Add In-App Purchases: Cross-Platform App Boilerplate

Are you ready to unlock new revenue streams for your app—on every platform? The opportunity is huge. But the technical hurdles are real. In this guide, you'll learn how to add in-app purchases (IAP) to web, iOS, and Android with a single codebase. You'll also discover the hidden challenges, and how the MoneyMouth boilerplate can save you months of work and help you earn sooner.

Why In-App Purchases Matter

In-app purchases are one of the fastest ways to monetize your app. Whether you're building a SaaS product, a mobile game, or a productivity tool, IAP lets you:

• Sell subscriptions or one-time features
• Offer premium content or upgrades
• Unlock new features for your users
• Grow your revenue without ads

But here's the catch: every platform handles payments differently. And getting it right everywhere is much harder than it looks.

1. The Real Challenge: Payments Everywhere

Adding in-app purchases isn't just about showing a paywall. Each platform has its own payment APIs, compliance rules, and user experience quirks. Let's break it down:

Web: Stripe Is King, But Not Simple

• Stripe is the gold standard for web payments.
• You need to handle subscriptions, one-time purchases, and webhooks for fulfillment.
• Security is critical. You must protect user data and prevent fraud.
• You need to manage failed payments, refunds, and renewals.
• See the ultimate checklist

iOS: StoreKit and Apple's Strict Rules

• StoreKit powers in-app purchases and subscriptions on iOS.
• Apple's review process is strict. Missing a single compliance step can mean rejection.
• Edge cases abound: what if a user cancels a subscription? What if a payment fails?
• You must use Apple's APIs for digital goods, or risk being removed from the App Store.
• Avoid common pitfalls

Android: Google Play Billing

• Google Play Billing is required for in-app purchases on Android.
• Google has its own flows and compliance requirements.
• You need to handle purchase validation, refunds, and subscription renewals.
• Testing can be tricky, especially for edge cases.

Unified Experience: What Users Expect

• Users expect a seamless, consistent purchase flow—no matter the platform.
• If your payment experience feels clunky or inconsistent, users may abandon their purchase.
• Why a unified tech stack matters

2. Why Most Teams Get Stuck

Even experienced developers underestimate the complexity of cross-platform payments. Here's what usually happens:

• Weeks lost integrating and debugging payments for each platform.
• App store rejections for missing compliance steps or using the wrong APIs. (Read the guide)
• Edge cases like failed payments, refunds, and subscription renewals.
• Testing headaches—mocking purchases and simulating failures across platforms is tough. (How to test cross-platform apps)
• Maintenance overload—every update to a payment API means more work for your team.

Real-World Example: The DIY Trap

Imagine you're a small team building a productivity app. You want to launch on web, iOS, and Android. You start by wiring up Stripe for the web. It takes a week. Then you tackle StoreKit for iOS. Suddenly, you're reading Apple's 100-page compliance guide. Android is next, and Google's documentation is different again. Weeks turn into months. You're still not live.

3. The MoneyMouth Boilerplate: Payments, Pre-Wired

MoneyMouth is built to solve these exact problems for SaaS teams and indie devs. Here's how it helps you launch faster and earn sooner:

All Major Payment APIs, Pre-Integrated

• Stripe, StoreKit, Google Play Billing: All pre-integrated, with a unified purchase flow and robust error handling.
• No need to write custom code for each platform. Focus on your app, not on payment plumbing.

Subscriptions & One-Time Purchases

• Support for both models, with webhooks and server-side validation.
• Easily offer monthly, yearly, or lifetime access.

App Store Compliance, Built-In

• Built-in flows to help you pass review on the first try.
• Automatic handling of edge cases and compliance requirements.
• See what makes a SaaS app 'App Store Ready'

Testing Utilities

• Simulate purchases, failures, and refunds across all platforms.
• Test your flows before you go live, and catch bugs early.

Analytics and Notifications

• Track revenue and user behavior out of the box. (How to track analytics everywhere)
• Send purchase confirmations and renewal reminders automatically. (How to build a scalable notification system)

Local-First & Offline Support

• Purchases sync when users go back online.
• Users can buy and use features even with spotty internet.
• Why local-first matters

4. Save Months—Monetize from Day One

MoneyMouth was built to save you the 6+ months it takes to wire up payments yourself. You get a production-ready foundation, so you can focus on your app's unique value—not on plumbing. (See the true cost of DIY infrastructure)

How Much Time Can You Save?

• Web payments: Save 2-3 weeks
• iOS payments: Save 4-6 weeks
• Android payments: Save 3-4 weeks
• Testing and compliance: Save 2-3 weeks
• Total: Save 2-4 months (or more!)

5. Real-World Example: ProgressMade.ai

Apps like ProgressMade.ai launched on all platforms in record time using this boilerplate, monetizing from day one. (See the case study)

Their Story

ProgressMade.ai is a SaaS app that helps users track their goals and habits. The team wanted to launch on web, iOS, and Android—all at once. They used MoneyMouth to handle payments everywhere. Instead of spending months on payment integration, they focused on building features their users love. They launched in weeks, not months, and started earning revenue from day one.

6. Actionable Checklist: How to Add In-App Purchases Everywhere

Want to add in-app purchases to your app? Here's a step-by-step checklist:

1. Define your pricing model: Subscriptions, one-time purchases, or both?
2. Choose your platforms: Web, iOS, Android, or all three?
3. Pick your payment providers: Stripe (web), StoreKit (iOS), Google Play Billing (Android)
4. Plan your user experience: Make the purchase flow seamless and consistent.
5. Handle compliance: Follow App Store and Google Play rules for digital goods.
6. Test everything: Simulate purchases, failures, and refunds on every platform.
7. Track analytics: Monitor revenue and user behavior.
8. Send notifications: Confirm purchases and remind users about renewals.
9. Support offline use: Make sure purchases sync when users go back online.
10. Launch and iterate: Go live, gather feedback, and improve your flows.

7. Launch Faster, Earn Sooner

With MoneyMouth, you can:

• Add in-app purchases to web, iOS, and Android in days, not months.
• Monetize with subscriptions and one-time purchases everywhere.
• Deliver a seamless, high-performance experience on every platform.
• Get peace of mind with a full refund guarantee if your app isn't accepted by the app stores.

8. Frequently Asked Questions

Q: Can I use MoneyMouth for an existing app? A: Yes! You can integrate MoneyMouth into an existing codebase or use it as a starting point for a new project.

Q: What if I only want to support one platform? A: MoneyMouth works for single-platform apps too. But you'll be ready to expand to more platforms when you're ready.

Q: Is it secure? A: Yes. MoneyMouth uses best practices for payment security and data protection.

Q: What support is available? A: You get documentation, sample projects, and community support. Paid support is also available.

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Ready to monetize everywhere? Check out the MoneyMouth boilerplate and add in-app purchases to your app—fast. Don't let payments slow you down. Launch faster, earn sooner, and focus on what makes your app great.