If you’re a mobile developer, and you’re currently on the fence over whether to integrate in-app advertising into your latest app, App Annie has some interesting data for you. In its predictions for 2019, App Annie suggested that 60 percent more apps will leverage in-app advertising over the next 12 months, and with good reason: “In 2018, mobile will account for 62 percent of global digital ad spend, representing $155 billion, up from 50 percent in 2017. In the US, mobile surpassed TV ad spend.” Last year, the group continued, the top downloaded apps “advertised across 35 percent more ad platforms and leveraged 170 percent more ad creatives than in 2017—meaning app marketers were employing more robust targeting and testing strategies.” Games on iOS, meanwhile, utilized “10 percent more ad platforms and 20 percent more creatives.” When used correctly, in other words, mobile advertising is apparently a goldmine for developers. Emphasis, of course, on “correctly.” Advertising isn’t the only thing slated to grow this year: overall consumer spend on mobile apps should surpass $122 billion, should App Annie prove correct. Much of that growth will be driven by China and emerging markets, with subscriptions playing a huge part of actual spend. Every year seems like a blockbuster one for the app economy, which is great news for mobile developers; the market for mobile apps clearly isn’t going to degrade anytime soon. However, all that activity creates issues of discoverability—it’s hard to make your app stand out when you’re competing against at least a hundred rivals that have similar functionality. And if you do succeed beyond your wildest dreams, chances are pretty good that some unscrupulous company will try to clone your functionality in short order. Fortunately, the app market is also creating new channels for monetization, which is great, provided you’re willing to put in the work and face the potential downsides. For instance, subscriptions are a wonderful way for developers to set up recurring payments from users, but require that the app introduce new features on a regular basis. In-app advertisements can ensure a stream of revenue proportional to the user base, but some users really don’t appreciate staring at interstitials or banners when they’re trying to play a game or type a note (especially if the advertising is presented in a particularly annoying way). Developers who want their apps to reach as wide an audience as possible should build for both iOS and Android, while remaining aware of how iOS apps tend to squeeze more money from users. Android has a larger install base globally, meaning your app could end up used by more people. (It’s too bad that Apple and Google are cracking down on the use of third-party cross-platform frameworks, given the added time it takes to build natively.) The bottom line here: Know your market. If you attempt to monetize in a way that your audience finds unsettling, they might drop your app for a competitor that doesn’t feature ads, for example. But if you know what they want, and build appropriately, you can succeed even in an ever-more-crowded environment.