A fractional CTO is a senior technical leader working part-time across one or several companies. In the UK they cost roughly £800 to £1,500 a day, or £3,000 to £8,000 a month on a retainer of one to two days a week.
That range is wide because the title is doing a lot of work. It covers a board-level adviser who attends one meeting a month and a hands-on engineer writing code two days a week, and the gap between those two jobs is enormous.
What they all have in common is this: you are buying judgement, not output. Whether that is the right purchase depends entirely on which of those two you are short of.
The three cases where it is genuinely the answer
You are about to spend serious money and cannot assess the proposal
You are non-technical, you have a quote for £80,000, and you have no way of telling whether it is reasonable, whether the approach is sound, or whether the agency is any good.
Three days of independent review before you sign is the single highest-return technical spend available to an early-stage founder. It costs a few thousand pounds and it routinely saves a multiple of that, either by catching a bad proposal or by giving you the confidence to proceed with a good one.
You have engineers but no one to lead them
Two or three developers, all capable, none responsible for the shape of the whole thing. Decisions get made by whoever touched the file last, and nobody owns the consequences six months out.
This is a real job and a part-time senior can genuinely do it, especially if the alternative is a full-time hire you cannot yet justify.
Something external is about to look closely
Due diligence on a raise or an acquisition. An enterprise customer's security review. A regulator, an ISO audit, a penetration test with a report somebody will read.
These need someone who has been through one, can tell you what will be asked, and can get the answers into a defensible state. That is a short, well-defined engagement, and it is worth paying properly for.
Why it is sold more often than it is needed
Because advice is easier to sell than work, and because "you need a CTO" sounds more serious than "you need somebody to build this".
Here is the pattern we see most often. A founder knows exactly what the product needs to do. They have a list. The list is not wrong. It is simply not getting built, because there is nobody to build it.
They are told they need technical leadership. They buy two days a month of senior advice, and what they get back is a well-reasoned architecture document and a hiring plan.
The list still is not built. It is now documented, which feels like progress and is not.
If you can already articulate what you need and the problem is that nothing ships, you do not have a leadership gap. You have a capacity gap, and the two have completely different cures.
The cheaper thing most founders need
Shipping capacity with the judgement built into it.
The reason fractional leadership gets sold separately is that in most arrangements the people deciding and the people building are different people, in different companies, with different incentives. So the deciding has to be bought on its own.
It does not have to work that way. When the people making the architecture decisions are the same people writing the code, the decisions are made in the only place they can be made well: with full knowledge of the codebase, and with the person making them living with the consequences.
That is how our product team subscription works. £4,500 a month for a senior designer and a senior developer working your queue one request at a time, and the architecture judgement is part of the work rather than a line item on top. Build versus buy, what to host where, which third party to wire in, when to stop adding and start consolidating — those get decided by the people doing it, because they are the ones who will be living in it in March.
Some of it genuinely is a separate engagement: sitting on your board, representing the technical function to investors, running a hiring process end to end, or owning a compliance programme. Kryspin takes that work, as a fractional CTO, separately from the subscription. He is our co-founder and technical lead, he has built and run the architecture behind every product on this site, and he does the due diligence, the proposal reviews and the pre-raise technical readiness himself.
The difference worth knowing is that he is a working engineer, not an adviser who stopped writing code a decade ago. The architecture calls come from someone who will also live in the codebase, which is the whole argument of this post.
How to tell which you need
One question, asked honestly.
Can you write down what needs building in the next three months?
If yes, and it is not getting built, you need capacity. Buying advice will produce a better-organised version of a list that still is not built.
If no — if you genuinely do not know whether to rebuild or extend, whether to go multi-tenant, whether that integration is a weekend or a quarter — then you need judgement first, and it is worth paying for on its own.
If the answer is somewhere in between, which it usually is, you want the version where both come from the same people.
What we would suggest
If you are unsure which of these you are, book thirty minutes. We will tell you honestly, including when the answer is a fractional CTO rather than a team, or a hire rather than either. Kryspin does that work too, so the recommendation costs us nothing either way.
If you already know what needs building and want it built, the plan is here and starts this week. A few places open each month at £3,500 a month for the first six months.
And if what you actually need is one bounded thing looked at properly — a proposal reviewed, an architecture questioned, a codebase assessed before you commit — our two-week kickoff sprint is £1,950 and ends in a written report you keep either way.
