How to Build an Ad Server: 3 Ways From Hardest to Easiest

“Ad placement is easy, building an ad server should be too, right?”

No, it is not! But it is far easier than it has ever been. Just like in modern video games, you can choose a difficulty level at the start of your journey from an in-house ad server, API-based ad server, or a white-label ad server.

How are they different? Which is the most affordable? Which is better for which business? Did X influencers lie to you about the fact that building an ad server is easy? Let’s not waste any more time and find out!

Hard: How to Build an Ad Server In-House

Okay, you’re tough as nails, and up for the hardest route – building an in-house ad server.

First of all, you have to understand that much like building your own ad network, this is a multi-leveled journey where you control every step.

How to Build an Ad Server In-House Step by Step

Before we even start, we have to warn you about the costs and time of in-house advertising. On average, ad companies require from 1 to 2 years to build their ad server. The yearly cost of development reaches up to $1 million, and we don’t even include maintenance costs and salaries.

Why the hell is this so expensive? Well, to understand that, here’s how to build your ad server in-house:

Step #1. Hire a team

It usually consists of a lead architect, backend/frontend engineers, DevOps, data scientists, and QA. That’s the initial set-up, you’ll most likely expand it with content creation and support teams to grow and advertise in the future.

Step # 2. Define Your Requirements

What do you need an ad server to do? Do you plan to leave it for internal use or sell it as SaaS? Either way, you need to be competitive, and simply serving and hosting ads ain’t gonna cut it in 2025.

That’s why, consider implementing at least these features:

• Auction mechanics (first/second-price auctions);
• Targeting features (zone/placement/time/demographic/behavioral);
• Retargeting;
• Bidding by metrics (CPM vs CPC vs CPA);
• eCPM auctions;
• Pixel tracking/conversion tracking/revenue tracking;
• Campaign hierarchy;
• Multiple ad format support;
• Reporting/real-time analytics;

Is this all? Nope. Here’s a handy list of ad server competitors on the current market, so you know what you’re up against.

Step # 3. Build Backend & Infrastructure

Time to pick all of the above and give it a nice ad decision engine, interface, and basic reporting dashboard. If you’re thinking about SaaS, then user role management (with super-admin/admin/user access) is preferable as well.

Also, if you want to grow and scale, it would be nice to have a decent infrastructure. We’re talking things like cloud hosting, CDN integration, load balancing, etc.

Step # 4. Stress Test

Okay, now it’s time for testing. How do industry specialists usually do it? They simulate millions of bid requests per second and watch if the ad server still works under pressure. The error rates, the latency, the uptime – everything is taken into account.

Step # 5. Launch Beta

Time for a closed beta. Onboard the publishers and advertisers, you know and ask them for opinions. Collect feedback, fix the bugs, and optimize performance. Only when you’re certain that your product is functional can you release it.

Remember – it’s better to roll out a finished product than to rush and ruin your reputation. This fate happens, unfortunately, more often than it should in our industry (sorry, TTD).

Step # 6. Iterate & Expand

The basics are done. Now it’s time to grow. Add new features, improve your bidding rules, optimize the flow, and fix the mistakes. Trust us, an ad server is like your grandparents’ house in the village – there’s always stuff to do.

If you’re planning on SaaS, don’t forget about compliance and regulations. Also, there’s marketing work to attend to. This is a solid chunk of load, but a dedicated marketing team is the best way to generate leads, especially in an environment as violent and competitive as ad tech.

Who Needs to Build an In-House Ad Server?

• Full ownership of the platform. No markups and middlemen;
• Infinite flexibility and customization. No reliance on providers;
• Real IP value;
• Long-term business investment;

As for the cons, they are a natural price for all of this freedom.

• Enormous costs;
• Massive time investments;
• A lot of effort and expertise require;
• Huge chances to go broke;

Building your own native ad server is a step for huge companies that already have their stuff together. If you aim to dethrone AdButler, AdGlare, or Uprival, or simply have enough time & resources to invest them into your own complex ecosystem, then this is an option for you.

Otherwise? Keep reading.

Medium: Build an Ad Server with API

Let’s assume you are not an industry giant with millions of dollars ready for investment, but you still want your own product.

How to Build Your API-Based Ad Server

The premise is simple: you use somebody else’s API for back-end logic and develop your own front-end.

The provider options exist, but aren’t that plentiful. You can try Kevel, Amazon Publisher Services, or stick to Epom.

What do you get when building your ad server with Epom API, for instance?

• Access to a powerful base with many targeting options, various ad formats (including custom), optimization features, etc.;
• Ownership of your brand experience;
• Full freedom to create your own interface, features, workflows;

With an API-based solution, you decide how your platform looks and feels and how your users interact with it, without needing to develop bidding logic from scratch or handle 500M daily requests.

The cool thing is it’s quite easy to use. For example, all you have to do with Epom’s API is:

1. Set up a Postman workspace.
2. Authenticate with your Epom API token.
3. Use simple REST API calls to create campaigns, upload banners, set targeting options, fetch analytics, and reports.
4. Build your custom front-end that sends and receives these calls behind the scenes.

You can literally start testing by sending "Create Campaign" commands in Postman before a single line of UI code is written.

Who do you need on your team? Usually, you’ll require:

• Frontend devs (for UI, duh);
• Backend devs (unless you can handle API integration and user authentication on your own);
• API Specialist or tech PM (with Epom, you can count on our help);

As you can see, the number of hires is substantially lower than what you’d have with an in-house solution. The benefits of an API-based ad server are also sweet, so where’s the catch?

In the end, you still have to accept compromises:

• Backend logic remains dependent on the provider;
• You still pay for impressions and for white-labeling;
• Server uptime, compliance, and the number of bugs depend on the provider;

Who Needs to Build an API-Based Ad Server?

It’s much easier, quicker, and cheaper to build an API-based solution than an in-house one.

Yes, they have their limitations, but think of the good stuff. The backend is already there, so depending on your devs, you can finish the front-end part in 3-6 months. You only pay for impressions and white-labeling; maintenance costs and support are on the provider side.

It’s a great option for mid-sized ad networks and performance agencies, or simply for the ad businesses that want their own solution but lack development resources for a solid base.

Still confused? Here’s a great video where our CSO Serhiy Shchelkov explains how to build your own API-based ad server with Epom:

Easy: “Build” a White-Label Ad Server

Do you want an ad server, but don’t have months to build or cash to burn?

How to Build a White-Label Ad Server

Okay, to be fair, you don’t actually build anything in this option. But it doesn’t make opting for a white-label ad server any worse.

White-labeling is basically the fastest and easiest way to build your own native ad server. All you do is subscribe to a service like the Epom white-label ad server and pay monthly, depending on the number of impressions served.

What do you get?

• Your own domain name (e.g., toaster-lovers.com);
• Your own branding in the UI (logos, colors, etc.);
• Full feature set (campaign management, audience targeting, reporting, analytics);
• Advanced user management (separate access for users and admins);
• Fast onboarding (1-2 weeks);
• Dedicated support team;
• Custom development, should you require it;
• Affordable pricing and scaling (pay per impressions and white-labeling without hidden fees);

Moreover, you can significantly save on hiring a team. Surely, a branding designer and frontend developer are a great bonus, but most of the tasks you can handle either yourself (media buying & selling) or leave it to our team (account managing and support).

What about the limitations? They are similar to what you’d have with an API-based ad server:

• Backend updates are handled by the provider, so the screw-ups are on them as well;
• Deep customization and features require additional development (we provide it at an additional cost)
• You still pay for impressions and white-labeling;

Who Needs to Build a White-Label Ad Server?

Obviously, a lot of businesses can benefit from renting a ready-to-use technology branded as their own. We’re talking about:

• New ad networks launching with their own branded tech stack;
• Publishers and advertisers of all sorts and sizes;
• Agencies that are interested in ways to expand their media buying;

Basically, anyone who wants to run their branded ad stack with customization, scale, and advanced features in mind is the target audience for this solution.

Bonus: Building an Open Source Ad Server

Okay, what if you’re short on cash, but have enough skills and expertise to compensate. Well, you could theoretically use an open-source ad server like Revive. We’ve already explained why, for most people, the choice between open-source vs hosted ad server comes down to the latter.

Here’s a short synopsis:

• You manage maintenance costs;
• Server costs are on you as well;
• Support is missing;
• Security is lacking;

In short, building an open-source ad server is like building a skyscraper with Lego. Possible, but painful.

Which Ad Server to Build?

Let’s sum it up:

• If you’re sitting on $1M+, a dev team fluent in RTB auction protocols, the patience of a saint, and the ambition of an emperor, build it yourself.
• If you want to own your customer experience, move faster, and still keep tech costs sane, go API-first.
• If you want speed, simplicity, and serious firepower right out of the box, opt for a white-label solution.

Still not sure whether the white-label ad server is as good as we tell you? Get access to a demo account and check for yourself.