Fractional CTO Services in London
The best Fractional CTO Services in London, at the best available price.
You have engineers, or contractors, or an agency, and no one whose job is to decide whether the architecture, the spend and the hiring plan are right. That is the gap: ten to twenty hours a month from someone who has built and run the thing you are building, and who will tell you when you are about to spend money you do not need to.
London is Europe's largest technology and finance hub, with fintech, AI labs, insurers and banks concentrated in one city. Buyers are sophisticated and well funded, and almost every serious one asks early where data is processed and how AI decisions can be explained.
London scale-ups often need senior technical leadership between their founding engineer and a full-time CTO hire. A fractional CTO covers that period.
What you get
- Architecture decisions made and written down, with the trade-offs stated rather than assumed
- Infrastructure and AI spend reviewed against what you actually use, not what you provisioned
- Hiring: what roles you need next, what to test for, and which hires to delay
- A technical voice in investor and customer conversations when you need one
- Honest counsel on build versus buy, including when the answer is to buy
Scoped to the hours you actually need. Month to month, with no long lock-in, because a fractional CTO you cannot leave is just an expensive employee.
Invoiced in USD or GBP, payable by Wise or bank transfer.
Request a callback
You speak to the engineer who does the work. No sales rep, no deck.
Who builds here
AI Development Company
London has more demand for AI product work than almost anywhere in Europe, and most of it has to hold up in front of regulated customers, which is the kind of AI engineering we do.
What London companies build with us
Get it built at $0.
That is not a discount. It is when you pay. The work is split into checkpoints with acceptance criteria written down before anything starts, and each checkpoint is invoiced only after you have seen it and accepted it. No deposit.
- $0 to start
- You hold every dollar until a checkpoint is delivered and you accept it. No approval, no invoice.
- Fixed cost, unlimited features
- Or hire the team outright: one fixed monthly cost, unlimited feature development, any stack.
- The engineer takes your call
- The person on your first call is the one who architects and writes it. No account managers, no bench time.
A US agency quotes $50,000 to $150,000 for the same build and asks for 40 to 50% of it before a line is written. Account managers, project managers, sales commission and bench time. None of it appears in your product.
Three stages, nothing hidden.
Twenty-minute call
We work out whether you need a fractional CTO at all. Plenty of teams need one good senior engineer instead, and that is a cheaper answer worth hearing.
First month, diagnostic
Architecture, infrastructure spend, delivery process and team shape reviewed, with the findings written down plainly and prioritised by what they cost you.
Ongoing retainer
A fixed block of hours each month. Regular reviews, decisions when they are needed, and direct access rather than a ticket queue.
What actually applies here.
Regulation and data
UK GDPR and the Data Protection Act 2018 govern personal data, and the Data (Use and Access) Act 2025 relaxes some rules on automated decision-making while keeping safeguards such as the right to human review of significant decisions. Financial firms answer to the FCA, whose Consumer Duty and operational resilience rules shape what they can outsource and how AI outcomes are monitored. The UK has no single AI statute; regulators apply their existing rules to AI.
Contracting and payment
You contract with an individual consultant based in India, not a UK company. Invoices can be issued in GBP or USD and paid by Wise or bank transfer. Your accountant will treat an overseas supplier in the usual way; any paperwork they need is provided before work begins.
Working hours
Full UK working-day overlap. Calls at whatever hour suits your team, and no waiting a day for an answer.
Can data stay in the UK?
Yes. We deploy into UK regions of your own cloud account, and models can run there as well, so personal data stays in the UK.
Can you work with FCA-regulated firms?
Yes. That means following your outsourcing and operational resilience requirements, keeping audit trails and making sure AI outcomes can be monitored and explained, all documented for your compliance team.
Do we actually need a fractional CTO?
Often not, and you will be told so. If the real problem is that nobody is building fast enough, a senior engineer is a better spend. A fractional CTO earns its cost when the expensive decisions are the bottleneck: architecture, infrastructure spend, build versus buy, and who to hire next.
How is this different from an advisor?
An advisor gives opinions. This role makes decisions, writes them down, and is accountable for them. Where it helps, the work is done rather than delegated, including the parts that involve opening the codebase.
What happens to our existing team?
They keep building. The role is to remove the decisions that block them and to be honest with you about where the team is short, which is usually a smaller gap than founders fear.
Fractional CTO
Senior technical leadership, 10-20 hrs/month: architecture, AI strategy, cost control.