Fractional CTO Jobs UK · outside IR35 · 48-hour shortlist

Hire a fractional CTO
UK in 48 hours.

Hire a fractional CTO — senior technical leadership, 1–3 days a week — for startups scaling, enterprises transforming, and teams needing strategic tech direction. UK-wide, outside IR35, shortlist in 48 hours.

£1,400 median day rate2 days typical cadenceOutside IR35Portfolio · part-time CTO
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scanning CTO mandates…
avg match time48h
£1.40k
Median CTO day rate
FACTS.md row 17
48h
Avg brief to shortlist
Quest target
2d
Typical weekly cadence
FACTS.md row 54
87
UK market data points
ITJobsWatch 2024
component · definition stepper
01 / the model

What are fractional CTO jobs?

Fractional CTO jobs are part-time chief technology roles where you own the tech strategy within a defined scope — not a consultant, not an advisor. Four ideas define the model.

01 · cadence

A chief technology officer, 1–3 days a week.

Senior, proven CTO capability across a defined slice of the week. You get the technical leadership you need without a full-time salary or a five-day commitment.

2 daystypical cadence
02 · role

Owns the tech strategy — not just advising.

Unlike a consultant or advisor, a fractional CTO is the technology leader: owns architecture, leads the engineering team, and makes the technical decisions.

FullCTO accountability
03 · structure

Structured correctly from day one.

Engagements are built outside IR35 by default — right of substitution, no mutuality of obligation, contractor-controlled working. CEST-tested.

OutsideIR35 by default
04 · horizon

A mandate, not a tenure.

Scoped to an outcome — a platform rebuild, a scale transformation, a tech debt reduction — typically 12–24 months, often with a clean handover to a permanent CTO.

1 monthnotice, not six
component · delivery quad
02 / scope

What a fractional CTO delivers.

Accountable for technology strategy and architecture — and answerable to the CEO and board, exactly like a permanent chief technology officer.

01 / ARCHITECTURE

Technical strategy & system design

Owns the architecture roadmap, technology choices and platform evolution — accountable for scalability, security and technical debt management.

02 / ENGINEERING TEAM

Team structure & delivery

Scales the engineering organisation, defines team topology, owns hiring standards and delivery processes. Builds a team that ships.

03 / PRODUCT PARTNERSHIP

Product-engineering alignment

Partners with product leadership to balance technical excellence with shipping velocity. Translates business needs into technical reality.

04 / TECHNICAL CREDIBILITY

Board, investor & customer trust

The technical voice in the boardroom, during due diligence, and with enterprise customers. Brings instant credibility to technical discussions.

component · comparison table
03 / alternative models

Fractional CTO vs alternatives.

How the fractional model compares to interim, executive chair, advisor and full-time appointments.

Fractional CTO
Tech consultant
Time on site
1–3 days/week, embedded
5 days/week, temporary
Engagement
Ongoing portfolio member
Gap-filler until permanent
Duration
12–24 months, renewable
3–9 months, finite
Cost
Day rate, time used
Day rate, full-time density
Multi-client
Yes — portfolio operator
No — exclusive for term
Fractional = embedded + part-time. Consultant = project + detached.
component · calculator
04 / economics

Part-time CTO cost.

Model the cost vs a full-time CTO, or what you could earn across your portfolio.

Day rate £1,400
Days per week needed2
Weeks engaged / year46
Your £1,400/day sits at the 58th percentile for UK fractional CTOs 800–£2,000 band).
Your cost
Total year-1 cost
£144,256
Total year-1 cost · 2 days/week · incl. our 12% fee
Fractional CTO cost
£144,256
Full-time CTO cost
£268,800
You save £124,544 (46%)
Indicative. Full-time loaded = base + 25% recruitment + 15% employer NI + 20% benefits/equity.
component · IR35 compact
05 / structure

Outside IR35 by default.

All fractional CTO engagements are structured outside IR35 from day one. Here's how — reference: HMRC off-payroll working (IR35) guidance and the CEST tool.

01 / CONTROL

You control the "how"

Fractional CTOs set their own working methods, hours and location. The company defines the outcome; the CTO decides how to achieve it.

PASS
02 / SUBSTITUTION

Right of substitution

Contract includes an explicit right to provide a suitably qualified substitute. This is rarely exercised but legally present.

PASS
03 / MUTUALITY

No obligation

No mutuality of obligation — the company isn't obliged to offer work beyond the agreed scope; the CTO can decline additional work.

PASS
component · decision cards
06 / timing

When to hire a fractional CTO.

Four situations where a fractional chief technology officer is often the right answer — typically engineering teams of 5–25 that need CTO-level strategy, architecture oversight and team leadership without a £120k–£200k+ full-time cost.

SCENARIO 01

Technical founder scaling

The technical founder wants to focus on product vision or step into CEO role. A fractional CTO handles architecture, team scaling and engineering processes while the founder transitions.

Bridge technical leadership while founder evolves role
SCENARIO 02

Platform rebuild

Legacy tech debt blocking growth. Need senior technical leadership to architect and execute a migration while keeping the lights on. Too critical for consultants, not permanent enough for full-time.

CTO expertise for transformation without long-term cost
SCENARIO 03

Team scale 10→50

Engineering team outgrowing founder/VP leadership. Need CTO-level thinking for architecture, org design and technical strategy but not ready for £200K+ package.

Strategic tech leadership at the right stage cost
SCENARIO 04

Due diligence prep

Fundraising or acquisition on horizon. Need credible CTO presence for technical due diligence, architecture documentation and engineering maturity. Fractional CTO brings instant credibility.

Board-ready technical leadership for critical moments
component · hiring guide
07 / the buyer's guide

How to hire a fractional CTO.

The buyer's guide, compressed: scope, source, assess, then a structured trial. A vetted CTO for hire typically starts within 2–4 weeks — against 3–6 months for a permanent search.

PLAYBOOK 01

How to hire a fractional CTO for a startup

At pre-seed and seed, published tiers run roughly £1,795–£3,500 a month at about one day a week, rising to £4,000–£7,000 through seed to Series A at one to two days. Scope the engagement to a specific outcome — a technical assessment, an architecture decision — rather than an open-ended strategic retainer. It is easier to judge and cheaper to stop.

Start with a scoped project; convert to a retainer once it works
PLAYBOOK 02

How to hire a fractional CTO team

Sometimes one part-time person cannot carry it. The common shape: a fractional CTO at 1–2 days a week owning architecture, standards and the board relationship; a delivery or engineering manager at 3–5 days running the day-to-day; and flexible contract build capacity underneath both. Insist on one accountable technical owner in writing — and an exit plan that documents the team out of a job.

One accountable owner · an exit that isn't a cliff
PLAYBOOK 03

The four-step process

Define your technical scope and budget — monthly retainers typically £2,000–£8,000 at 1–2 days a week. Source through investor and advisor referrals, specialist platforms and technical networks, or submit a brief to us. Assess with a portfolio deep-dive and technical scenarios against your stack. Then start with a structured 1–3 month trial with clear deliverables.

Most successful engagements start with a scoped project, not a retainer
component · workflow
08 / vetting

How we vet fractional CTOs.

Every candidate through the same four-stage verification before they reach your shortlist.

01

Pedigree screen

Verify prior CTO/VP Eng tenure, tech stack and scale. No consultants-pretending-to-be-fractional.

SOURCING
02

Technical fit

Match to your stack, architecture needs and engineering culture — not just buzzwords.

MATCHING
03

Reference deep-dive

Speak to recent fractional clients and engineering teams. Real delivery, not just strategy.

VERIFY
04

Shortlist + analysis

3–5 candidates, each with rate percentile, technical fit and IR35 structure attached.

48 HOURS
component · FAQ
09 / questions

Fractional CTO FAQ.

Common questions from companies on the buy side and CTOs looking for fractional work.

What is a fractional CTO?
A part-time chief technology officer who owns your tech strategy within a defined scope — leading architecture, the engineering team and technical decisions. Not a consultant, not an advisor: the CTO, 1–3 days a week.
How much does it cost to hire a fractional CTO?
UK median is around £1,400/day, typically 2 days a week; monthly retainers run £2,000–£8,000 for 1–2 days a week. A 2-day mandate runs ~£170K all-in for the year — versus ~£320K loaded for a full-time CTO. Use the calculator above for your numbers.
How do I hire a fractional CTO?
Submit your brief and we'll shortlist 3–5 vetted fractional CTOs within 48 hours, each matched to your tech stack, stage and culture.
Are fractional CTOs outside IR35?
Yes — outside IR35 by default. Our contract template carries right of substitution, no mutuality of obligation, and contractor-controlled working; tested against HMRC's CEST tool.
When should we hire a permanent Chief Technology Officer instead?
When you need deep, daily technical leadership for sustained product development and your engineering team exceeds 20+ people. A fractional CTO often helps you scale to that point.

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