA itself. Another device signs the app and sends it to the TV over your home network.

What you need

You need	Why
A certificate registered to the Apple TV's own UDID	A certificate for your iPhone does not cover the TV. Each Apple TV needs its own.
An IPA built for tvOS	iPhone IPAs do not run on Apple TV. Download pages list the tvOS file separately.
An iPhone, iPad, Mac or PC on the same network	It signs the app and sends it to the TV.

cert.fish certificates are registered to one iPhone, so they do not work on an Apple TV. Providers that state Apple TV support include FlareStore, SwiftSign, AppleP12 and Signulous. Ask for an Apple TV certificate when ordering. Compare terms in certificate providers compared.

1. Find the Apple TV's UDID

The UDID is the TV's unique device ID. The provider registers the certificate to it.

On the computer or phone, open a UDID site that supports Apple TV, such as udid.tv. It shows a short URL.
On the Apple TV, open Settings > General > Privacy & Security.
Highlight Share Apple TV Analytics and press Play/Pause on the remote.
Choose Add Profile and type the URL exactly, including https://.
Install the profile. The UDID appears on the site.
Send the UDID to your provider. You get back a .p12 certificate file, its password, and a .mobileprovision profile.

2. Pick a tool to install with

Tool	Sends to the TV from	Signs with
FlareStore app	iPhone, iPad, Mac	Apple TV certificate
ATVLoadly	Windows, Mac, Linux (Docker)	Apple TV certificate or Apple Account
Sideloadly	Mac	Apple Account
AppDB	Any browser	Apple TV certificate, with an install quota
Xcode	Mac	Paid developer account

With only an iPhone, use the FlareStore app. With a Windows PC, use ATVLoadly.

A free Apple Account also works with ATVLoadly and Sideloadly, under the same limits as on iPhone: apps expire after 7 days. ATVLoadly can refresh them automatically if it runs on an always-on computer. See free Apple Account.

3. Pair the Apple TV

Every tool except AppDB pairs the same way:

Put the TV and the device running the tool on the same Wi-Fi network.
On the Apple TV, open Settings > Remotes and Devices > Remote App and Devices. Stay on this screen.
Start pairing in the tool. The TV appears within about 45 seconds.
Enter the code shown on the TV into the tool.

If the TV does not appear, restart the tool and try again. On iPhone, the tool also needs Local Network permission. The FlareStore app then adds a VPN profile to reach the TV; you can turn it off after installing.

AppDB links the TV through the same Add Profile screen as step 1, using the profile URL it gives you.

4. Sign and install

Import the Apple TV certificate into the tool: the .p12 file, its password, and the .mobileprovision file. With an Apple Account, sign in instead.
Import the tvOS IPA.
Sign it with the Apple TV certificate, not your iPhone one.
Choose the paired Apple TV as the target and install.

If it fails

Symptom	Likely cause
The TV never shows up to pair	Different network, the TV left the Remote App and Devices screen, or Local Network permission is off
"Not supported on this device" error	The IPA is an iPhone build, not tvOS
No valid provisioning profile, or the install is refused	The certificate is not registered to this TV, or you signed with the iPhone certificate
Apps stop opening after 7 days	It was signed with a free Apple Account and needs refreshing

For anything else, use the error index. A revoked certificate stops TV apps too; the certificate checker confirms it.

Sources

FlareStore: Apple TV guide and Apple TV UDID grabber
ATVLoadly: project page
Sideloadly: official site
Signulous: registration page (tvOS Code Signing plan)
Apple Developer Forums: adding an Apple TV to a provisioning profile