Two parents, one ledger, nobody pays twice

The problem

Why do two parents end up running two separate versions of the truth?

In most families, the phone that has the app is the phone that runs the household. The other parent gets updates secondhand, over text, after the fact. That works until it does not: an approval waits because the parent with the app is in a meeting, or a reward gets approved twice because nobody told the second parent it already happened.

Family Sharing already solves paying for the app once across a household. It does not solve one parent working from a copy of the truth that is a day out of date, or a child asking the parent who happens to be around rather than the one who actually said yes.

The underlying issue is not communication between two adults who get on fine. It is that most household software was built around one login, and a second parent bolted onto that design ends up as a viewer at best, or a second, disconnected copy of the household at worst. Either way, somebody is working from stale information without knowing it.

The invitation

How does a co-parent actually get into the same household?

The mechanism is CKShare, Apple's own sharing framework built into iCloud. The parent who set up the household sends an invitation, the other parent accepts it on their own device, and from that point both of them are looking at the same record: the same kids, the same tasks, the same reward shop, and the same ledger of every credit that has ever moved.

Nothing is copied and nothing waits for a sync window. It is one household with two doors into it, so an approval typed on one phone appears on the other one straight away, without either parent doing anything to make that happen.

• The invited co-parent never takes a paid seat and never needs a subscription of their own.
• Both parents can approve tasks, adjust credits by hand, and see the full history with the reason behind every entry.
• A child linked to the household can accept the same kind of invitation and self link their own device, a mechanism added in version 1.0.3.

This is part of why Pro pricing is set per household rather than per parent: the co-parent invitation is something a subscription already covers, not an upsell sitting on top of it.

Each parent's own lock

Do both parents share one PIN, or does each get their own?

Joining the same household does not mean sharing one gate into it. Every parent action, on either device, sits behind that device's own Face ID or Touch ID, with a parent-set PIN as the fallback if biometrics are unavailable. The PIN is a salted, stretched hash stored only in that device's own Keychain, never sent anywhere and never shared between the two parents' phones.

That has a practical effect on the co-parent setup specifically: there is no shared secret to agree on, hand over, or forget to update after a phone gets replaced. Each parent unlocks their own device their own way, and both land on the same household once they are through.

Where the data actually lives

Does inviting a co-parent send the household to a new server?

No. There is no account to create and no server run by the developer that either parent's data passes through. The household lives in the family's own iCloud, and CKShare is Apple's own mechanism for extending access to a second Apple Account within that same iCloud data, not a copy sent somewhere new. There are zero third-party SDKs in the app, and the App Store's own privacy label for it reads Data Not Collected.

For two parents deciding whether to link their households, that answers the question underneath the technical one: nobody except the two of them, and Apple's own iCloud infrastructure carrying it between their devices, ever sees the invitation or what it shares.

Two households, one Apple Account

What if the second parent already runs a household of their own?

Being invited as a co-parent does not use anything up, and it does not stop that parent from also owning a completely separate household, for children who are not part of the shared one. That is a different feature: two households under one Apple Account covers the case, most often separated parents each running their own tasks and rewards for the time a child is actually with them.

Being a co-parent inside one household and an owner of another are not in conflict. Nothing from one crosses into the other, and joining a household by invitation, the ordinary co-parent case this post is about, never needs a paid seat in either version of the app.

Notifications

Why does only one parent get told when a task is finished?

Notifications in Reward Study are shaped by what a device actually needs to know, not broadcast to every device attached to the household. A parent's device is told when a child finishes a task or asks to spend credits, because that is the moment a parent has something to decide. A device is never notified of its own action: the phone that just approved something does not also buzz a moment later to tell you that you approved it.

With two parents sharing a household, both are told about a child's action, and neither is told about the other's approval as if it were news. The ledger already records who approved what and when, with the reason attached, so if you want to know what your co-parent did while you were out, the history answers it without a running commentary of notifications trying to do the same job worse.

The same rule applies to a child's own device or Kid Mode session: the child is told when something is approved, rejected with a note, or hand-adjusted with a reason, and told nothing at all about actions on the parents' side that never involved them. A notification exists to tell somebody something they did not already know, not to announce every event in the household to every screen that happens to be signed in.