Welcome

An overview of the Onside Payment SDK, designed for easy integration to help you monetize your apps with in-app purchases and subscriptions.

Monetize Your App with Ease

The Onside Payment SDK (OnsideKit) lets you integrate in-app purchases and subscriptions into your iOS app. It handles the entire payment flow — from product display to checkout — providing a secure experience for your users while keeping integration simple.

Currently supported payment methods: Apple Pay and bank cards. See Managing Payment Methods and Apple Pay.

New to OnsideKit? Start with the Quick Start for a minimal, end-to-end integration you can copy-paste, then come back here for the full guides.

Get Started

Follow these steps to integrate OnsideKit into your app:

Step	Guide	Description
1	Installation	Add OnsideKit to your project via Swift Package Manager, CocoaPods, or a manual framework install.
2	Initializing the SDK	Initialize OnsideKit, register your callback URL scheme, and forward incoming URLs for app-to-app login.
3	Authentication & User Account	Understand the login flows — explicit, implicit (on-demand), and session management.
4	Fetching Products	Fetch your product catalog, handle regional pricing, and display offerings to users.
5	Making a Purchase	Initiate purchases, process transactions, restore previous purchases, and validate on your backend.

Requirements

• iOS 16.0 or later

• Xcode 26 or later

• Distributed as a binary xcframework via Swift Package Manager and CocoaPods — see the Installation guide.

OnsideKit ships in two flavors: OnsideKit (the full SDK, with Apple Pay) and OnsideKitLite (the same SDK without the PassKit dependency, for apps that cannot include PassKit — Apple Pay is unavailable there). See OnsideKit vs OnsideKitLite.

Designed for a Seamless Transition

OnsideKit is intentionally modeled on Apple's native StoreKit framework. If your team has experience with StoreKit, integration will feel familiar — the same delegate patterns, a similar queue-based transaction flow, and comparable product-request APIs. See Migrating from StoreKit for a side-by-side mapping.

Key Features

• Familiar & easy integration: StoreKit-inspired API for a minimal learning curve.

• Purchases & subscriptions: one unified flow for consumables, non-consumables, and auto-renewable subscriptions.

• Apple Pay & bank cards: Apple Pay (full OnsideKit build) plus a built-in card-management UI.

• Clear responses & error handling: informative value types and a unified set of typed errors — see the Error Reference.

• Native, web & Unity: a native Swift API, a JavaScript bridge for WKWebView-based apps, and a Unity package.

• Test without a backend: develop and QA the purchase flow offline with Local Testing and a .storekit file.

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What You Can Do Now

You can start setting up your monetization strategy in the Onside Developer Console right away:

• Set up in-app purchases

• Configure subscriptions

Related topics

These are the next docs most teams need after the core integration:

• The Onside Delegate — theming, host window scene, login routing, and region hints

• Attribution — install-attribution metadata

• Building funnels with event tracking — track actions with Onside.track

• Purchase Validation — server-side verification with the Merchant API

• OnsideKit Example App — a working reference project

Need More Help?

Resource	Description	Link
Monetization Overview	All monetization options available on Onside	Go to Monetization Overview
Contact Support	Questions about the SDK? Our team is here to help.	Email Us
Main Help Section	Common questions about developing for Onside	Visit Help Section