Programmatic display advertising, from the seller's side

Programmatic display advertising is the automated buying and selling of banner and other visual ad slots on websites and apps, usually through a real-time auction that runs as each page loads. For a publisher, it means every display slot on your page is offered to many buyers at once, and the best qualifying bid fills it.

Here's the problem. Nearly every guide to programmatic display is written for advertisers: how to pick a DSP, how to target audiences, how to set a budget.

If you run the website, you're on the other side of that auction, and your questions are different. Why does this slot earn less than that one? Which sizes should it accept? Do more ads mean more money?

This guide answers those from the seller's side. You'll see how programmatic display works step by step, how it differs from "display ads" and the Google Display Network, how your slots get sold, and the settings that change what each one earns. If you'd rather have the auction set up for you, our header bidding service does exactly that.

What is programmatic display advertising?

Programmatic display advertising is display advertising sold by software instead of by a person sending insertion orders. "Programmatic" describes how the ad is bought. "Display" describes what it looks like. Put together, it's image and rich-media ads sold through automated auctions or automated deals.

That's the short answer to "what is programmatic display advertising?" The longer answer matters because the two words get mixed up all the time.

What counts as display

• Standard banners. The fixed sizes most sites run: 300x250, 728x90, 320x50, 300x600 and 160x600. Our guide to banner sizes shows which ones earn their place.
• Rich media. Banners that expand, animate or carry a small video player inside the slot.
• Interstitials and anchors. Full-screen ads between pages and sticky bars at the top or bottom of the screen.
• Native display. Ads styled to match your page, usually in a feed or under an article. Some buyers count these as display, some as a separate channel.

Instream video before a video player and CTV ads are usually sold programmatically too, but they aren't display. They have their own formats and their own buyers.

What counts as programmatic

Programmatic covers any automated sale: the open auction anyone can bid in through real-time bidding, private auctions for invited buyers, and fixed-price deals that software delivers. The common thread is that a machine decides, impression by impression, which ad runs. AdSense is programmatic display too. It's just a closed version where Google runs the whole auction for you.

How does programmatic display work, step by step?

Programmatic display works as a chain: your page asks for an ad, your ad stack sends a bid request to many buyers, they bid, your ad server picks the winner, and the creative loads in the slot. It all happens while the page is loading, and it happens again for every slot on every page view.

1. The page loads and an ad tag fires. Each display slot has a tag: a Google Publisher Tag for Ad Manager, an AdSense unit, or a Prebid ad unit. The tag says which sizes the slot accepts.
2. A bid request goes out. Your SSPs and exchanges send buyers a description of the impression, usually in IAB Tech Lab's OpenRTB format. For display, that's a "banner" object listing the accepted sizes, plus the page URL, the device and whatever consented data you pass.
3. Buyers decide and bid. Demand-side platforms (DSPs) check the impression against their campaigns and send a price, or pass. Our DSP vs SSP guide explains both sides of that exchange.
4. The auction picks a winner. Your header bidding wrapper collects bids in the browser, then your ad server compares them with its own demand and any direct deals. In Google Ad Manager, the auction picks the highest net bid, and the winning buyer is never charged more than it bid.
5. The creative renders. The winning ad loads in the slot, the impression is counted, and viewability is measured once the ad is on screen.
6. You get paid. Each party in the chain takes a fee, and what's left reaches you on each partner's payment schedule.

The parts of the chain, from your side

Every programmatic display sale passes through some of these systems. You only run a few of them yourself, but it helps to know who does what when you read a report.

Data is optional. Plenty of sites earn well with no DMP at all, using page context and Ad Manager's built-in tools. A DMP is worth paying for only when you sell audiences directly.

The step most publishers can actually change is step 2. More competing buyers, accurate sizes and clean data in the bid request all raise what gets bid in step 4. A slot nobody can see or measure gets low bids, however good the content around it is.

Programmatic vs display ads, and where the Google Display Network fits

Programmatic vs display ads isn't a real choice: programmatic is a way of selling and display is a format, so most display ads today are sold programmatically. The useful comparison for a publisher is between the routes your display inventory can be sold through.

Google Display Network vs programmatic

The Google Display Network vs programmatic debate is an advertiser's question. From your side, the Google Display Network is one buyer group among many. When you run AdSense, Google Ads advertisers are the main demand. When you move to Ad Manager with Google Ad Exchange or add header bidding, those same advertisers still bid, but now they compete with other DSPs for the same slot.

That competition is the whole point. We've written up the trade-offs of moving beyond AdSense in AdX vs AdSense.

How your programmatic display slots get sold

Your programmatic display slots can be sold in four ways: the open auction, private auctions, preferred deals and programmatic guaranteed. Most publishers start with the open auction and add deals once buyers ask for them.

In Ad Manager, Private Auctions handle the second row, and Programmatic Direct covers preferred deals and programmatic guaranteed. Our guide to programmatic advertising for publishers follows the money through each deal type in more detail.

Deals need demand. A site with a general audience and modest traffic rarely gets deal requests, and that's fine. The open auction does most of the work for most sites.

What decides what your programmatic display ads earn

Your programmatic display ads earn more when more buyers compete, when the slot is likely to be seen, and when buyers know what and who they're bidding on. Page topic and visitor country matter too, but those are harder to change. Here's what you can change.

Viewability

A display ad counts as viewable when at least 50% of its pixels are in the browser window for one continuous second. For large ads over 242,000 pixels (a 970x250 billboard, for example), 30% of the pixels is enough. That's the IAB definition Google's Active View help page uses. Buyers who pay only for viewable impressions bid less, or skip, slots with a poor viewability history.

Say 100 impressions load on a page, and 40 of them are ads at the very bottom that few people scroll to. If only 5 of those 40 are seen, those slots drag down your page's viewability rate, and buyers price that in. One well-placed in-content slot often earns more than three footer slots.

Ad sizes and multi-size slots

Accepting more sizes in one slot lets more creatives compete. A sidebar slot that takes 300x600 and 300x250 has more bids to choose from than one that only takes 300x600. On mobile, a 300x250 in content and a 320x50 anchor cover most of the demand. Odd custom sizes get very few bids, because almost no campaign has a creative that fits them.

Number of bidders

More real competition raises the clearing price. That's what header bidding does: it lets several SSPs bid at once instead of one after another. Adding a tenth SSP that buys from the same DSPs adds little, though. In our reviews, a short list of strong, different demand sources does better than a long list that slows the page.

Header bidding vs Open Bidding

Header bidding and Open Bidding both add buyers to your display auction, but they run in different places. Header bidding runs in the browser: Prebid's docs describe it as collecting "bids before the ad server is called," with the ad server making the final decision. Open Bidding runs on Google's servers, inside Ad Manager, so it adds no code to your page.

• Header bidding: more control and more choice of partners, but more scripts in the page and more setup.
• Open Bidding: lighter on the page and quick to switch on, but you're limited to the exchanges Google supports and you can only use it inside Ad Manager.

Many publishers run both. That's fine, as long as you watch page speed and don't call the same SSP twice.

Price floors

Floors stop your slots selling too cheaply, but set them too high and slots go unfilled.

In Ad Manager, pricing rules let you manage floors for your non-guaranteed demand in one place: the open auction, Private Auctions, Open Bidding exchanges and remnant line items. They don't apply to Programmatic Direct deals, which have their own negotiated price. Sellers are paid the closing price after Google's share, but never less than the floor, according to Google's auction model page. Start low, raise floors in small steps by country and device, and watch fill rate and eCPM together. Our eCPM guide explains why eCPM alone can mislead.

Clean supply files

Buyers check your ads.txt file before they bid. IAB Tech Lab's ads.txt standard lets you list every company allowed to sell your inventory, so a missing line means that seller's bids are often dropped. Our ads.txt guide for publishers covers the file line by line.

Page speed and layout

Slow pages lose impressions before the ad even loads, and ads that push content around annoy readers. Google's web.dev guide on layout shift recommends reserving space for ad slots so the page doesn't jump when an ad arrives.

How to set up programmatic display on your site

To set up programmatic display, fix your supply files first, then your layout, then add demand and floors, and measure after each change. This is the order we work in when we review a publisher's display setup, because each step makes the next one pay off.

1. Check ads.txt and sellers.json. Every partner's lines must be in ads.txt at your root domain, and your seller ID should appear in each partner's sellers.json.
2. Plan the layout. Pick a few display slots per page where people actually look. We usually start with one near the top, one or two in content and one sticky anchor on mobile. Skip slots below long comment threads.
3. Create one ad unit per placement. Name ad units by page type and position ("article_incontent_1", "sidebar_top") so reports show which placement earns what. One generic unit used everywhere hides the answer.
4. Reserve space for each slot. Give each ad container a minimum height for its most common size so the page doesn't shift.
5. Connect demand. Start with AdSense or Ad Manager. Once you have the traffic, add Google Ad Exchange and a header bidding wrapper. Our Prebid.js setup guide walks through the wrapper.
6. Accept the right sizes. Map each slot to every standard size that fits the space, not just one.
7. Set floors. Use Ad Manager pricing rules (or your wrapper's floors) by country and device. Start low.
8. Lazy-load lower slots. Request ads just before they scroll into view, so you don't sell impressions nobody sees.
9. Measure for two weeks. Track viewability, fill rate, eCPM and page RPM per slot. Change one thing at a time.

The numbers to track per slot

Track these four numbers for each ad unit. Together they tell you whether a slot is worth keeping, moving or dropping.

Common programmatic display mistakes we see

The most common programmatic display mistakes are too many ad slots, ads that shift the page, missing ads.txt lines and floors set once and never touched. Each one costs revenue quietly, so you won't see an error message.

• Too many units. Ten slots on a short article dilute viewability and slow the page. Buyers notice.
• Intrusive formats. The Coalition for Better Ads' Better Ads Standards list the ad experiences people find most annoying. On mobile they include pop-ups, prestitial ads, flashing animated ads, full-screen scrollover ads, large sticky ads and ad density higher than 30%. On desktop, ad density over 50% fails. Keep clear of all of them.
• Layout shift. Slots without reserved space push text down as ads load. Readers leave, and accidental clicks can get flagged as invalid traffic.
• Stale ads.txt. A partner added a new seller ID and nobody updated the file. Their bids drop and you don't know why.
• Forgotten floors. A floor set in January can block half your mobile demand by June. Review floors monthly. Floors left over from the second-price era are the usual culprit, because buyers now shade their bids toward the minimum that wins (see what bid shading does to your floors).
• Refreshing too fast. Reloading ads on a timer without telling buyers breaks most partner policies. If you refresh, follow each partner's rules and declare it.
• One ad unit for everything. When every slot reports as the same unit, you can't tell a strong placement from a weak one, so you can't fix either.

Pros and cons of programmatic display for publishers

Programmatic display gives you more buyers, steady fill and little sales work, in exchange for less control over which ads run and a share of each sale going to the middlemen. For most sites the trade is clearly worth it.

The cookie worry has eased, too. In October 2025 Google said Chrome will keep offering users a choice on third-party cookies, in its Privacy Sandbox update. Safari and Firefox still block them by default, though, so page context and your own first-party data stay the parts that last.

You can control brand safety with your ad server's blocking controls: block categories, advertiser domains or sensitive topics you don't want on your pages. Just don't block so much that you thin out the auction.

Frequently asked questions

Is AdSense programmatic display advertising?

Yes. AdSense sells your display slots automatically through Google's auction, so it's programmatic. The difference is that Google is the only seller, and you can't add other buyers, run deals or set detailed floors. Ad Manager and header bidding open that up.

Is the Google Display Network programmatic?

Yes, on the buying side. Advertisers buy Google Display Network placements through automated auctions in Google Ads. For you, it's one source of programmatic display demand, which reaches your site through AdSense, AdMob or Google Ad Exchange.

What are the most common programmatic display ad sizes?

The sizes with the most demand are 300x250, 728x90, 320x50, 300x600 and 160x600, plus 970x250 on wide desktop screens. Let each slot accept every standard size that fits the space, so more ads can compete.

How much does programmatic display pay?

There's no fixed rate. What programmatic display pays depends on your visitors' countries, your topic, the device, viewability, the season and how many buyers compete. Compare your own page RPM month over month instead of chasing published averages.

Do I need header bidding for programmatic display?

No, you can start with AdSense or Ad Manager alone. Header bidding becomes worth it once your traffic is steady enough that extra competition lifts prices more than the setup and page-speed cost. We can tell you if you're there.

What's the difference between programmatic display and native ads?

Programmatic display usually means standard banner formats with fixed sizes. Native ads are built from parts (headline, image, brand name) and styled to match your page. Both can be sold programmatically, often through the same SSPs.

Next step

Programmatic display works best when every slot is seen, sized for real demand and open to several buyers. If you'd like us to review your current layout, ads.txt and demand, contact MH AdX and we'll tell you what we'd change first.