Phasecraft is a quantum algorithms company that designs algorithms for near-term quantum hardware, with the aim of reaching practical quantum advantage in materials simulation, chemistry, optimization and energy networks. Its algorithms are hardware-agnostic and tailored to individual quantum hardware platforms. Its product and technology work covers materials discovery, advanced biochemistry, and logistics and network optimization, and in 2025 it launched Mondrian, a quantum-enhanced software platform for optimization problems across industries.

Phasecraft was founded in 2019 as a spinout from University College London and the University of Bristol by Ashley Montanaro, Toby Cubitt and John Morton, each of whom has long experience leading quantum research teams. The company is headquartered in London, with offices in Bristol and Arlington, Virginia, and a Washington D.C. research hub led by Steve Flammia. Its team combines quantum information theorists, materials scientists, computational physicists and software engineers.

Phasecraft works with quantum hardware companies including Google Quantum AI, IBM, Quantinuum, QuEra and Atom Computing, and with end users such as Johnson Matthey, Oxford PV, the UK's National Energy System Operator and BT. It has received contracts and grants from the UK Government, UK Research and Innovation, and the U.S. Department of Energy's ARPA-E, and it joined DARPA's Quantum Benchmarking Initiative in 2026 to help estimate resource requirements for utility-scale quantum computing.

Phasecraft has raised more than $50M in venture funding and grants. Its $34M Series B in September 2025 was co-led by Plural, Playground Global and Novo Holdings' Quantum Fund, and in 2026 it announced plans to establish a U.S. headquarters in Arlington, Virginia, creating 19 jobs.