Programmatic advertising is the buying and selling of ad space through software and automated auctions instead of human negotiation, impression by impression, in milliseconds. The advertiser sets who to reach, on which sites and at what price through rules and data; the publisher offers its inventory to many buyers at once. eMarketer forecasts that about 91.5% of global digital display ad spend is programmatic in 2026.
Programmatic is not a channel but a buying method: display, video, connected TV, digital out-of-home and audio can all be bought programmatically. Platforms such as Google's Display Network and Criteo also run on programmatic infrastructure.
How does programmatic advertising work?
When a user opens a page with an ad slot, the publisher's SSP offers that impression to an ad exchange. Advertisers' DSPs bid based on user and context data; the highest valid bid wins and the ad is shown as the page loads. The process typically completes in about 100 milliseconds, so the user notices no delay.
- DSP (demand-side platform): where advertisers or agencies buy impressions and manage targeting, bids and budget.
- SSP (supply-side platform): where publishers offer their ad inventory to many buyers.
- Ad exchange: the auction environment that connects DSPs and SSPs.
- Data layer: first-party data, CDPs and contextual signals, which matter more as cookies fade (first-party data strategy).
What are the programmatic buying types?
Programmatic is more than the open auction. Three main models strike different balances between price, control and inventory quality; large advertisers usually use all three.
- Open auction (RTB): open to all, widest reach and most flexibility; inventory quality varies.
- Private marketplace (PMP): an invite-only auction run by selected publishers; better brand safety, usually higher prices.
- Programmatic guaranteed: fixed price and volume agreed in advance but delivered automatically; for large brand campaigns.
See Criteo and your other channels on the same yardstick
Ads Sensor unifies Criteo data with Google Ads, Meta, TikTok and GA4 and compares channels.
How is programmatic advertising used in ecommerce?
The most common ecommerce use of programmatic is retargeting: showing a product, or similar ones, across the open web to users who viewed it or abandoned their cart. Commerce-focused platforms such as Criteo build dynamic ads from product feeds and on-site behavior and are widely used for this (Criteo ads guide). Google's Display Network and Demand Gen campaigns meet a similar need on Google inventory (Google Display ads guide).
- Dynamic retargeting: automatically showing the products a user viewed, from the feed.
- Lookalikes and new customer acquisition: reaching users who resemble existing customers.
- Retail media: programmatic inventory run by marketplaces and retailers on and off their own sites.
- Frequency management: capping over-exposure to the same person (remarketing strategy).
What are the risks of programmatic advertising?
The speed of automation comes with a loss of control. Part of every programmatic budget goes to intermediaries in the supply chain rather than to the publisher, and industry studies suggest that share can be significant. There is also the risk of low-quality sites, bot traffic and appearing next to unsuitable content.
- Brand safety: use block lists, allow lists and content category exclusions.
- Invalid traffic: use verification tools and check authorized sellers via ads.txt and sellers.json.
- Viewability: limit paying for impressions that are never seen; track viewable impression metrics.
- Measurement bias: view-through conversions can overstate programmatic's contribution; validate with incrementality tests.
How does Ads Sensor help with programmatic channels?
Ads Sensor brings your Criteo account together with Google Ads (including the Display Network), Meta, TikTok and GA4 in one panel. It helps you compare whether programmatic retargeting truly adds sales, on the same yardstick as other channels; AI analysis prioritizes cost and conversion deviations and proposes reasoned actions. Buys run through your own DSP (for example DV360 or The Trade Desk) are not currently among the supported integrations. Apply for the beta.