Most studios think plugging in an SDK is enough.
You integrate the networks, ads start showing, revenue starts flowing. Simple, right?
Not quite. Felix Braberg—ad monetization consultant, former head of ad mon at Tetris and East Side Games, and manager of over $500M in ad earnings throughout his career—breaks down exactly where studios leave money on the table.
Here's what every mobile developer needs to know before (and after) going live with ads.
The Four Metrics That Actually Matter
Before anything else, get these four metrics tattooed in your brain.
eCPM (Effective Cost Per Mille) This is how much networks pay you per 1,000 impressions. Everyone obsesses over it. But on its own, it tells you almost nothing.
Fill Rate The percentage of your impression opportunities that are actually sold to networks. You could have 100,000 impression opportunities—but a 2% fill rate means you're leaving 98% of potential revenue on the table.
"A good fill rate on video in mobile should be about 98%. There's no excuse in 2025 why you shouldn't be hitting that."
Ad Revenue = eCPM × Fill Rate This is the number that actually matters. A lower eCPM with a higher fill rate will almost always beat a higher eCPM with poor fill. Don't let networks dazzle you with eCPM numbers in isolation.
Ad ARPU (Ad Revenue Per Daily Active User) This is the one metric that gives you a clear line of sight on whether your monetization is actually working—and how it's being affected by your UA strategy. Always look at ad revenue on a per-user level.
"When you talk to ad networks, always talk about ad ARPU. If you only talk about eCPM, they'll know you don't fully understand the space."
How Networks Calculate eCPM (And Why Your Numbers Will Drop)
Every network uses a different algorithm, but a few factors are universal: app install history, recent bidding performance, geolocation, and—critically—how many impressions you've already shown to a given user in their session.
Here's the part most studios miss: eCPMs are usually highest when you first launch.
Networks haven't had time to fine-tune their campaigns. There's limited historical data. So they bid broadly. Over time, as they optimize, eCPMs settle into their "real" range.
Don't panic when this happens. It's normal.
The Recency Model: Why More Impressions ≠ More Revenue
All networks operate on what's called a recency model.
Networks are willing to pay more for the first impression shown to a user than the fifth. Each subsequent ad shown in a session is worth less than the one before it—because user attention degrades.
On full-screen video (interstitials and rewarded), the per-unit price tends to drop significantly after the fifth impression.
"I've worked with clients where we increased impressions per daily active user and saw almost no revenue boost—because the price curve had already flattened out."
The practical takeaway: Don't blindly show more ads. Always look at the per-unit value of impressions, and ask whether that seventh or eighth interstitial is actually adding revenue—or just accelerating churn.
SDK Updates: Never Be the First Studio to Upgrade
When you add new networks to your mediation platform, watch your ANR (App Not Responding) rate and crash rate carefully—especially on Android.
Android requires studios to stay below a 0.2–0.3% crash/ANR threshold. Exceed that, and you'll lose organic traffic. Google Play rewards stable apps.
"Network sales teams are incentivized to get you on new SDK builds as fast as possible. Don't fall for it."
The playbook: Wait 2–3 weeks after a new SDK drops. Do a quick search for crash complaints from other studios. If it's clean, update. If not, hold off.
Ad Formats Are Getting Longer—And That's Your Problem
Over the last six years, mobile ads have gotten more aggressive. Rewarded ads are no longer 30 seconds with a clean close. Interstitials are harder to skip. End cards are harder to dismiss.
Why? Networks earn on conversions. Harder-to-close ads = more misclicks = more installs for their UA campaigns = more money for them.
But for you as a publisher, this is a retention problem. Long, annoying ads accelerate churn.
"When clients actually removed aggressive end card templates, they saw lower churn rates."
What to negotiate with every new network:
Format | Recommended Setting |
|---|---|
Rewarded Video | 30 seconds max + 5 seconds to close |
Interstitial | 5 seconds to close |
Clicks to Close | 3 clicks maximum |
Set these expectations before you sign anything.
Ad Networks vs. Exchanges: Know the Difference
Ad Networks have a direct SDK integration with publishers. When you plug in a network, you're getting their direct demand—plus whatever reseller demand they've agreed to route through their SDK.
Here's what most studios don't realize: for most ad networks, only 30–60% of demand is actually direct. The rest comes from resellers paying a cut (often 30%) to access your inventory through the network's infrastructure.
This is why keeping your app-ads.txt file up to date is critical. Without it, you're blocking legitimate reseller demand and losing revenue you don't even know you're missing.
Exchanges (like DT Exchange or Bid Machine) are different. They have no direct demand of their own—they're purely resellers connecting DSPs to your inventory.
"The difference matters when you're thinking about where your revenue actually comes from—and how to protect it."
Why Mediation Platforms Are Non-Negotiable
If you're currently running ads through a single network, you're leaving serious money behind.
Mediation platforms create a competitive marketplace for your inventory. Instead of one buyer, you get dozens bidding simultaneously for every impression. The result?
"In my experience, adding a mediation platform typically doubles your ad revenue. You go from $100/day to $200/day, just from introducing real competition."
The main platforms to evaluate: AdMob, AppLovin MAX, and Unity LevelPlay. Start with 3–4 networks. Once you're hitting $1,000–$1,200/day in ad revenue, expand from there.
Where to Start
Here's the practical sequence for studios just getting into ad monetization:
Pick a mediation platform — AdMob, MAX, or LevelPlay
Start with 3–4 networks — prioritize the biggest names first
Set ad format standards upfront — negotiate close times before going live
Watch ANRs and crashes on every SDK update
Track ad ARPU, not just eCPM — it's the only metric that tells the full story
Keep your app-ads.txt updated — don't lose reseller revenue unnecessarily
Monitor the recency curve — more impressions is not always more revenue
The fundamentals aren't glamorous. But getting them right is what separates studios that scale their ad revenue from those that leave half of it behind.
Based on Felix Braberg's mobile ad monetization episode from the Two and a Half Gamers podcast.