Based on the observation that many budgets are wasted at Meta and Google, experts from Antvoice are launching an AI start-up to allow brands to correct the situation.
Stelleo, a new buy-side adtech platform born in France with the specificity of being above all agentic, wants to enable advertisers to obtain performance gains of around 20 to 30% among Gafam. How ? By acting as co-pilot on the advertiser’s account on these platforms. “Stelleo agents recover all the data that is present on advertisers’ Google Ads or Meta Ads accounts, data that is often difficult to action,” explains Alban Peltier, CEO of Antvoice, co-founder of Stelleo with Rodolphe Mirilovic, CTO of Antvoice and Ludovic Vannier, VP sales.
The Gafam consoles sort the information that comes back. However, when it comes to advertising, the devil is in the detail. “Most advertisers and many agencies do not have sufficient expert human resources to systematically dig into these opaque environments.” And this is the value of Stelleo’s team of AI agents, who sift through everything, ensures the company: performance by device, time, day, creative, target, strategy, etc.
This is how, for an advertiser in the travel sector, the tool revealed that 23% of the media budget dedicated to Meta was poorly invested, the platform having made the decision to double the share of retargeting for zero additional return without the advertiser even being informed. Another example: for a meal delivery company targeting seniors, 80% of the campaign budget was deployed on the target that performed the least well, that of people aged over 65, instead of mainly targeting younger targets, caregivers, presenting an ROI three times higher. Finally, for another campaign taken on the fly at the time of our interview, the tool made it possible, in a few seconds, to detect the way to double performance simply by highlighting all the activations on specific targets and geographies giving a weak return that it was high time to cut! “This analysis would have easily required a few hours from an expert for the same result,” assures Alban Peltier.
“We can optimize advertisers’ budgets by 20 to 30%, at least that’s the objective we set ourselves and what we observe in the tests at the moment,” he continues. Stelleo claims more than 10 million euros of media investments currently being tested, from around ten advertisers in retail, travel and services. Enough to allow it to demonstrate that by penetrating the bowels of Gafam with the sole aim of meeting the objectives of advertisers, these AI really act in the interest of the latter.
But to achieve this result, the Stelleo teams had to inject a lot of business intelligence and a whole algorithmic layer in order to make the LLMs sharp on the subject. Agents analyze, recommend and execute optimizations, under human supervision and validation. With one important detail: the advertiser interacts by asking questions to agents in real time.
The platform is functional on Google Ads and Meta Ads, and also works on the programmatic open web. Ultimately, the plan is to also integrate Amazon, TikTok and CTV. A private beta has been open since Thursday June 11 by invitation. The open beta will be available starting in October.
On the economic model side, the bet is clearly industrial: the adtech will target volume by offering an ultra-competitive price made up of a subscription of 399 euros per month and 3% of the campaign budget to be optimized. Enough to mix widely, by integrating large advertisers with VSEs, from large agencies to small structures. Stelleo will be supported by a small seed round currently being closed and is setting itself the target of 1,000 customers by the end of 2027 with the ambition of being profitable from the start.
A strong bet which will be validated in a very short time and which will perhaps serve these entrepreneurs to ensure the succession, in the long term, of their original activity in a world of digital advertising where the open web is less and less successful. A perspective that any seasoned adtech professional would be crazy not to consider even if Antvoice is doing well and even very well according to our interlocutor: profitable for four years, it grew 10% in the first half compared to the same period of 2025.
