What CTO-as-a-service actually delivers
The phrase “fractional CTO” covers a wide spectrum, from advisory-only operators with a deck and an opinion through to engaged practitioners who write code in the same week they review the architecture. The work below is what I deliver in every engagement, regardless of cadence. Pick the rows that match the decision in front of you.
Architecture review
What you have, what it costs, what to change first.
A written architecture review of the current estate — frontend, backend, data, infrastructure, integrations, and the connective tissue between them. Includes a prioritised list of risks and remediation work, sized in engineering days. Output is a document the team can act on, not a slide deck.
Vendor and stack selection
Pick the right tool, defend the choice on a call.
Selection work for a discrete decision: cloud, database, CMS, build tooling, AI provider, observability, payments. Includes shortlist, weighted scorecard, total-cost-of-ownership view over three years, and a recommendation defensible to the board. Migrations from a wrong-fit incumbent included where in scope.
Team assessment and hiring
Right people, right roles, right interview process.
Assessment of the current engineering team against the work in flight: where are we strong, where are we thin, where is delivery actually blocked. Includes role definitions, hiring panel design, technical interview questions (real ones, not LeetCode), and reference-check templates. Coverage in interviews where useful.
Board and investor technical communication
Translate engineering reality into decisions the board can act on.
Slide-deck contributions, written technical sections for board packs, and Q&A backstop for board meetings. Risk-register input around technical debt, security posture, and key-person dependencies. Aimed at board members who are not engineers but need accurate technical context to vote.
Technical due diligence
A defensible report inside 30 days.
Technical due diligence on a target company for an investment decision — code, architecture, team, security, key-person risk, IP integrity, third-party dependencies, and integration debt. Output is a written report with a clear go / no-go recommendation and a ranked list of post-deal work. Suitable for use under Series A–B diligence conventions.
Most engagements combine three of the five rows above. The mix is set in week one and revisited at each quarter.
When fractional is the right answer
A fractional CTO is the right call when the technical decisions exceed what your founding engineer can absorb solo, but a full-time CTO is too expensive or too senior to attract at your stage. Below is a five-row matrix to test against your own situation.
| Trigger | Symptom | Why fractional fits |
|---|---|---|
| Pre-Series A architecture lock-in | The team is making 10-year choices on stack, hosting, and data with two years’ experience between them | Senior input at the moment the choice is reversible, then step back |
| Post-funding scale | New money to spend, no senior engineering operator to spend it well | Hiring panel, role design, and architecture roadmap before the first three hires land |
| Critical migration | Drupal 7 EOL, monolith-to-services, on-prem to cloud — decisions that will burn weeks if got wrong | A practitioner who has run the same migration before and writes the rollout plan |
| Board / investor pressure | Board wants quarterly technical visibility; investors want due-diligence-grade artefacts | Written communication into board packs, Q&A backstop in meetings |
| Single-engineer key-person risk | One person knows everything, holidays are stressful, illness is existential | Architecture documented, hiring kicked off, second engineer onboarded under structured handover |
A common pattern is “two of the five at once” — a critical migration during post-funding scale, or board pressure that exposes single-engineer key-person risk. The fractional model handles those overlaps because the engagement is shaped to the work, not to a job description. The wrong call is paying advisor rates for an advisor when the team needs an operator.
When fractional is the wrong call
Three situations where I would steer you away from a fractional model:
- The role is full-time. If the team genuinely needs daily senior leadership and the budget supports a £150k–£200k hire, take the hire and run a board-led search.
- The decision is reversible. If the question is “what payment provider do we use”, a half-day with a senior engineer beats an ongoing retainer.
- The motivation is signalling. If the goal is “we have a CTO” on a pitch deck without the work to do, the engagement will under-deliver against the expectation. Tell investors the truth.
What it costs
Pricing is published, not negotiated by attrition. The figures below are the floor of the engagement; specific shape (days, deliverables, term length) is set after a 30-minute scoping call. No retainer commitment beyond the first month.
From £1,000 / day
For project-led work — architecture review, vendor selection, technical due diligence, or any defined-scope deliverable. Billed per day worked, invoiced monthly. UK and EU clients only. VAT additional.
From £3,000 / month
For ongoing fractional engagements — typically three to five days a month covering strategy, architecture, hiring, and board comms. Three-month minimum term. Termination notice: 30 days after the minimum.
Bespoke
For interim Technical Director cover, full-time during a transition, or engagements spanning two service lines (e.g. CTO + AI build). Priced on scope. Always cheaper than reactive hiring; almost always cheaper than the wrong technology decision.
Why the floors and not exact figures: the right number depends on cadence, sector, term length, and where the work sits on the strategy-to-delivery axis. Regulated-industry engagements (pharma, healthcare, financial services, NHS suppliers) carry a premium because the compliance overhead is real. Pre-revenue startups occasionally land discounted retainers in exchange for a longer term commitment. Talk to me about the work and the number lands fast.
Want a number for your specific shape? → Talk to me
Track record
The shortlist of named clients below covers fifteen years of in-house team and consulting work across UK enterprise, charity, life-sciences research, and broadcast media. The roles changed over that period — from senior developer to Technical Director to Drupal Architect — but the constant has been the same: senior, hands-on, close to the code, accountable to a delivery date.
Cancer Research UK
Senior Drupal architecture and delivery for the UK’s largest cancer research charity, via Catch Digital between 2015 and 2019 (Technical Director at Catch Digital). Multi-site publishing platform, performance work on traffic peaks around fundraising campaigns, integration with the donation back-end. The work demanded a charity’s blend of cost discipline and editorial independence. Successful delivery with no production incidents over the four-year window.
The Francis Crick Institute
Senior Drupal delivery for the Francis Crick Institute, the largest biomedical research institute under one roof in Europe, via Catch Digital. Long-form research-content publishing platform, public-facing scientific communication, accessibility to WCAG 2.1 AA. Coordinated with internal communications, science writers, and the Crick’s IT estate. The site is still in production at the time of writing, with Drupal version upgrades carried through subsequent agency engagements.
BBC Studios — including BBC Good Food
Senior Drupal and PHP work for BBC Studios, including the BBC Good Food platform, via Catch Digital. High-traffic editorial site, performance-critical recipe and content rendering, integration with the wider BBC editorial CMS estate. Worked alongside in-house BBC engineering and editorial teams on production deploys. The platform serves several million monthly visitors and is still operational under continued in-house development.
Foundry Visionmongers — Nuke and Katana
Senior PHP and integrations work for Foundry Visionmongers, the company behind Nuke and Katana — the visual-effects compositing tools used on most major film and television productions. Marketing site, licensing flow, customer portal integrations. Different sector, same engineering disciplines. Delivery via Catch Digital, with direct access to Foundry’s product and marketing teams.
Enovation Solutions — open-social Drupal distributions
Senior Drupal Architect at Enovation Solutions in Dublin (2020–2024), delivering custom Drupal distributions built on Open Social and integrated with Moodle LMS for international clients including Transitions Lenses (US, optical), the International AIDS Society (IAS) (global health, Geneva-headquartered), the Gaelic Athletic Association (GAA) (Ireland’s largest sporting organisation), and EASL — the Home of Hepatology (European Association for the Study of the Liver). Architecture, integrations, and senior delivery against member-platform and learning-platform requirements.
A note on framing: those engagements were delivered in cooperation with Enovation Solutions (2020–2024), where I held a senior role. They are not direct contracts of Turczynski Interactive Ltd — and that distinction matters when verifying credentials. The depth of the work is the same; the legal entity at the time of delivery is on the CV.
Current direct engagements
Current direct engagements through Turczynski Interactive Ltd include Sedno — an AI-powered symptom-journal mobile app approved by both the Apple App Store and Google Play, and the source of the production-RAG case study referenced below.
Practitioner, not pundit
Most fractional CTOs talk about AI; few have shipped one. The point of having a CTO is to get advice from someone who has done the work — not someone who has read about the work. Below is the proof, from a current direct engagement.
Sedno — your symptoms have a story
Sedno is an AI-powered symptom-journal mobile app I lead the engineering for. It helps people track symptoms over time and surface patterns ahead of clinical appointments, grounded in a curated retrieval-augmented architecture rather than a raw LLM. The application is approved by both the Apple App Store and Google Play; public release is imminent at the time of writing.
Architecture in summary: Flutter mobile client (single codebase shipping both iOS and Android), ASP.NET Core back-end hosted in the EU, pgvector retrieval over curated source literature, tiered Anthropic Claude calls (two models picked per task by complexity), a separate embedding model for retrieval, RevenueCat for store subscriptions, evaluation harness gating retrieval-quality regressions before they reach users.
I write more about Sedno on the AI / RAG service page. The reason it sits inside the CTO pillar is that production-AI experience is the moat for senior technology leadership in 2026 — and the only credible way to demonstrate it is to ship one.
Regulated industry — pharma, healthcare, financial services
Regulated-industry experience is the underrated credential. Most senior consultants come from agency or pure startup backgrounds. I work day-to-day at MSD Animal Health on enterprise C# systems and MSSQL data platforms — and that current pharma-sector employment translates directly to engagements with NHS suppliers, life-sciences scale-ups, and HMRC-style compliance work.
Why it matters: regulated-industry buyers screen for it. A team building a healthtech product wants a senior advisor who has read a Data Protection Impact Assessment, not someone who has only read about one. A scale-up navigating MHRA approval wants someone who has navigated equivalent reviews before. A PE firm doing diligence on a regulated target wants a reviewer who knows what auditable retrieval traces look like in practice.
The translation is straightforward. The disciplines that pay off in pharma — change management, audit trail, validation, evidence — are the same disciplines that pay off in any organisation where engineering decisions have downstream legal or clinical consequences. If your sector has a regulator that can shut you down, the rigour transfers.
I do not currently take engagements in domains where my MSD employment would create a conflict of interest (animal health products and direct competitors). Anything else is in scope.
How to evaluate me — and any fractional CTO
Use this section as a checklist when comparing candidates. The questions are deliberately specific — generic questions yield generic answers. Most of these can be tested in a 30-minute working call. If a candidate flinches at any of the verification asks below, treat that as data.
- Named clients you can verify. Ask for clients you can look up independently. The section above lists Cancer Research UK, the Francis Crick Institute, BBC Studios, and Foundry Visionmongers (all delivered through Catch Digital), plus Transitions Lenses, the International AIDS Society, the Gaelic Athletic Association, and EASL (delivered through Enovation Solutions). Both consultancies are still operating and can verify the engagements.
- Shipped production work. Ask to see something running, not something planned. Sedno is on the App Store and Google Play; my Drupal contributions are at drupal.org/u/Turek; my GitHub is github.com/Turek.
- Recent code commits. Ask when the candidate last shipped a pull request to a real codebase. Senior consultants who haven’t committed code in three years drift fast on stack reality. My commit graph is public.
- References from non-CTO engineers. CTO-to-CTO references are usually sympathetic. Ask to talk to a senior engineer, an SRE, or a tech lead who worked with the candidate day-to-day. The view from the trenches is the one that matters.
- Architecture-diagram reading test. In a 30-minute call, share a real architecture diagram from your stack and ask the candidate to read it back. The depth of the questions tells you everything. Reading diagrams is harder than drawing them.
- Written scope before kick-off. Insist on a written engagement scope — deliverables, cadence, term, and exit criteria — before signing anything. A consultant who resists scope on day one is a consultant who will resist it on day ninety.
- Conflict-of-interest disclosure. Ask for the candidate’s current book of clients (anonymised if necessary) and any sectors they will not take work in. Reputable practitioners disclose without prompting.
Run the seven questions above on me and three other candidates → Talk to me
How an engagement works
Every engagement starts with a 30-minute scoping call followed by a written proposal. The shape below is the default — adjust each layer to the work in front of you. There is no minimum engagement length beyond a fair month-one investment to get into the work.
Week 0 — discovery. A 30-minute call to understand the situation, the people, and the constraints. Free, no preparation required from your side. If the engagement isn’t right for either of us, I’ll tell you.
Week 1 — kickoff. Read the existing estate. Sit in on a stand-up and a planning session. Meet the founding engineer and any senior technical leads. Output: a one-page note with my reading of where the team is, where the work is, and the proposed shape of the engagement (cadence, deliverables, first-month focus).
Weeks 2–4 — depth. Architecture review, hiring kickoff, vendor work, or whichever of the deliverables fits. Weekly written update — three lines on what shipped, what’s in flight, what’s blocked. No slide decks unless an external audience needs one.
Month 2 onwards — cadence. Settle into the working rhythm. Quarterly review of the engagement — what’s working, what to drop, what to bring forward. Termination notice 30 days; no penalty.
Termination and handover. If we wind down — whether after three months or three years — handover is in scope and unbilled. Architecture documented, decisions logged, hiring panels briefed. The team carries on without me.
Cadence preference: weekly show-and-tell, written updates over verbal, decisions made in the open so the team and the board see the same thing at the same time.
Frequently asked questions
What does a fractional CTO do for a startup?
A fractional CTO provides senior technology leadership part-time — typically 1–3 days a week. They set technical strategy, assess teams, select vendors, unblock architecture decisions, and translate engineering for boards and investors. For a startup, that means seasoned-CTO judgement at roughly 40–50% of the cost of a full-time hire.
How much does a fractional CTO cost in the UK?
UK fractional CTO day rates typically run £900–£1,600 depending on seniority, sector, and engagement length. Monthly retainers usually fall between £3,000 and £7,500 for 3–5 days a month. London-based senior practitioners with named enterprise clients sit at the upper end of the range.
What is the difference between a fractional CTO and an interim CTO?
A fractional CTO works part-time on an ongoing basis — typically a small number of days a week or month. An interim CTO works full-time for a defined window, usually covering a vacancy, a transition, or a specific transformation. The skills overlap; the cadence and contract shape differ.
When should a startup hire a fractional CTO?
Hire one when the technical decisions exceed what the founding engineer can absorb solo, but a full-time CTO is too expensive or too senior to attract at the current stage. Common triggers: pre-Series A architecture choices, post-funding scale-up, a critical migration, or board-level technical communication needs.
How many hours per week does a fractional CTO work?
Most fractional CTO engagements run between one and three days a week. Some are billed monthly — three to five days a month for advisory work, more for active delivery. The right cadence is set by the work, not by a default. A weekly show-and-tell beats a quarterly review at every cadence.
Can a fractional CTO work across multiple companies at once?
Yes — that is the model. A fractional CTO typically holds two to four engagements simultaneously, capped to protect attention and avoid conflict-of-interest. Reputable practitioners disclose their book of work and use written agreements to manage IP, confidentiality, and sector exclusivity where it matters.
What does a fractional CTO charge per day in London?
London day rates for senior fractional CTOs range from about £1,000 to £1,600. Mid-market practitioners sit at £900–£1,200. The upper end applies to consultants with named enterprise clients, regulated-industry experience, or shipped production AI to back the strategic advice.
How do I find a fractional CTO in the UK?
Most UK fractional CTOs are found through three channels: direct referral from a peer founder or investor, marketplace platforms (Clutch, fractional.quest, redeagle.tech), and inbound from a consultant’s own site and LinkedIn presence. The first channel almost always produces the best fit; the others widen the funnel.
Is a fractional CTO worth it for a small business?
Yes, when the alternative is leaving senior technical decisions unowned. A small business with a single in-house engineer often gains more from one day a week of fractional CTO time than from hiring a second junior. The ROI sits in avoided rework, vendor-cost discipline, and faster, fewer wrong turns.
What is CTO-as-a-Service (CTOaaS)?
CTO-as-a-Service is the productised packaging of fractional CTO work — usually a fixed monthly retainer covering a set number of days, defined deliverables, and a standard contract. It removes negotiation friction for buyers and gives the CTO a predictable income shape. The output is the same as a tailored engagement.
How do I evaluate a fractional CTO before hiring?
Look for: named clients (in-house or consulting), shipped products you can verify, a recent code commit history, references from non-CTO engineering leaders, and a clear written scope. Test for hands-on depth in a 30-minute working call — ask them to read a real architecture diagram, not just talk about strategy.
What is the difference between a fractional CTO and a technical director?
A Technical Director typically reports inside an organisation, manages a team, and owns delivery. A fractional CTO sits at strategy and architecture level, often without line management. In practice the roles blur — many fractional CTOs cover interim Technical Director duties when the team needs steady senior leadership through a transition.