Data centre AI startup Build raises £6.4m led by Index Ventures
This article covers Build, an AI startup that has raised £6.4m in a seed funding round to accelerate pre-development workflows for data centre and infrastructure projects. The funding will scale Build's agentic AI and human-review model to compress site sourcing, technical due diligence and early design timelines, supporting developers, investors and public bodies involved in data centre and infrastructure deployment.
Build, an AI startup that automates pre-development workflows for data centre and infrastructure projects, has raised £6.4m in a seed funding round to accelerate feasibility work that typically stalls early on in project pipelines. The funding will be used to scale Build’s agentic AI and human-review model that turns weeks of site sourcing, technical due diligence, power assessment and early design into outcomes delivered in hours.
Why it matters
Data centre and infrastructure development across the US and Europe is facing a bottleneck at the pre-development stage. Long, fragmented processes for site identification, connection feasibility and early technical design are delaying projects even when capital is available. That backlog has drawn policy attention: in the UK the government has introduced AI Growth Zones to speed digital infrastructure, while in the US interconnection queues now contain over a terawatt of large-load applications. Large planned investments such as OpenAI’s Project Constellation — cited at about £377.4bn ($500bn) for US AI infrastructure — illustrate the scale of capacity that must be brought online if AI deployment continues to accelerate.
Build’s pitch is relevant because shortening these front-end timelines can materially change whether projects proceed and on what schedule.
Inside the product
Build combines automated multi-agent AI workflows with senior human reviewers. Its system runs thousands of AI-driven subtasks in parallel to assess site viability, model power and grid impacts, and produce early design outputs. Every client deliverable is reviewed by experienced operators before delivery. The company positions its offering as selling outcomes rather than licensing software: customers pay for a delivered feasibility or development decision rather than tools to run themselves.
Build says it has completed more than 100 projects across 15 countries and works with public bodies on AI infrastructure planning as well as hyperscalers and institutional real estate firms. One commercial partner cited in the announcement is Tishman Speyer, a major property investor with a significant presence in London’s Victoria district.
Who are the investors?
Build’s £6.4m seed was led by Index Ventures. The investor list also includes individuals from within major technology and real estate organisations: the announcement names the CFO of OpenAI and the CTO of Blackstone among its backers. Separately, Build draws domain experts from firms such as Blackstone, Tishman Speyer, Starwood Capital and JP Morgan into its operational and advisory layers.
In the announcement, Martin Mignot, Partner at Index Ventures, said:
Build represents a new generation of AI companies focused on delivering actual work rather than improving software workflows. James and Ben have combined deep technical capability with real operational understanding of how critical infrastructure gets built. The infrastructure challenge is global and the solution has to be too.
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Founder perspective
Build was co-founded by James Stirrat-Ellis and Ben McClusky. Stirrat-Ellis is a British architect who previously worked at Heatherwick Studio on major projects including Singapore’s Changi Airport Terminal 5 and developments in London such as Coal Drops Yard. McClusky’s background is in multi-agent AI systems and reinforcement learning research. The pair relocated to New York to build the company together.
In the announcement, James Stirrat-Ellis, Co-founder & CEO at Build, said:
AI infrastructure is essential to economic growth, but we cannot keep dropping it into communities the way we have been. Deployment is only accelerating, and the old routes will not work. The UK needs agile policy on energy and planning to avoid both community opposition and the collapse of investment. Data centres can actually support new grid development and boost grid resilience in ways that will benefit the whole economy. The tools we have to make this happen are better AI to compress timelines and better design to bring communities with us. Those two things together are how this gets built.
Stirrat-Ellis frames the product as both a technical and civic tool: faster feasibility work, he argues, can make development less disruptive by aligning projects with energy and community constraints earlier.
The bigger picture
Automating the front-end of infrastructure development is not purely a technological challenge; it interacts with planning, grid policy and local engagement. Faster site assessments and clearer early designs could reduce friction with local authorities and speed permitting, but they will not remove the need for policy reform and grid investment. Build’s approach — pairing AI with senior industry expertise — targets the practical bottlenecks that cause projects to stall, rather than replacing local decision-making.
The announcement also signals investor interest in tools that unlock physical infrastructure capacity for AI and cloud demand. If Build can demonstrate consistent, regulator-friendly outcomes, that model could be applied across markets where grid constraints and planning complexity slow deployment.
This deal highlights an intersection between UK policy measures and broader European and US infrastructure pressures: improving pre-development processes is one piece of a larger effort to bring more resilient, community-aware data centre capacity online.
They've invested in Build
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