Homegrown share lists miss the destinations people already use

What it is

A custom share list is a row of icons the product draws itself (a messenger, a microblog, mail) in place of the system sheet. The names come from launch-time partnerships and market averages, not from the receivers this person actually uses on this device. The misses are often the ones that matter: an internal company app, a regional messenger, a reader installed last week, Save to Files, AirDrop. This entry is about who appears in the list. It is not about the sheet's role as an exit, and not about whether the payload is a format the receiver can open.

Why it happens

The sandbox forbids a sender from reading the full install graph, so a homemade list is a compile-time constant or a remote allowlist. Sorted by market average, it is wrong for a single device: a pinned target is absent, a listed target is not installed and the tap dumps into a store. The homemade row and the system sheet also fork: the same messenger is already pinned in the sheet, yet the in-app icon opens a different share kit, with a different thread list, file support, and login. Two "share to the same app" actions are not one operation. The list also ages. A newly installed receiver appears in the system sheet as soon as it registers; it appears in the homemade row only after a release.

Where it stops holding

When regulation or brand contracts force a closed set of destinations (government filing, licensed content that may only go to certified platforms), a fixed list is a constraint, not an omission. Receivers that still have no share extension can only be reached by an in-app protocol; that does not justify replacing every destination. If a very widely preinstalled app cannot exercise its full capability through the sheet (plain text in a composer, no order card), offer an extra in-app deep link beside the sheet rather than swapping the sheet for a wall of icons.

Applying it

• Call the system sheet by default. If one or two partner destinations must be featured, add them as shortcuts around the sheet, not as a replacement for the whole set.
• Do not show an icon for an app that is not installed and reveal the store only on tap. An empty slot is the product's guess covering the device's real state.
• Verify with a colleague outside the target persona: list the three apps they actually use to receive files from the home screen, then open the product's share entry and count how many of those three are reachable in one tap. Each miss is an omission of the homemade list.

Related

• Within the group: K1.07.1 The system share sheet is the standard exit to other apps · K1.07.3 Share payload format determines whether the receiver can use it
• Adjacent: K2.05 Cross-application drag and drop · K2.10 Clipboard and system services
• Search terms: custom share list · share sheet · share extension