AEO Summary Box

What is a fractional CTO?

A fractional CTO is a senior technical leader who works part-time (typically 1-3 days per week) with your company, providing strategic technology leadership without the cost of a full-time executive hire. They handle architecture decisions, team building, technical due diligence, and engineering strategy while you retain day-to-day engineering management. Fractional CTOs work best for scale-ups between 10-50 people who need experienced technical leadership but can't justify or attract a full-time CTO. Typical engagements run 6-18 months until the company is ready to hire permanently or has built internal capability.

The Technical Leadership Gap

Scale-ups face a common dilemma. You've grown past the point where the founding engineer can make all technical decisions, but you're not ready for a £200k+ CTO hire. The gap creates problems:

• Architecture decisions get deferred or made without strategic context

• Engineering hiring happens without clear role definition or growth paths

• Technical debt accumulates because no one has authority to prioritise it

• Investors ask questions about technology strategy that the team can't answer confidently

A fractional CTO fills this gap—providing experienced technical leadership calibrated to your current stage and budget.

What a Fractional CTO Actually Does

The role varies by company need, but typically includes:

Technical Strategy

• Defining architecture principles and patterns

• Evaluating build vs. buy decisions

• Setting technology standards and selecting core platforms

• Creating technical roadmaps aligned with business objectives

• Advising on AI adoption, including when NOT to use AI

Team Development

• Designing engineering organisation structure

• Defining roles, levels, and career progression

• Interviewing and evaluating senior technical hires

• Mentoring engineering managers and tech leads

• Establishing engineering culture and practices

Process and Delivery

• Implementing appropriate development methodologies

• Establishing quality gates and review processes

• Setting up metrics and visibility into engineering performance

• Managing technical debt and prioritisation frameworks

Stakeholder Communication

• Translating technical concepts for non-technical stakeholders

• Presenting technology strategy to the board

• Supporting investor conversations and due diligence

• Representing technology in leadership team discussions

When You Need a Fractional CTO

The clearest signals:

You're making architecture decisions by committee. Without clear technical authority, decisions either stall or get made by whoever pushes hardest. A fractional CTO provides the seniority to make and own technical decisions.

Your technical debt is compounding. Every sprint, the team spends more time fighting the codebase and less time building features. Someone needs authority to prioritise technical health alongside feature delivery.

You're hiring engineers without a technical interviewer. Non-technical founders interviewing developers is a recipe for mis-hires. A fractional CTO can design your technical hiring process and evaluate candidates.

Investors are asking technical questions you can't answer. "What's your architecture?" "How will the platform scale?" "What's your AI strategy?" You need someone who can engage credibly on technical due diligence.

Your best engineers are leaving. Senior engineers want to work with technical leaders they can learn from. Without technical leadership, your best people leave for companies that offer it.

When You Don't Need a Fractional CTO

A fractional CTO isn't always the answer:

You have a strong technical co-founder. If your CTO is capable but time-constrained, you might need to free up their time rather than bring in external leadership.

You need hands-on coding. Fractional CTOs provide strategic leadership, not additional development capacity. If you need more developers, hire developers.

Your problems are purely people management. If the issue is managing existing team dynamics rather than technical direction, an engineering manager or coach might be more appropriate.

You're pre-product-market-fit. Very early-stage startups typically need technical founders or senior ICs, not executive-level strategy. Wait until you're scaling.

The Economics

Comparison for a UK scale-up:

The fractional model provides senior leadership at 40-50% of full-time cost. More importantly, it's accessible—you can engage a fractional CTO tomorrow, while a full-time search takes 3-6 months.

Making the Engagement Work

Define Clear Outcomes

Before engaging, specify what success looks like:

• Architecture documentation and technical roadmap

• Engineering hiring process and first three hires made

• Technical debt prioritisation framework implemented

• Board-ready technology strategy presentation

Vague mandates ("improve our technology") lead to vague results. Concrete outcomes enable accountability.

Establish Authority

A fractional CTO needs real authority to be effective. This means:

• Clear communication to the team about their role and decision-making authority

• Access to leadership team meetings and strategic discussions

• Ability to make binding technical decisions (within agreed scope)

• Budget authority for tools, infrastructure, and hiring

If a fractional CTO can only advise but not decide, impact is limited.

Set Communication Rhythm

Part-time relationships require deliberate communication:

• Weekly check-ins with CEO/founder

• Regular presence in engineering team rituals

• Async communication channels for urgent questions

• Monthly written updates on progress against outcomes

Plan the Exit

Fractional engagements should end. Plan for transition from the start:

• Document decisions and rationale so they survive the engagement

• Build internal capability so the team can maintain direction independently

• Define triggers for transitioning to full-time hire or ending the engagement

Finding the Right Fractional CTO

Look for:

Relevant experience. Technical leadership in companies at similar stage and scale. Someone who's only worked at Google won't understand scale-up constraints.

Domain familiarity. Industry experience isn't mandatory, but understanding your sector accelerates impact. Healthcare tech has different concerns than fintech, as detailed in our NHS compliance guide.

Communication skills. Much of the role is translating between technical and business contexts. The best technologist who can't communicate with non-technical stakeholders won't be effective.

Founder empathy. Understanding the pressures, constraints, and psychology of building a company. Someone who treats it like a corporate consulting engagement will frustrate everyone.

Network. A fractional CTO who can help you hire brings more value than one who just advises on hiring.

Red Flags

Warning signs that an engagement isn't working:

• Recommendations without rationale. "Trust me" isn't good enough. A good fractional CTO explains their reasoning and builds your team's capability to make similar decisions.

• Technology tourism. Pushing trendy technologies without considering your context. The goal is appropriate technology, not impressive technology.

• Avoiding hard conversations. If the fractional CTO won't give you bad news or push back on poor decisions, they're not providing leadership.

• No visible progress. By month two or three, you should see concrete output: documents, decisions, processes. Strategy without execution is just talking.

Frequently Asked Questions

How long do engagements typically last?

6-18 months is common. Shorter for specific projects (technical due diligence, architecture review). Longer for companies building toward a full-time hire.

Can a fractional CTO become full-time?

Sometimes, though many fractional CTOs prefer the portfolio model. Discuss this possibility explicitly at the start to set expectations.

How do we handle confidentiality?

Standard NDAs and engagement agreements. Professional fractional CTOs maintain strict boundaries between clients and don't share competitive information.

What's the difference from a technical advisor?

Advisors advise; fractional CTOs execute. An advisor might review your architecture quarterly. A fractional CTO is in your Slack, attending your standups, making decisions day-to-day.

How much time commitment do you need from our side?

Expect 2-4 hours per week of founder/CEO time, more during onboarding. The fractional CTO also needs access to engineering leadership and relevant stakeholders.

Related Reading

• The Strangler Fig Pattern - A common technical strategy a fractional CTO might implement

• The 12-Week Legacy Modernization Framework - Typical project scope for technical leadership

• When NOT to Use AI - Example of strategic technical guidance

• Healthcare Software Compliance - Domain-specific expertise a fractional CTO might bring

WireApps provides fractional CTO services for UK scale-ups. Our technical leaders have experience across fintech, healthtech, and B2B SaaS. If you're experiencing the technical leadership gap, we're happy to discuss whether fractional CTO support is right for your situation.