4 weeks
from brief to a working AI legal platform with three end-to-end workflows, for Stas.ai.
CTO as a Service: a fractional CTO and the senior team that ships
One monthly subscription gets your startup a named CTO who owns your architecture and roadmap, and the senior AI, backend, mobile and DevOps engineers who build it. No equity, and work starts within two weeks.
- Rated 5.0 on Clutch across 20+ verified reviews
- Products shipped for founders in Australia, Canada, Germany and the US
- PhD-led AI engineering team
Sound familiar?
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You’ve been looking for a CTO for months, and the strongest candidates keep choosing large, stable companies.
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Your technical co-founder spends the week on sales and fundraising, and the product hasn’t moved.
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You built the prototype with AI coding tools. It won the demo, and now logins, payments and edge cases break as soon as real users arrive.
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You hired one developer to do everything, and the hard parts (the AI, the data, the infrastructure) still aren’t done.
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You paid an agency or a freelancer, and nobody on your side can tell whether the code is any good.
Hiring your way out is slow and expensive. An experienced CTO in Germany costs about €12,300–13,200 a month in the first year once salary, employer social insurance and a recruiter’s fee are counted.A CTO in the UK costs about £11,300–12,100 a month in the first year once salary, employer National Insurance, pension and a recruiter’s fee are counted.A seed-stage CTO in the US costs about $20,700–23,500 a month in the first year once salary, benefits and a recruiter’s fee are counted. The search usually takes 3 to 6 months, and when the CTO arrives they still need a team.
What is CTO as a Service?
CTO as a Service from Blackthorn AI is a named fractional CTO plus a senior engineering team, on one monthly subscription. Your CTO owns the architecture and roadmap and turns your priorities into two-week sprints. The team builds them in parallel workstreams, inside your repositories and cloud accounts. You decide what comes next, see a demo at least every two weeks and get a report every month.
What you get
One contract for technology leadership and product development: one accountable technical lead, and the specialists your product needs each month.
01
A named fractional CTO
Owns your technical strategy, architecture and roadmap, turns your priorities into sprint plans and runs delivery. Can be named as your CTO in your pitch deck and joins investor meetings.
02
A senior team on demand
AI and machine learning, backend, frontend and mobile, DevOps and MLOps, data, QA and UX specialists from one senior team that works together every month, not freelancers matched per project. Your CTO brings in the right person for each piece of work, across your package’s parallel workstreams.
03
You keep the product decisions
Your side needs one product owner, often a founder, who decides what gets built next and accepts finished work. We handle the rest.
What your fractional CTO covers
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Technology strategy and roadmap
A long-term technology strategy and a 90-day roadmap tied to your business goals and next milestone: what to build, what to buy, what to keep, fix or rebuild, and which technical debt to pay down first.
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Architecture and tech stack
A scalable architecture on AWS, Azure or Google Cloud, with the data model and security sized for the next 12 months of growth.
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MVP scope and delivery
The smallest product that proves your business, planned in two-week sprints with a demo at the end of each.
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AI and machine learning
Choosing between off-the-shelf models, fine-tuning and custom models; LLM, RAG and agent design; evaluation, cost control and MLOps.
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Security, privacy and compliance
GDPR-ready data handling, access control and audit trails, and an IEC 62304-aligned process when you build medical software.
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Hiring and your existing development team
Job descriptions, technical interviews and onboarding. Your CTO can also lead your in-house or freelance developers.
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Investors and due diligence
Technical slides, Q&A preparation, investor meetings and the technical side of due diligence.
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Vendors and costs
Your CTO reviews agency proposals, SaaS tools and cloud bills before you sign.
Fast delivery, with senior review on every change
Our engineers build with the latest AI coding agents every day. The agents draft code, tests, documentation and migrations. Senior engineers set the direction, review every change and own the result. That is how a small senior team keeps the pace of a much larger one. Capacity is counted in parallel workstreams, so when the agents make us faster, you get more shipped for the same price.
7 weeks
from prototype to a pilot with early adopters, for a contactless vital-signs app in the US.
Speed doesn’t cost you control. All work lives in your repositories and cloud accounts, and our AI tools run on business terms that exclude training on your code.
How we keep our advice independent
A fair question about any CTO-as-a-Service offer: will a CTO who works with the delivery team recommend more delivery? These rules are part of every contract.
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The day-30 assessment is yours.
It is a written plan any competent team could carry out, including your own hires or another vendor.
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Your CTO can recommend less of us.
If freelancers, an off-the-shelf tool or a smaller package is the better deal, your CTO says so, and you can move down a package at the end of any term.
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No lock-in.
Code, models, infrastructure and documentation sit in your accounts from the first day, built on standard open tools.
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Your developers are welcome.
Your CTO leads in-house or freelance developers alongside ours, held to the same review standards.
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You see what you pay for.
The monthly report lists what shipped, what is in progress and what comes next. Timesheets are available when grant reporting needs them.
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We plan our own exit.
When you are ready for a full-time CTO, we write the job description, run the technical interviews and hand over.
Packages and pricing
Every package includes a named fractional CTO, a senior team, a 30-day technical assessment with a 90-day roadmap, and a monthly report to the founders. Terms are flexible: choose 3, 6 or 12 months, and move up or down a package as your needs change.
| Package detail | SDirection | M RecommendedBuild | LScale |
|---|---|---|---|
| Starting from | €5,500£5,100$6,500a month | €10,800£9,800$13,000a month | €17,800£16,100$21,900a month |
| Best for | A prototype or a small dev team that needs technical direction and extra capacity | Building or rebuilding the product without an in-house team | Live users or a funding round to deliver on |
| Fractional CTO | Weekly check-in, answers between calls, architecture and vendor decisions | Owns the roadmap, plans every sprint, sets code standards | Joins your leadership meetings and owns delivery end to end |
| Parallel workstreams | 1 | 2 | 4 |
| Delivery manager | Not included | Included | Included |
| Demos | Weekly or every two weeks | Weekly or every two weeks | Weekly or every two weeks, plus a quarterly business review |
| Replies (Mon–Fri) | Next business day | Same business day | Within 4 business hours |
| Hiring support | Not included | Job descriptions and technical interviews | Job descriptions, interviews and onboarding |
| Investor support | Review of your deck’s technical slides | Technical slides and Q&A preparation | Joins investor meetings and due diligence |
Starting prices are per month on a 12-month term, excluding VAT where it applies.
A workstream is one piece of work in progress at any time: a feature, an integration, an AI model or a fix. When it ships, the next item from your backlog starts, and you can reorder the backlog whenever you like. Your CTO splits large features into pieces that ship within days. A workstream is a unit of capacity, not one full-time engineer: your CTO brings in whichever specialists each item needs.
Book a 30-minute intro call
We’ll tell you which package fits, or whether you need us at all.
Hiring a full-time CTO, a fractional CTO or CTO as a Service
| Compared on | Hire a full-time CTO | Independent fractional CTO | Blackthorn CTO as a Service |
|---|---|---|---|
| Monthly cost, Europe | About €10,500 in salary and employer social insurance; €12,300–13,200 in year one with a recruiter’s fee | About €2,500–12,000 for a few hours to 2 days a week of CTO time; the team is extra | From €5,500, team included |
| Monthly cost, UK | About £9,600 in salary, employer NIC and pension; £11,300–12,100 in year one with a recruiter’s fee | About £3,000–7,000 for 1–2 days a week of CTO time; the team is extra | From £5,100, team included |
| Monthly cost, US | About $17,500–18,750 in salary and benefits at seed stage; $20,700–23,500 in year one with a recruiter’s fee | About $4,000–25,000 for 10–40 hours of CTO time; the team is extra | From $6,500, team included |
| Time to start | 3–6 months of executive search | Days to weeks after a match | 1–2 weeks after signing |
| First shipped work | Month 4–7 at the earliest: the search, then onboarding and hiring a team | Depends on your developers or agency; the CTO advises | From month 2, then every two weeks |
| Who manages the work | You manage the CTO; the CTO manages the team they hire | You coordinate the CTO, your developers and any agency | Your CTO, with a delivery manager on M and L; you set the priorities |
| Equity | Usually 1–3%, far more for a co-founder | Sometimes | None |
| Who builds the product | You still hire a team | You still hire a team or an agency | Included: 1–4 parallel workstreams run by a senior team |
| Skills | One person’s | One person’s | CTO plus AI/ML, backend, frontend, mobile, DevOps, data, QA and UX specialists |
| If it doesn’t work out | Notice periods, possible severance, equity and months lost | Ends quickly, and you keep a plan rather than a product | 30 days’ notice after the committed term; the code is already in your repositories |
Sources: Europe: average salary of an experienced CTO (StepStone 2026), employer social insurance at 2026 contribution ceilings, published DACH fractional CTO prices (Wavect, 2026). UK: median CTO salary of £100,000 (ITJobsWatch, six months to 9 October 2026), employer NIC and minimum pension for 2026/27 (GOV.UK, The Pensions Regulator), published fractional CTO rates (fractional.quest, September 2026). US: average cash salary of a non-founding CTO at seed stage, $190,000 (Kruze Consulting, 2024 payroll data), benefits of $20,000–35,000 a year. All regions: recruiter fees, search time, US fractional retainers and CTO equity (A.Team, 2026).
Who it’s for
and who it isn’t
A good fit
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Non-technical founders without a technical co-founder who have funding, a grant or revenue, and a product to build in the next 6–12 months.
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Clinicians, scientists, lawyers and other domain experts building AI-heavy or regulated products.
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Companies launching a software or AI product next to an existing business, without building an engineering department.
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Teams whose CTO has left, or whose prototype or agency-built product has stalled.
Not a fit
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Teams with 8 or more engineers who need a full-time technical leader every day.
Hire one; we can help you do it.
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Founders who need only a few hours of advice a month.
An independent advisor fits that budget better.
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Offers of equity instead of fees.
We work on paid subscriptions only.
How we start
Your fractional CTO
Alex Gurbych, founder and CEO of Blackthorn AI. Alex holds a PhD in AI and has 15+ years of experience in software and machine learning. He worked his way from developer to software architect and CTO, has published 20+ peer-reviewed papers on machine learning, and founded Blackthorn AI in 2021.
Work we’ve shipped
| Client | What we built | Time and team |
|---|---|---|
| Stas.ai, legal AI, Australia | AI platform for contract review, drafting and legal Q&A | 4 weeks from brief to working platform, team of 5 |
| HealthWorks Dx, healthtech MVP, Canada | AI health assistant and VR health app on Google Cloud | 5–6 months, team of 4 |
| Medical image-to-report platform, Germany | Generative AI combined with decision trees, from LLM prototype to production handover | 24 weeks, team of 6 |
| Contactless vital-signs MVP, US | Heart rate from smartphone face video, within 5 BPM of reference devices, through to a pilot | 7 weeks, team of 4 |
What founders say about working with us
Rated 5.0 across 20+ verified client reviews on Clutch.
«Delivered more than promised»
They delivered on the contract date, four weeks after kickoff.
Stanislav Roth
Founder, Stas.aiWhat impressed us the most was their ability to take over a fragile frontend in production, quickly fix a critical authentication issue, and then deliver a large UI redesign with strong QA discipline, all while keeping scope controlled and avoiding risky backend changes.
Egoitz Arruti
CTO, Ubikare
Highly recommend!
Alex and his team work fast and provide quality work because they pay attention to detail.
Jason Mitakidis
Founder at HealthWorks Dx Inc.They always delivered on time and showed 100% transparency in the project development.
Alejandro Gonzalez
Product manager, Monitoring LifeThe collaboration with Blackthorn AI was outstanding, they worked at a high pace and responsibly.
Sven Jansen
CEO at Neo-Q Quality in Imaging GmbH
«That’s a really great thing!»
Their speed and structured approach helped us move from idea to MVP without bottlenecks.
Jash Shah
Founder and CEO of MedieryWhat impressed us the most was their ability to take over a fragile frontend in production, quickly fix a critical authentication issue, and then deliver a large UI redesign with strong QA discipline, all while keeping scope controlled and avoiding risky backend changes.
Egoitz Arruti
CTO, UbikareThey always delivered on time and showed 100% transparency in the project development.
Alejandro Gonzalez
Product manager, Monitoring LifeThe collaboration with Blackthorn AI was outstanding, they worked at a high pace and responsibly.
Sven Jansen
CEO at Neo-Q Quality in Imaging GmbH
«That’s a really great thing!»
Their speed and structured approach helped us move from idea to MVP without bottlenecks.
Jash Shah
Founder and CEO of MedieryCase studies
Read the full stories
01How much does a fractional CTO cost?
In the US, independent fractional CTOs typically charge about $4,000–25,000 a month for 10–40 hours of their time (A.Team, 2026). In the UK, published day rates run about £1,000–1,600, and 1–2 days a week costs about £3,000–7,000 a month. In Germany and Austria, published retainers run from about €2,500 for a few hours to €12,000 for 1–2 days a week. In every case the team is extra. Our packages start from €5,500 a month in Europe, £5,100 in the UK and $6,500 in the Americas and Australia, and include both the CTO and 1–4 parallel workstreams run by our senior team.
02What’s the difference between a fractional CTO, an interim CTO and CTO as a Service?
A fractional CTO works part-time on an ongoing basis. An interim CTO covers the role full-time for a fixed period, usually during a search or a crisis. CTO as a Service is a fractional CTO plus the team that builds what they plan.
03Can you work with our existing developers?
Yes. Your fractional CTO can lead in-house or freelance developers alongside our team, set the roadmap and standards, and review their work.
04Will your CTO push us to buy more of your team?
No. The day-30 assessment is a plan any team can carry out, your CTO can recommend a smaller package or other people, and you can move down a package at the end of any term.
05Who owns the code?
You do. All work happens in your repositories and cloud accounts from day one.
06Can you take over a prototype built with AI coding tools?
Yes. The day-30 assessment shows which parts of the prototype can stay and what has to be rebuilt. Authentication, payments, data handling, tests and deployment are the usual gaps.
07What if we want to hire our own CTO later?
We help you do it: job description, interviews, onboarding and a clean handover.
08Is our code used to train AI models?
No. Our tools run on business terms that exclude training on your code.
09Which industries do you work with?
We work across industries. Our deepest expertise is in AI-heavy and regulated products, such as healthcare, medical devices, diagnostics, life sciences and legal technology.
10How long do we commit for?
3, 6 or 12 months, then 30 days’ notice after the committed term.
11Why don’t you sell hours?
Hourly billing rewards slow work. You pay a fixed monthly price for a number of parallel workstreams, so we gain from shipping faster, and our AI tooling turns into more shipped work for you. Timesheets are available when grant reporting needs them.
12Why do prices differ by region?
Prices follow what CTOs and engineering teams cost in each market. UK plans are invoiced in pounds, plans in the Americas and Australia in dollars, and calls are scheduled in your business hours.
13What if we need more done in a busy month?
Add a workstream for the month (€4,000 in Europe, £3,600 in the UK, $4,900 in the Americas and Australia), or move up a package.
14Can we pay with grant funding?
Some grants treat subcontracting as an eligible cost, and some national programmes fund only internal staff. We check the fit with you before you sign.
15What happens at the end of an engagement?
We hand over documentation and access, and transfer knowledge to your team. Source code, trained models and other artefacts are already in your accounts.
16Where is the team?
Led from Germany, with senior specialists across Europe, working in your time zone for meetings.
Next step: a 30-minute intro call
We look at where your product is, what’s blocking it and which package fits. No preparation needed.