In-app advertising continues to be one of the most effective ways to monetize mobile apps. In this guide, we’ll break down high-performing ad formats, the most reliable traffic sources, and how to make them work for your app’s growth and revenue.

In-app advertising has quickly become one of the most effective ways to promote and monetize mobile apps. As people spend more time in apps—on average over 100 minutes daily—it’s no surprise that brands are following their attention. And they’re not just testing the waters. Global in-app ad spending is rising, with per-person spending expected to hit nearly $50 by 2025.

In the U.S., where digital dominates the ad market, total ad spending is forecasted to reach a massive $456 billion next year. With in-app ads performing significantly better than the mobile web—boasting an average CTR of 0.56% compared to just 0.23%—it’s clear why marketers are turning to this channel. All this makes in-app advertising a solid revenue stream and a key growth component for mobile app developers.

So, what’s in-app advertising?

By definition, it means showing ads directly inside mobile apps. These ads come in a variety of formats and aim to engage users without interrupting the app experience. For developers and marketers, it offers a powerful way to monetize apps and drive user acquisition—especially as mobile usage keeps rising.

In-app advertising operates through ad networks that connect advertisers with mobile app developers. When an ad appears inside an app and a user sees or interacts with it—like tapping or watching a video—that action counts as in-app traffic. If the user installs the promoted app, completes a purchase, or performs another desired action, it’s considered a conversion. Developers typically earn revenue based on impressions (CPM), clicks (CPC), installs (CPI), or specific in-app actions (CPA), depending on the campaign goals and pricing model.

Now that we covered how in-app advertising works, we can look at the most widely used ad formats closer. Here, it's worth noting that each format serves a different purpose and suits different user behaviors and app categories.

These full-screen ads appear during natural pauses or transitions in the app—like between game levels or while loading new content. Because they take up the entire screen, interstitials are hard to miss and often used for high-impact campaigns. They typically feature video or playable creatives, offering a more immersive experience than static ads. However, you might want to be careful about timing. Poor placement can frustrate users, while smart timing can drive strong results without harming retention.

Banner ads are rectangular units placed at the top or bottom of the screen, often remaining visible while users interact with the app. It's a classic, simple ad format. Being less attention-grabbing than full-screen formats, banners are cost-effective and easy to implement. Standard sizes for banner ads are 320×50 or 300×50. This ad format is most effective in apps with long session times, where subtle ad exposure can add up without harming user experience.

Such ads usually match the app’s content and design, making them look like part of the user experience. Because of their non-ad look, native ads often enjoy higher engagement and lower bounce rates. Social and content-driven apps frequently rely on this format—for example, ads resembling user posts in a feed. There's a challenge for marketers, though—keeping the message stand out and maintaining a natural appearance.

This format implies people watch an ad in exchange for something of value—like in-game currency, extra lives, or premium features. It is pretty much similar in concept to incentivized traffic.​ Rewarded ads are frequent in mobile games and apps with freemium models because they turn advertising into a positive user experience. Since users opt in, these ads typically generate higher completion rates and positive sentiment.

Playable ads give users a short, hands-on preview of the promoted app—usually a mini-version of a game or interactive demo. They are often used in user acquisition campaigns, especially for gaming apps. By letting users try before they install, playables help reduce churn and attract more qualified users. Such ads are typically shown in full-screen mode and rely on engaging, responsive design to hook users quickly.

Video ads can come in multiple formats—interstitials, rewarded, native, or banners—and can deliver a more dynamic and emotionally engaging message. In-app video ads are typically split into in-stream (shown within video content) and out-stream (placed independently, like between app actions). For campaigns aiming to boost brand awareness or tell a story, video remains one of the most effective tools—especially when optimized for mobile viewing behavior.

Now, let's explore how these formats perform in terms of user engagement and revenue, and how you can choose the best option for your app.

Several studies have examined the effectiveness of these formats, helping us understand which ones provide the best balance of user experience and monetization potential.

Appodeal found that rewarded video ads consistently outperform others in terms of effective cost per mille (eCPM), followed by interstitial ads. Banners, despite having the highest number of views, significantly lag behind in terms of monetization capability.

It’s worth mentioning that banners, having the highest view count, share the top position in terms of monetization capability with interstitial interactive ads, despite the latter having 11 times fewer views.

According to AdColony’s revenue source statistics, video ads make up a significant portion of publishers' revenue, second only to in-app purchases.

As for the best user experience, rewarded videos take the lead.

Considering the above, full-screen, video, and rewarded ads can drive revenue and help build stronger user engagement. Tapjoy data shows that the more users interact with these formats during their first week in the app, the more likely they are to stick around. In fact, users who watched at least one rewarded video were 300% more likely to return within 30 days.

In short, the most effective in-app ad formats—rewarded video, video, and interstitials—boost monetization, support retention, and increase satisfaction. Here, the key is thoughtful integration. When ads are built into the user journey in a way that feels natural, they enhance the experience instead of interrupting it—turning ad placements into added value, not just revenue streams.

With your strategy in place, it’s time to explore the platforms that can bring it to life. Below are six trusted ad networks—each offering a unique blend of formats, pricing models, and campaign tools—plus a bonus App Store feature to help you boost visibility and keep users engaged.

Unity Ads allows you to promote and monetize mobile apps through interstitial video ads, with a minimum deposit of $1,000. The platform supports various ad formats, including standard, interactive, and rewarded videos. You can choose to pay either per app install or per video view. Unity’s machine learning system automatically identifies high-value users and targets them with relevant ads.

AppLovin supports both CPC and CPM bidding models, with a minimum payment of $100. The platform offers built-in creative tools and specializes in native ad formats. Campaigns can be easily optimized and managed directly through the dashboard.

Vungle specializes in mobile video advertising and supports both CPI and CPM models. You can upload your own video creatives or produce ads through Vungle’s in-house studio. The platform includes advanced analytics and A/B testing capabilities, allowing you to segment audiences, track campaign performance, and monitor impressions, installs, and revenue through a detailed dashboard.

ironSource is an official partner of AppsFlyer and offers a full suite of tools for app monetization, user engagement, and performance analytics. Ad format options include native, interstitial, banner, and video ads. It is widely used in the mobile gaming space and supports deep integration with popular engines like Unity.

Minimob is a performance-based ad network that supports CPC, CPM, and CPI models. The platform includes its own SDK and offers built-in optimization algorithms for campaign management. One of its key strengths is adapting ad delivery based on user behavior to show more relevant content. Supported formats include interactive and rewarded videos, banners, and interstitials.

Bigo Ads is a global mobile marketing platform with ad placements available in popular apps such as the short video platform Likee and the messaging app IMO. It also features its own media network. The platform is known for its large youth-focused audience across regions like Asia, the Middle East, and Eastern Europe. Bigo Ads supports both dynamic video ads and static creatives, and it features lenient moderation, making it accessible for various types of campaigns.

In-app events are a native App Store promotional tool designed to highlight key happenings within your app—such as updates, challenges, flash mobs, sales, and themed online activities. Developers can create event cards that include both text and rich media content.

These event creatives appear in your App Store listing, search results, featured recommendations, and other placements—often as banners. Users can set reminders directly from the event card and receive notifications when the event starts. This format helps increase awareness, drive engagement and installs, build community around your app, and demonstrate that your app is actively maintained and evolving.

Long story short, in-app advertising can be a strategic lever for mobile app growth. It helps generate income without interrupting user experience—especially in the case of native and rewarded formats. Still, to make the most of in-app advertising, one needs to approach it with the app’s niche, audience behavior, and monetization goals in mind when choosing traffic sources and ad formats.

Monetization is just one part of the equation. For long-term growth, your app also needs visibility, installs, and user trust.