Koah, a native monetization platform for generative AI, has closed a $20.5 million Series A led by Theory Ventures, with Tomasz Tunguz joining the board.
The round follows a $5 million seed in September 2025, bringing Koah's total funding to more than $26 million. Existing backers Forerunner and South Park Commons continue to support the company alongside the new investment. Tomasz Tunguz, Founder and General Partner at Theory Ventures and a former Google AdSense team member, will take a board seat as part of the deal.
Koah's pitch is straightforward: generative AI has become the way millions of people search, compare products, and make decisions, but the monetization tools available to developers still belong to the web era. Banner ads and subscription paywalls don't translate well into conversational interfaces, and high inference costs make it hard for AI apps to run on subscriptions alone.
The company's lightweight SDK lets developers embed native, contextual advertising directly inside AI chat experiences. Instead of interrupting a conversation, ads appear as relevant suggestions tied to what a user is actively researching. The format is designed to feel useful rather than intrusive.
"Subscriptions models alone don't scale given high inference costs, and legacy ad models erode user experience," said Nic Baird, Koah's Co-Founder and CEO. "At Koah, we're designing monetization infrastructure specifically for AI that's additive for end users and revenue-driving for developers."
AI apps are growing at a pace that advertising infrastructure hasn't kept up with. Users increasingly turn to tools like Liner, Perplexity, or custom AI assistants not just to find information but to form opinions and make purchase decisions. That shift creates a high-intent environment that advertisers have struggled to access through traditional channels.
Koah's ecosystem now reaches more than 2 million monthly active users, each engaging with conversational AI an average of three times per day. To date, the platform has served over 35 million native ad impressions across 175 million queries, a data point that signals real traction beyond pilot stage.
"We're seeing users research, compare, and form brand preferences directly inside AI tools," said Luke Kim, CEO of Liner, an AI search app with more than 10 million users across student and academic communities. "Koah lets developers monetize those moments responsibly, without compromising trust."
The Series A will primarily go toward engineering and go-to-market growth. Koah plans to expand its team, accelerate product development, and build out the fuller technology stack needed to serve both developers and advertisers at scale.
On the product side, the company is introducing analytics tools that track user engagement and ad performance inside AI search and chat environments. It is also building new context-rich ad formats designed specifically for generative AI, moving beyond what existing display or search ad formats can offer.
Koah was founded to solve a problem that didn't exist until recently. As AI chat became a primary interface for discovery and research, developers found themselves without a sustainable revenue model. The company's SDK installs in minutes and connects apps to a network of premium brand advertisers looking to reach users at the moment they are actively deciding something.
Apps like Liner, Viro, and Sup AI are already live on the platform. "Koah found a way to deliver AI-native ads that our user community actively welcomes," said Nick Arbuckle, Founder of Viro, a sustainability-focused AI app. That kind of endorsement from founders who are sensitive to user trust carries weight in this market.
Koah's core argument is that monetization and user experience don't have to be in conflict. Advertisers get access to real-time conversational context. Developers get a revenue stream that scales with usage. Users get responses informed by relevant brand expertise rather than generic display clutter.
Theory Ventures led the round, with Tomasz Tunguz bringing both financial backing and direct relevance to the problem. His background building AdSense gives him firsthand experience with what it takes to turn an ad format into infrastructure at scale. "AI apps represent a new interface layer for the internet, and they require monetization infrastructure designed for that reality," Tunguz said. "We partnered with Koah because of their team and how they're building that layer to align incentives across developers, advertisers, and users."
Forerunner and South Park Commons, both returning backers from the seed round, also participated. Together, the investor group reflects confidence not just in Koah's current traction but in the broader thesis that AI-native advertising is a category worth building from scratch.
