billing

Capacitor plugin for in-app purchases (Android: Play Billing, iOS: StoreKit). The host app passes product id and type (INAPP / SUBS) on every call—the plugin is not tied to a specific SKU. (Native layers still apply fallback defaults if parameters are missing.)

The test-app/ folder contains a small Capacitor 8 sample app so you can try your own store SKUs via the UI, localStorage, .env.local (VITE_BILLING_TEST_*), or billingTestDefaults in test-app/capacitor.config.json (see test-app/README.md).

The web platform is not a real store; the plugin returns stub values there—see below.

iOS (Capacitor 8 + SPM)

From Capacitor 8 onward, the default iOS workflow uses Swift Package Manager. This plugin ships a root Package.swift so npx cap sync can link CapacitorBilling into CapApp-SPM. The native class conforms to CAPBridgedPlugin (same pattern as @capacitor/haptics and other first-party plugins).

Enable the In-App Purchase capability in Xcode for your app target.

Android setup

1. Register the plugin (legacy snippet)

Auto-discovery usually registers plugins; if you still use manual registration in MainActivity:

import de.carstenklaffke.billing.BillingPlugin;

this.init(savedInstanceState, new ArrayList<Class<? extends Plugin>>() {{
        add(BillingPlugin.class);
        }});

2. Gradle (Kotlin stdlib conflicts)

If your app hits duplicate Kotlin stdlib classes from Play Billing, add the following to your app’s android/build.gradle inside allprojects (or the equivalent in Gradle 8+), as needed:

allprojects {
    repositories {
        google()
        mavenCentral()
    }

    configurations.all {
        exclude group: 'org.jetbrains.kotlin', module: 'kotlin-stdlib-jdk7'
        exclude group: 'org.jetbrains.kotlin', module: 'kotlin-stdlib-jdk8'
    }
}

This plugin depends on Google Play Billing Library 9.x, which can pull older Kotlin stdlib artifacts. Excluding the deprecated jdk7/jdk8 artifacts avoids duplicate classes with newer Capacitor / Kotlin toolchains. Host apps that ship to Play must use a supported Billing Library; version 7 is blocked for new uploads after 31 August 2026.

Usage:

import {BillingPlugin} from "capacitor-billing";
import {Device} from "@capacitor/device";

BillingPlugin.querySkuDetails({ product: 'YOUR_SKU', type: 'INAPP' }).then((result: any) => {
    if (result) {
        if (result.value === "web") {
            setSkuInfos("web")
        } else {
            setSkuInfos({
                price: result.price,
                price_currency_code: result.price_currency_code,
                title: result.title,
                description: result.description
            });
        }
    } else {

    }
})

Device.getInfo().then((info: any) => {
    var product = "PRODUCT_NAME";
    BillingPlugin.launchBillingFlow({
        product: product,
        type: "SUBS"
    }).then((result: any) => {
        if (info.platform === "ios") {
            return BillingPlugin.finishTransaction({transactionId: result.storeKitTransactionID}).then((response: any) => {
                ...
                }
            )
        } else {
            return BillingPlugin.sendAck({purchaseToken: result.purchaseToken}).then((response: any) => {
                ...
                }
            )
        }
    })
})

Receipt validation

This plugin returns store tokens so your backend can verify the purchase. It does not call Apple or Google validation APIs itself (those need server secrets).

• iOS: launchBillingFlow resolves with purchaseToken (base64 App Store receipt) and storeKitTransactionID. Finish the StoreKit transaction with finishTransaction, then verify the receipt or the App Store Server API notification on your server.
• Android: launchBillingFlow resolves with Play’s purchase JSON, including purchaseToken. Acknowledge with sendAck, then verify the token with the Google Play Developer API on your server.