Architecture Notes
4.1 · Monetization

App Monetization Design — Choose a Revenue Model from Your Cost Structure

2026.07.07~4 min

00Overview

Tools

  • AdMobIn-app ads (4.1.1)Free
  • App Store billingIAP / subscriptions15–30% of revenue
  • Apple Developer ProgramPrerequisite for billing (see 4)$99/yr

01Why

App monetization is not about making money. It is the machinery that keeps a product from dying.

When development stops, users lose the value — and the trust goes with it. So the product gets a mechanism for staying alive, designed in from the start. Take the "survival strategy" of 4 Monetization and focus it down onto one app, and this is what it looks like.

02How

The thinking runs in three steps.

① Understand the cost structure. Servers, AI APIs, licenses, spec churn, maintenance. Running cost is not just the monthly invoice — every dependency on an external service is a future maintenance cost in disguise. First, cut dependencies.

② Tie costs to revenue. AI usage → subscription. Server usage → recurring billing. Fully offline → one-time purchase. Free and wide → ads. You don't pick a revenue model because it earns; you pick it because it matches the cost structure.

③ Design the emotional side. One cent is enough at first. What matters early isn't profit but the felt proof that someone is using it. So keep both ads and billing restrained at the start, and put being used first. Grow the ads and the billing after the users arrive.

The concrete ad placement — where, and how sparingly — is in 4.1.1 AdMob.

03What

There is no single correct revenue model.
Match it, honestly, to your costs and your purpose.

Paid app, in-app purchase, subscription, AdMob. None of them is the right answer. The one that fits your cost structure and your product's purpose is the answer — that is what monetization design that keeps an app alive means.