The Quantum Software Layer: Classiq, Q-CTRL and Phasecraft
Why software matters so much
Quantum hardware is advancing, but it is still noisy and small. Writing a program gate by gate is like writing a modern app in machine code. Software firms try to close that gap in three ways: make programs easier to write, make real hardware give better answers, and invent better algorithms. Our companion pages on programming tools and how a quantum program runs cover the basics. Here are three firms, each working on one of those gaps.
Classiq: write the goal, let software build the circuit
Classiq, based in Tel Aviv, describes its product as a development platform (an IDE, compiler and operating layer) that automates quantum programming. In its words, it converts high level models into optimized low level circuits and can run them on different hardware and cloud services.
The reported funding story: on May 12, 2025 the company announced a 110 million dollar Series C, which it called the largest ever for a quantum software company, bringing its reported total to 173 million dollars. Entree Capital led, with investors including Norwest, NightDragon, Hamilton Lane, HSBC and Samsung Next. The company also said customers and revenue had tripled year over year, and named enterprise users including BMW, Citi, Deloitte, Rolls-Royce, Mizuho and Toshiba. Those are company statements. Calcalist reported a later extension with SoftBank Vision Fund 2 and CDP Venture Capital, of roughly 10 to 20 million dollars, bringing the total to about 185 to 200 million; we could not confirm its date or exact size.
Why it matters: if a bank or carmaker wants to test a quantum idea, it should not need a physics PhD for each new chip. A hardware independent layer lets the same model run on different machines as they improve.
Q-CTRL: squeeze better answers from noisy machines
Q-CTRL, whose CEO is Michael Biercuk, calls its work quantum infrastructure software. Its Fire Opal product is described as performance management software that reduces errors and handles low level hardware details automatically. Fire Opal was announced at the Q2B event in December 2022 and was reported to be integrated into IBM Quantum services from December 2023.
In September 2024 Q-CTRL announced plans for native integrations with Rigetti, Oxford Quantum Circuits and Diraq, alongside IBM. The company reported improvements across benchmark algorithms such as the Quantum Fourier Transform, Grover's search and QAOA. It also reported a fivefold increase in achievable circuit width for Mitsubishi Chemical on IBM systems, and cited gains of up to a factor of a thousand in some cases. These are the company's own results, and bigger gains tend to come on smaller devices that start from a weak baseline. Our search found no newer 2025 or 2026 announcements, so check Q-CTRL's site for current products.
Why it matters: until full error correction arrives, error suppression software is one way to get more from NISQ machines. It is a bridge, and bridges are useful.
Phasecraft: better algorithms for real problems
Phasecraft is a UK company building quantum algorithms, designed to work on today's noisy hardware by mixing quantum and classical computing. They are hardware agnostic. Reported partners include Google Quantum AI, IBM, Quantinuum Ltd and QuEra, and named end users include Johnson Matthey, Oxford PV, the UK's National Energy System Operator and BT.
On September 2, 2025 it was reported to have raised a 34 million dollar Series B, co-led by Plural, Playground Global and Novo Holdings' Quantum Fund, with total funding reported above 50 million dollars including grants. The focus areas are materials simulation, drug development for genetic conditions and energy network optimization. The company claims its materials algorithms are millions of times more efficient than before; that is a claim from the company and its backers, and the coverage gave no independent verification. Phasecraft's CEO, Ashley Montanaro, said the algorithms are delivering meaningful results now.
Why it matters: the fault tolerant era depends on knowing exactly what to run. Clever algorithms can lower the number of qubits needed for a useful job, which brings the useful date closer. Read more on algorithms and materials and medicine.
How the three fit together
- Phasecraft asks: what should we compute?
- Classiq asks: how do we express and compile it cleanly?
- Q-CTRL asks: how do we get the best result from the machine in front of us?
Reading the claims with care
Software gains are measured against a baseline, and the baseline matters. Ask what was compared, on which hardware, and whether a classical computer could do the same job. See benchmarks explained and quantum advantage. Nothing here is investment advice, and these companies have no link to the QNT memecoin.
Sources and further reading
- Classiq: raises 110 million dollars (company announcement)
- Calcalist CTech: Classiq Series C extension
- The Quantum Insider: Q-CTRL expands Fire Opal integration
- SD Times: Q-CTRL Fire Opal launch
- Tech.eu: Phasecraft raises 34 million dollars
Reported as of 2026-10-09. Funding figures and performance numbers are company statements or press coverage, not audited facts. Educational overview only, not financial advice. The QNT memecoin is an independent community project and is not connected to any company named here, including Quantinuum Ltd.
Frequently asked questions
What does Classiq do?
It offers a platform that turns high level quantum models into optimized circuits that can run on different hardware, according to the company.
What is Fire Opal?
Q-CTRL's software that reduces errors and automates hardware details so users can run more complex circuits on today's devices. Gains are company reported.
What does Phasecraft focus on?
Hardware agnostic algorithms, with focus areas reported as materials simulation, drug development and energy networks.
Are the efficiency claims proven?
They are company and investor claims. Check what baseline was used and whether independent results exist.
Keep reading
- Quantum's Picks and Shovels: The Companies Behind the Machines
Every quantum computer needs control electronics, cold rooms, error correction and software. Meet the enabling-tech layer that many quantum builders rely on. - Quantum Programming Tools and SDKs Explained
What tools do people use to program quantum computers? A general guide to open source SDKs like Qiskit and Cirq, simulators, cloud access and how to choose one. - Quantum Algorithms Explained for Beginners
What is a quantum algorithm? Learn how Shor's, Grover's and other quantum algorithms work in plain English, and which ones matter for cryptography and crypto. - NISQ Explained: Noisy Intermediate-Scale Quantum Computers
What does NISQ mean? Learn why today's noisy, mid-size quantum computers are limited, what they can do, and how the field plans to move past them.
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