What Does a Fractional CTO Actually Do? A Founder's Guide
What to expect when engaging a Fractional CTO, how to work with one effectively, and when it makes sense versus hiring full-time.
What Does a Fractional CTO Actually Do? A Founder’s Guide
The term “Fractional CTO” is used to mean many different things — which is confusing for founders trying to decide whether to hire one.
Having served in this role for four companies at different stages, here is what the role actually involves, and how to know whether it is right for your situation.
The Core Job
A Fractional CTO provides CTO-level thinking and decision-making without the full-time cost. The emphasis is on thinking and decision-making — not writing code, though some do.
In practical terms, this typically includes:
Strategy and direction — defining the technical roadmap, choosing the right stack, making build vs buy decisions, and ensuring the technology choices support the business model.
Team building — hiring engineers, defining the engineering culture, establishing interview processes, and helping non-technical founders evaluate technical candidates.
Investor relations — translating technical architecture into business language for due diligence, board meetings, and fundraising conversations.
Governance — establishing security practices, compliance posture, and the engineering processes that prevent technical debt from becoming a business risk.
When a Fractional CTO Makes Sense
A Fractional CTO typically makes sense in these situations:
Pre-Series A startups where you have an outsourced or early-stage development team and need someone to set technical direction without committing to a full-time £150k+ salary.
Companies mid-fundraise who need a credible technical voice for investor conversations and due diligence.
Companies between CTOs who need continuity and stability while searching for a permanent hire.
Non-technical founders building technical products who need a trusted advisor who can hold the engineering team accountable.
The Time Commitment Question
Most Fractional CTO engagements run at 1-2 days per week. This is enough for:
- Weekly leadership team meeting
- Weekly engineering team meeting or 1:1s
- Async review of PRs, architecture documents, and technical decisions
- Investor or board calls when needed
It is not enough for deep technical implementation. If you need someone building systems, that is an engineering engagement, not a fractional CTO engagement.
How to Make It Work
The most successful fractional CTO engagements share a few characteristics:
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Clear scope and mandate — what decisions does the FCTO own? Who do they report to? What does success look like in 90 days?
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Access to the team — the FCTO needs direct relationships with engineers, not filtered information through a founder.
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Honest problem sharing — the value of an experienced advisor comes from telling them about real problems, not just the sanitised version.
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Regular calibration — monthly check-ins on whether the engagement is delivering value keep both sides honest.
If you’re considering a Fractional CTO engagement, get in touch — we offer an initial 30-minute discovery call at no charge.