Fractional CTO

When you need a fractional CTO — and when you do not

I sell this service, so treat the first list with the scepticism it deserves and the second list as the part that costs me money to write.

Six signals you need one

1. Technical decisions are being made by people whose job is not technical decisions

A founder picking a database on the basis of a conference talk. A commercial lead agreeing an integration deadline nobody costed. These decisions are cheap to make and expensive to reverse, and reversal usually lands a year later on someone who was not in the room.

2. Estimates keep slipping and nobody can tell you why

The distinction that matters is whether your team can explain the slip. "The auth rewrite took longer because the old sessions could not be migrated in place" is a team doing its job. "It's just taking longer" repeated over three sprints is an absence of technical leadership, and no amount of extra developers fixes it.

3. You are about to make a technical hire with no technical interviewer

This one has a hard number attached. A mis-hire at UK engineering salaries costs the recruitment fee, a notice period, and a quarter of output — see the comparison page for the build-up. A few days of someone who can actually assess the candidate is cheap against that.

4. You inherited a system nobody on the current team built

An agency handover, a departed founding engineer, an acquisition. Somebody has to work out what is load-bearing before the first change breaks something at the far end. That is a finite piece of work and an unusually good fit for a short retainer.

5. Due diligence is coming

Technical due diligence asks questions your team has probably never been asked in that form: what happens if this person leaves, where is the data, what is the recovery position, who owns the code. Finding the gaps a month before is a different experience from finding them in the data room.

6. You are the technical person and you are now the bottleneck

Common in technical founders around the ten-person mark. You are still the only person who can approve anything, so everything queues behind you, so you cannot do the work that would remove the queue. What is needed here is not more of you.

Four signals you do not

1. The problem is capacity, not direction

If you know exactly what to build and there are simply not enough hands, hire hands. A fractional CTO will tell you what you already know and cost more than a contractor who would have shipped some of it. Development work is a different purchase from leadership, and conflating them is expensive.

2. You have one developer

There is no team to lead. What you have is a working relationship between you and one person, and adding a third party to it usually makes it worse. If that developer is good and you disagree with them, the answer is a conversation. If they are not good, the answer is a different developer.

3. What you actually need is a project manager

If the complaint is that nobody knows what is happening, when things will land, or who is doing what, that is delivery management. It is a genuinely different skill, it costs substantially less, and hiring a CTO to do it wastes both of you.

4. You have not decided what you are building

The hardest one to hear. If the product changes shape every few weeks, no technical leadership will help, because every decision gets invalidated before its consequences arrive. Settle the product question first. A technical person can help you scope it in a few days — that is a piece of work, not a retainer.

The cheaper thing to try first

Before any retainer: pay someone senior for two days to look at what you have and write you an honest assessment. Codebase, architecture, team, the three decisions that matter in the next six months.

Sometimes the answer is that you have a real problem and need ongoing help, and now you both know what shape it is. Often enough the answer is that things are fine and you were anxious, or that the fix is one hire or one decision. Either way you have spent a four-figure sum rather than committed to a five-figure year, and I would rather sell you the two days and be right than the retainer and be wrong.

If you want to work out the money side, what a fractional CTO costs in the UK has the sourced figures.