Saas Firm StackOne Raises £17m Series A Funding Led by Google Ventures

London-based SaaS start-up StackOne raised £17 million ($20 million) in its Series A funding round to further its mission to better integrate AI agents into the operations of companies around the world.

The money will be used to invest in the large language model (LLM) developed by the firm, as well as boost research and development that will enable the amount of integrations to be increased.

Led by Google Ventures, the Series A round also saw the involvement of a number of existing investors including Episode 1 and Playfair. Deepmind, Microsoft and OpenAI invested in this round.

“StackOne doesn’t just reinvent how integration platforms can and should be built – with depth, accuracy and security by default – but we believe AI agents are the missing piece in finally delivering enterprise-grade integrations at scale,” said Romain Sestier, co-founder and CEO, StackOne. “It’s the platform we’d always dreamed of, built for the AI future of SaaS, and it’s a vision shared by the whole team.”

By joining together an AI agent and a real-time engine, StackOne hopes to give team members the right level of speed and reliability that is needed to connect AI agents to SaaS. This mission is personal for the company founders, Romain Sestier and Guillaume Lebedel, as they faced the challenges of successful integrations first-hand.

“We’d see teams burn months rebuilding or refusing requests, and nothing on the market eased this pain,” said Sestier. “So we, alongside a super talented and passionate team, built it ourselves.”

For Luna Schmid, partner at Google Ventures, the ambition and clarity of StackOne is what impressed her the most, with it being clear that the pair are not simply building just another SaaS integration platform.

“They’re creating infrastructure that modern software and the entire AI agent ecosystem can rely on. The depth of secure integrations, the pace of delivery, and the team’s foresight into AI’s future uniquely position StackOne to redefine this category.”

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