Hardware Design AI Platform Flow Engineering Raises $50M at $750M Valuation

AI has already cut software development’s iteration cycle from weeks to hours. Hardware is different: a single design change ripples across mechanical, electrical, and software systems at once, and every ripple has to be checked against millions of requirements and regulatory standards. Today’s hardware systems have grown so complex that this integration and verification work can no longer be done by hand.

Flow Engineering said it has raised $50 million in a Series B at a $750 million valuation. The round was co-led by Antonio Gracias, an early Tesla investor and founder of Valor Equity Partners, and Gavin Baker of Atreides Management, an early backer of Nvidia, Tesla, xAI, and SpaceX. Sequoia Capital, which led Flow’s Series A, returned, alongside Human Capital, Evantic, SV Angel, Odyssey, and EQT. Hugging Face co-founder Thomas Wolf, Mercedes-Benz CIO Jonas von Malottki, and Formula 1 champion Nico Rosberg invested personally. Roelof Botha, formerly of Sequoia, joined Flow’s board as an independent director and invested as well.

Flow builds a living system of record that ties together requirements, CAD, simulation, code, and test. On top of it, AI agents continuously track design changes, propagate their downstream impact across teams, and re-verify requirements and test coverage in seconds. The goal is the same shift software went through: compressing hardware iteration cycles from months to days. “Every hardware company now has to decide how fast it will adopt AI, and those that move first will win their markets,” said Pari Singh, founder and CEO. “Flow has emerged as the de facto platform for agentic hardware — 96% of our customers come to us inbound, and the category leaders in space, automotive, defense, and energy are now built on Flow.”

Singh’s own path led directly here. He studied mechanical engineering at Imperial College London, where he worked on hybrid rocket engine design, then went on to BAE Systems and BP, watching billion-dollar programs still get coordinated over spreadsheets. In 2016 he started a rocket-engine design consultancy, The Engineering Company, and built an internal tool linking requirements, MATLAB models, CAD, and simulation into a single feedback loop — work that typically took a design consultancy 12 weeks took 2.5 hours with the tool. That was the moment he realized the tool, not the consulting, was the real business. He pivoted to software in 2019 and formally launched Flow Engineering in 2023, opening a private beta that February.

Customer adoption has accelerated since the $23 million Series A Sequoia led last October. General Motors PPU, the Rivian-Volkswagen joint venture RV Tech, Anduril, Stoke Space, Intuitive Machines, and Pacific Fusion have all joined as customers, alongside existing users Rivian, Joby Aviation, Astranis, and Radiant Industries, which already run Flow as their default hardware platform. Adoption at Rivian in particular has spread fast, growing from 40 to 1,500 users in seven months, with engineers now running millions of API calls a week. “We evaluated 30 tools and nothing came close to Flow,” said Scott Mackenzie, Rivian’s Director of Product Development, Process & Tools. “It allows Rivian to develop faster, safer, and better by bringing a collaborative approach to systems engineering.”

The new capital funds an “AI harness” — infrastructure that lets frontier models work securely with sensitive engineering data on live hardware programs. Flow will also expand its review, branching, and evaluation capabilities and the controls increasingly complex programs require, grow its AI and systems engineering teams, and pursue FedRAMP authorization for customers in regulated industries.

Flow isn’t alone in trying to bring AI to hardware design. The incumbent market is dominated by heavyweight PLM (product lifecycle management) systems — Siemens Teamcenter, PTC Windchill, and Dassault Systèmes’ ENOVIA — none of which were built AI-native, and all of which typically take months to deploy. A newer crop of AI-native alternatives is emerging for hardware startups: Propel pitches “agentic AI” on top of a unified “product thread,” while Duro offers a programmable environment built for modern hardware teams. Earlier-stage entrants are showing up too, like Navier, which raised a $5.6 million seed earlier this year to build “autonomous engineering teams” for hardware design.