App-owned TOML metafield definitions: what happens after uninstall/reinstall?

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1

Hi,

I have a question about app-owned metafield definitions declared via shopify.app.toml (no API-created definitions, no app-data metafields). The app is installed on a specific store via app distribution link (not published on the App Store).

If I uninstall and reinstall the same app (same client_id) on the store:

  • Are metafield values lost? Or do they persist and get re-associated with the new installation?
  • Do definitions get a new App ID namespace? (e.g. app--OLD_ID → app--NEW_ID) And if so, does the data follow?

Additionally: if I have metafields that need to be referenced by external integrations (theme Liquid, third-party tools), is it better to declare them as app-owned (via TOML with $app namespace) or as merchant-owned (e.g. custom namespace) to avoid dependency on the app lifecycle?

Thanks for any clarification!

2

Hey @Max86 :waving_hand: thanks for reaching out.

I tested this today using a TOML-defined app-owned product metafield and Admin GraphQL API version 2026-07.

After uninstalling and reinstalling the same app, this is what I observed:

  • The App GID and app–{app_id} namespace were unchanged.
  • The AppInstallation GID changed.
  • The metafield definition GID changed.
  • The metafield GID and stored value were unchanged.
  • The definition returned with a new GID after reinstall. The retained metafield’s nested definition.id changed to that same new GID.

The public metafield-definition documentation doesn’t currently specify uninstall/reinstall behaviour, so I’m going to dig into this deeper as well:

If these metafields or metaobjects need to be accessible by another app, Shopify’s documentation says they must use a custom namespace rather than the owning app’s reserved namespace: Public access for app owned metafields and metaobjects is now disabled - Shopify developer changelog

I’ll follow up here once I more information to share and I hope this helps point you in the right direction for now!