When (not) to
use Kleio

We’re really proud of what Kleio can do—it’s a solid piece of software. That said, it isn’t the perfect fit for every project out there. Below, we’ll share where Kleio shines and also point out some situations where you might want to consider a different ad server instead.

Kleio works well if your needs align with the following cases:

Sponsored products in lists

If your website or app features any kind of lists—like recommendations or user-contributed posts—Kleio is designed to seamlessly integrate sponsored items right where you need them. This is exactly what we built Kleio for.


If your application generates a list of relevant items for a user — like search results or personalized recommendations — and you end up with far more items than you intend to display (imagine your search engine pulls up 200 results but you only want to show the top 10), then Kleio is perfectly suited for the job. It can help re-order these items and convert them into sponsored content seamlessly.

Here's a practical example: Suppose you're an online grocer and a user searches for "soda." You might have around 100 soda-related products you could show them. To keep things clear and focused, you decide to display only the top 10.

To enable sponsored listings and allow suppliers to boost their products, you send all 100 alternatives to Kleio before finalizing the top-10 list. Kleio then examines these alternatives, checking if any have ads associated with them, and conducts a live auction among the available candidates.

This approach has many benefits:

  • It retains the relevance of your highly optimized search – i.e. no ad for diapers would accidentally appear among the soda
  • It is conceptually simple and can be used in all cases where your lists have more items than you have space to show.
  • It avoids the need for cumbersome and manual definitions of keywords

Effortless GDPR compliance

The Kleio ad server operates on-premises and remains entirely under your control, ensuring no information is shared with third parties. Additionally, it does not engage in any data collection, not even internally, which greatly simplifies privacy compliance.

No Need for a Cookie Banner

Kleio does not use cookies or any form of personalized tracking. As such, there's no need to account for or declare it in your cookie banner.

Consider an alternative to Kleio if you need any of the following capabilities:

RTB (Real Time Bidding)

Kleio does not support integration with third-party ad networks, including DSPs (demand-side platforms) and SSPs (supply-side platforms). Instead, it relies on you supplying your own ad inventory directly to the Kleio ad server.

Hosting Assets

Kleio does not host assets itself. However, you can still display banner ads using Kleio by including details about the asset in the metadata associated with each ad. This approach informs your server about which asset to serve.

No direct access from clients

The Kleio API should not be exposed to untrusted clients, including your own applications accessed by untrusted users. It is designed to be used by server-side applications within a trusted environment.

If you're working with a native app and lack a backend service to act as a proxy between the client and Kleio, then Kleio may not be a fit for your needs.

No Interface for Placing Ads

Kleio is designed to function as an API and does not provide an interface for partners or suppliers to create or pay for ads. Building such an interface is your responsibility. However, this also means that the interface you develop will align with your own design principles, and it opens up possibilities for integrating a variety of services on top of Kleio.