As app developers, we want to make sure we are making as much money as possible from our in-app advertising. Unfortunately it’s not as simple as building an amazing app, carefully thinking about your ad strategy, and choosing a good ad network with a nice high eCPM. Why? Because there is more to consider than just eCPM when measuring an ad networks performance. By only using a single ad network I can guarantee you are leaving money on the table.

The Problem – Less than 100% Fill Rates

Before we get to the good stuff, let me quickly explain the concept of ‘Fill Rates’ and why it can be a problem. If you already know what fill rate is, feel free to skip to ‘What is Ad Mediation’.

So, what is ‘Fill Rate’?

When your app needs to show an ad, it sends a request to the ad network asking for something to show. The ad network has an inventory of ads from all different advertisers ready to be displayed.

But it’s not as simple as grabbing any ad from the inventory and serving it up. Advertisers may specify that they only want their ads shown in specific countries, or on certain devices etc. They also specify a daily budget, meaning once that budget is reached, those ads won’t be served up any more. Add that to the fact that there are millions of apps out there requesting ads, and sometimes there just isn’t any suitable ad inventory available.

That means there are no ads for the network to pass back. Aka. There is no ad ‘fill’.

What happens next? Nothing. If there is no inventory, no ad is shown in your app. And on top of this, no ad impression is recorded.

The percentage of requests that return an actual ad is known as the Fill Rate. For example, if your app asks for an ad 100 times, but the network only has enough inventory to pass an ad back 80 of those times, the fill rate is 80%.


Fill Rates and eCPM

Think about this if you are measuring the performance of an ad network based on eCPM (effective cost per 1000 impressions). If no impression is recorded when there is no fill, it doesn’t effect the eCPM.

I’ll put this into numbers for you.

Let’s say you’re using an ad network that boasts an eCPM of $2. You would expect that for every 1000 times an ad is supposed to be displayed in your app you should earn $2.

But what if this network has a fill rate of 60%? That means that out of 1000 requests, only 600 ads actually get displayed. Instead of $2, you would only receive $1.20.

That’s a massive difference! And here’s the kicker: There’s a very good chance that network won’t provide fill rate as a metric for you to see. So you won’t even know if you’re missing out on ad impressions!

This is where Ad Mediation comes to the rescue.


What is Ad Mediation, and how can it increase my revenue?

Now that you understand why using a single ad network for any given ad placement can be a problem, let’s talk about a solution.

Ad mediation allows you to configure a number of different ad networks and rank them in order of preference.

When it is time to display an ad, the mediation service will send a request to the highest-ranking ad network in your list. If that network cannot provide an ad, it sends a request to the next network in the list. This continues down the list until an ad is served. It means that even if one ad network doesn’t have any inventory available it’s not a problem. The mediation service will just go get an ad from another network.

To maximise your revenue, you should generally give the highest eCPM networks top priority. That way the mediation service will attempt to serve these high performing ads first. Lower performing ads are then shown only if the others don’t have inventory.


Why Should You Implement an Ad Mediation Solution?

This question has probably already answered itself by now, but I want to give you a summary of the benefits and cover a few other benefits of using mediation for your mobile advertising.

  • We know that ad mediation overcomes the problem of less than 100% fill rates from mobile ad networks. You are no longer relying on just one ad network to provide ad fill for a given placement.
  • 100% ad fill means you are not leaving revenue on the table. Rather than missing out on potential revenue when a particular ad network doesn’t have any inventory to show, you are assured that an ad will be served by another network.
  • It gives you data that most ad networks won’t, Fill Rate. Most mediation services I’ve worked with will give you a comprehensive summary of information about your ad publishing campaign. Among other things, they will tell you how many times an ad was requested from each network and how often those requests were filled. They will usually even do the calculation for you and give you the fill rate as a percentage right on the dashboard.
  • You can see how each ad network is performing and make changes from your mediation provider’s dashboard without having to update your app. If you see one network providing much higher eCPM’s than the others, all it takes is a few clicks to bump up it up to the top ranking preference. From then on, the mediation service will always attempt to use that ad network first.
  • Fewer SDK’s to manage. Depending on the mediation solution that you choose to use, you may be able to significantly reduce the number of SDK’s in your app. Instead of one SDK per ad network, you may only need one for your mediation platform. Having to manage fewer SDK’s can only be a good thing.


How Can You Do It?

Another great thing about ad mediation is that it is becoming very easy for indie developers to implement. There really is no reason not to use it.

Use An Ad Mediation Platform

The easiest way to implement ad mediation into your app is to use a mediation platform. There are lots of services out there that you can use. A few popular ones that I have tried are:

I’d recommend checking out a few and finding one that covers all of the mobile ad networks that you would like to use.

Build a Custom Solution

The other option you have is to build your own custom ad mediation into the app. This is obviously much more difficult to implement but it gives you the most flexibility. You can build it exactly how you want it.

Be aware though, if you want to be able to make changes on the fly like you can with a mediation service, you will need to set up a backend server as well and that can be a lot of extra work.

I’d recommend using one of the many mediation platforms out there first. It’s a quick, easy way to increase mobile ad revenue. If you find later on that you need something more substantial, then you might want to think about a custom built solution.


As always, I’d love to hear from you in the comments! Have you switched to a mediation platform? What were the results?

  • Mithun

    Thanks for your great post !! I’ve also read some others. Got another app mediation site Could you please tell me how much reliable this site for monetization.