8 Best Ad Exchanges for Publishers in 2021

Updated on: February 29, 2024
“Programmatic Ad Inventory Shouldn’t be Viewed as the Remnant Inventory”

Why do you need Ad Exchanges?

Ad exchanges (sometimes, referred to as programmatic ad exchanges) are one of the sought-after platforms in adtech, especially by mid-market publishers. As a publisher, you are leaving the money on the table if you have remnant ad inventory on your site or selling impressions at the subpar CPMs. But you can leverage it via a header bidding wrapper. With the advent of ad exchanges, publishers found a marketplace where they can connect with premium advertisers, and sell their remnant ad inventories at the best price in real-time.

Unlike ad networks, ad exchanges can offer you better CPMs (and more) while keeping the fill rate high. In fact, many publishers dropped the term ‘remnant inventory’ as programmatic exchanges have become sophisticated enough to trade impressions at premium prices. Now, it’s direct inventory and programmatic inventory – there’s no remnant. 

“Programmatic Ad Inventory Shouldn’t be Viewed as the Remnant Inventory”

– Michael Dugan, CTO, Hearst Magazines.

It wasn’t long before when a publisher had to call an advertiser, negotiate terms for ad inventories, and go through the whole insertion order process. Today, ad exchanges have entirely changed the process of selling and buying in programmatic advertising.

As you know, traditionally, ad inventories were used to be sold via ad networks where publishers had no control over the price or waterfall model which yielded lesser revenue than deserved. Now, header bidding and ad exchanges unite publishers, advertisers, agencies, and networks in one place enabling them to sell/buy ad impressions in a fully automated, and transparent manner. 

If you’re just starting out with ad exchanges or trying to find a better one, then here is the list of top ad exchanges (in no particular order) for you to try. 

Best Ad Exchanges For Publishers

The following is the list of best Ad exchanges for publishers.

Magnite (Rubicon Project)

Magnite started as a Sell-Side Platform (SSP) and then turned into an ad exchange later. It is one of the most transparent global platforms that has been widely used by top publishers like The Wall Street Journal, Conde` Nast, GAMELOFT, eBay, VOX MEDIA, and Turner. Bringing premium buyers to your website, the unified auction platform of Magnite assures publisher brand safety, greater yield in terms of revenue and impressions.


  • Connects to xAPI (Exchange Application Programming Interchange), its real-time exchange that optimizes revenue for the publishers and enables access to premium advertisers across the globe.
  • Magnite offers a variety of PMP deals which includes features like invite-only access to its selected premium buyers, higher CPMs, and greater fill rate by setting the priority level of a PMP deal, etc.
  • Its global programmatic video marketplace allows monetization of video ad inventory on-site & delivers the high-quality video ad content, thus high completion rates.
  • Magnite’s Unified ID solution benefits the publisher as it increases match rates and improves identity resolution outside of walled gardens, and hence earns more for their ad inventories.


Known as the publisher’s first approach, PubMatic comes with a unique advanced full-stack technology and data-driven monetization platform. PubMatic’s strategic decisions enable premium advertisers to reach publishers at scale. The ad exchange platform is equipped with a single dashboard that makes it easier for publishers to view their ad inventories, simplify ad workflows, and increase efficiency. Times Internet, Livingly Media, and many of the other top publishers have used this ad platform to bring demand from all parts of the world.

55B+ Daily Ad Impressions”


  • PubMatic Cloud offers holistic optimization & a customizable platform as a Service (PaaS) enabling a publisher to take advantage of DMP integrations, Advanced Analytics, CPS Management, Inventory Quality Controls, and many more services.
  • PubMatic’s Ad Exchange AdaptADX makes premium media inventories available to advertisers/agencies at scale with the help of programmatic channels on all devices and all formats.
  • PubMatic’s PMP-Guaranteed and Targeted model combined with its OpenRTB platform allows publishers to sell their ad inventories programmatically and gain complete control over factors that have access to their audiences.

Index Exchange

Index Exchange, an open and neutral ad exchange company, offers a global platform for digital publishers to sell their inventories and programmatic advertisers to buy authentic ad spaces for their brand. Benefitted by alliances with Integral Ad Science, The Media Trust, White Ops, and MOAT, Index Exchange grants an exceptional and transparent platform for both – publishers and advertisers.


  • Three Identity offerings – LiveRamp, Unified ID, and Merkle. These heavily encrypted real-time identifiers can target audiences across the globe based on different parameters. The identifiers can increase the number of bids, and bid price for publishers.
  • Its Business Intelligence-based software platform helps to view and access data. Apart from it, it has Wrapper Pulse API and an exchange tool that allows access to non-aggregated hourly data like impression data, revenue data, bid cycle data, geographic data, and many more.

Business Insider, The Economist, HEARST, MailOnline, The Telegraph, and many other top publishers have been working with Index Exchange for years.


OpenX is a highly optimized programmatic ad marketplace that enables publishers to take complete control over their ad inventories. OpenX Ad Exchange has an advanced integrated technology platform that combines real-time bidding and ad network with an SSP. Graphiq, Philly.com, and CarGurus are some of the publishers who have trusted OpenX and monetized their websites through an ad exchange.

60B+ Advertiser Bids Per Day


  • OpenX RTG (Real-time guaranteed) enables publishers and advertisers to do audience synchronization before getting into a deal to predict the number of impressions. The anticipated number of impressions are sold at a fixed price, eradicating the need for auctions.
  • OpenX Video solutions offer a wide range of variations in ad formats, integration methods, and selling models.
  • Certified “Against Piracy” under TAG’s IQG (Inventory Quality Guidelines), and hence offers a framework for brand safety.

Google AdX

Google AdX, the largest programmatic ad exchange, conducts the first-price auction and sells display advertising space in real-time. This Ad Exchange is the premium version of Google’s AdSense which was built for premium publishers and advertisers.


  • One of the best advantages of Google AdX over another ad exchange is that it asks for no money and has an easy installation process.
  • It allows publishers to display a wide range of ad formats to their visitors, and thus improving user experiences.
  • It enables a publisher to set up preferred deals for fixed CPMs with advertisers or private auctions with price floors with multiple buyers.
  • Also, Google’s AdX includes a dynamic price floor which automatically adjusts the price floor for ad inventory based on demand from buyers.
  • Google’s Ad Exchange offers account-level filtering and rule-based filtering which includes URL blocking, Google-certified Ad Networks, sensitive category blocking, advertisers blocking, cookies & data usage blocking, and so on.


AppNexus is a most advanced platform that enables publishers to increase the yield of their inventories in real-time. One of the best features of AppNexus’ programmatic ad exchange is its cloud-based software platform that improves the revenue for publishers by connecting them with third-party DSPs – all over the world. AppNexus’ Ad Exchange has been used by many top publishers including Microsoft, MiQ, Axel Springer, Underdog Media, and many more.

11.4B+ Impressions Per Day


  • AppNexus’ Publisher suite includes SSP, audience extension, ad serving, and forecasting. Besides this, the Publisher suite with open-source prebid.js code creates a stack that allows holistic optimization.
  • Its log-level data enables publishers to validate its inventories and checks whether these inventories are being sold fairly in an open marketplace.
  • AppNexus’ algorithm “Forecast Shaped Pacing” enables direct campaigns to more evenly distribute budgets throughout the day, which consequently opens up more inventories to programmatic demand during peak hours.


SmartyAds is an open-exchange and real-time bidding marketplace that functions as a bridge between web publishers and advertisers enabling the publisher’s side to sell their premium inventories across desktop or mobile.

135B+ Impressions Per Month”


  • SmartyAds’ white label ad exchange platform enables publishers to access unlimited advertisers from all over the world and sell their inventories on their own terms.
  • Offers CPI, an AI-based full-stack solution, that helps app publishers to reach potential buyers, making sure that the publisher gets a maximized revenue.
  • Its auto API integrated solution consists of an in-built anti-fraud solution known as Fraud score which provides extra protection from bots and frauds.
  • Consists of GAID (Google Advertising ID)/IDFA (Identifier For Advertising) targeting that helps publishers to identify the relevant audience and display ads as per their preferences.


Smaato is one of the global mobile advertising platforms which is helping app publishers and mobile developers to increase revenue with dynamic demand, access to hundred demand partners, and full monetization control. More than 90,000+ publishers have access to 10,000+ advertisers. Smaato has worked with some of the top leading tech partners like MOAT, Forensiq, and Protected Media.

500B+ Ad Requests Per Month”


  • Smaato’s Publishers RTB Ad Exchange (SPX) finds the best ad price in milliseconds, yielding higher eCPMs, ad quality, and more transparency.
  • To fight against ad frauds, Smaato has auto-detection methods that use machine learning and advanced algorithms. If the algorithm detects anything malicious, then it automatically blocks it, resulting in the best quality of traffic for its publishers.
  • With its first open-source viewability measurement SDK, Smaato integrated Moat for enhancing transparency and viewability.


Digital advertising is a vast and dynamic industry that keeps on bringing new technologies, formats, and platforms every other day. While the above-mentioned ad exchanges can be considered as the best ones, there are many other companies that offer exchanges. Some of them are designed to work for mobile ad inventories (like MoPub) and some are designed only for video (like Unruly). We advise you to experiment with the suitable ones and then, run with the best ad exchanges. 

That being said, most of the mid-market publishers have issues partnering with ad exchanges directly – either because of the inflated requirements to get in or as they need to hop from one partner to another to get things done, themselves. Also, some ad exchanges are primarily targeting enterprise publishers with hundreds of millions of impressions (for instance, AppNexus) and some have a stringent minimum threshold to onboard a publisher (for instance, Google Ad Exchange).

We can get you access to the best ad exchanges, including Google Ad Exchange (we’re a Google MCM Partner), and handle the setup and optimization for you. Feel free to reach us anytime

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