Do you need the HomeKit setup code again after pairing?

In normal use, no. Once an accessory is paired to your home it stays paired. It survives the accessory rebooting, your router restarting, iOS updates, Home app updates, and moving to a new iPhone. You can go years without thinking about the code.

Keep it anyway. The times you need it again are the times you least want to be hunting for it.

When the code comes back

• You factory reset the accessory, usually to fix one that has gone unresponsive or is stuck offline. A reset clears the pairing, so adding the device back needs the original code. It does not generate a new one.
• You move it to a different home or a different Apple account. Selling a house, shifting a device to a holiday flat, handing it to a family member. Removing an accessory from one home wipes its pairing, and the next home asks for the code.
• You sell or give the device away. The new owner pairs it fresh with that same code. Remove it from your home first, then pass on the code or a photo of the label.
• You switch it between the maker’s app and Apple Home. Some accessories need a reset and re-pair to change which app owns them.
• An accessory drops off and will not come back. Half the troubleshooting guides for a stubborn device end with “remove it and add it again”, which means the code.
• You rebuild your home. Rare, but HomeKit databases do occasionally get into a state where the fix is removing accessories and re-adding them.

One case looks like it needs the code but does not: adding a Matter accessory to a second platform, such as Alexa or Google Home, alongside Apple. That uses a temporary code the Home app generates for you, not the number on the sticker.

Changing your Wi-Fi network name or password is a grey area. It can force you to re-onboard some Wi-Fi accessories, and a few of those routes run through a factory reset. Thread and Bluetooth accessories are not affected.

When you do not need it

• Rebooting the accessory, the hub, or your phone
• Updating iOS, or the Home app
• Setting up a new iPhone or iPad
• Adding another person to your home. They use your invitation, not the code

The catch

Apple Home never shows the setup code once an accessory is added. There is no “view code” option, and it is not handed to third-party apps either. So if one of the situations above turns up and the sticker is gone, you are recovering the number the hard way.

The fix is upstream and takes a minute: back up the code the day each accessory goes in.