OpenIAP is a standardized, meta‑backed specification and set of SDKs that unify in‑app purchase handling across all major platforms (iOS/macOS, Android, Expo, React‑Native, Flutter, Kotlin Multiplatform, Godot, etc.). It provides a GraphQL‑based spec plus ready‑to‑use libraries and documentation so developers can implement purchases with a single, consistent API instead of dealing with platform‑specific quirks. The project targets mobile, web, and game developers who need a cross‑platform IAP solution.