By Freddie Turner, Managing Director, EMEA, Chalice AI
For much of programmatic’s history, decision-making has leaned heavily toward the buy side. Brands, agencies and DSPs have set the rules: who gets targeted, when, and at what price. The sell side publishers and their tech partners have traditionally played a more reactive role, making their inventory available and relying on the buy side to determine value and placement but that’s starting to change.
A quiet but important shift is underway. Sell-side decisioning (SSD) is creating new space for intelligence earlier in the programmatic process. Decisions about what impressions to prioritise, how to score quality and what context matters aren’t being left to chance or waiting until a bid request is fired off. Instead, those questions are increasingly being answered upstream.
Let’s think of it like buying a house. For years, media buyers were choosing where to live based on curb appeal – they liked the neighbourhood, so they made a move. But SSD is like getting access to the floor plan before you buy: you know how many bedrooms there are, how big the garden is and what the layout looks like. You can assess real value before anyone else even sees the listing.
The page-level, contextual, real-time visibility opens up smarter, faster decision-making. It’s no longer just about reacting to an open auction; it’s about curating what goes into the auction in the first place.
One of the more promising aspects of SSD is how it enables better alignment between advertiser goals and media environments. Consider a brand focused on family audiences and creative engagement. They’re not just looking for reach they’re looking for relevance: safe, engaging, content-rich spaces that reflect their values.
Historically, that’s been tough to guarantee at scale. But with SSD, publishers (and their partners) can pre-filter inventory based on page-level insights like suitability, attention potential and contextual fit. In many cases, that leads to higher-performing outcomes. Not because the CPMs are lower, but because the impressions are better.
Much of this evolution comes down to infrastructure. The traditional programmatic stack wasn’t designed for flexibility. Adding custom filters or logic often required heavy integration, bespoke code and months of lead time.
That’s where containerisation comes in. Modern SSD approaches now use modular, pluggable containers allowing decisioning models to be deployed and updated quickly, without rewriting the plumbing. This kind of agility is what makes it possible to respond to brand-specific needs in real time.
It also allows for more experimentation. Want to test a new brand safety model? Drop it into the container. Want to score impressions based on an attention index? Done without waiting for a quarterly roadmap slot.
This isn’t about replacing the DSP it’s about improving the signals it receives.
DSPs remain the core engine of scale, frequency and budget control. SSD simply adds another layer of intelligence earlier in the process, enriching the quality of what makes it into the DSP in the first place. In many ways, it lets the DSP do its job better.
In that sense, SSD and DSPs aren’t competitors. They’re collaborators each doing what they do best and collectively enabling smarter programmatic.
As privacy regulations evolve and third-party signals decline, SSD may become less of an innovation and more of a necessity. It enables more responsible use of first-party data, more nuanced contextual targeting and more flexibility at the infrastructure level.
More importantly, it invites a different mindset – one where decisioning isn’t confined to a single side of the auction. Instead, intelligence is shared, applied earlier and used to build campaigns that work better for brands, publishers and audiences alike.
The rebalancing of programmatic isn’t loud. But it’s happening.
And those who tune in now will be better placed to lead where it goes next.
