A fractional technology leader is a sensible arrangement for a company that needs senior technical judgement and cannot yet justify a full time hire. It works well for decisions and oversight and badly as a substitute for the day to day leadership a team needs, and knowing which you are short of is the whole question.
What the arrangement does well
Technology choices that are expensive to reverse, hiring the first engineers and assessing candidates you cannot evaluate, reviewing a vendor's work and telling you whether it is sound, setting up practices that prevent predictable problems, and translating between the business and whoever is building. For a non technical founder buying development work, having someone on your side who can read a proposal properly often pays for itself in the first engagement.
What it cannot do
Day to day leadership. A team needs someone available when a decision is needed, who knows the codebase, who notices when someone is stuck and who is accountable for delivery. A few days a month cannot be that, and expecting it produces a team that feels unled and a leader who feels blamed for outcomes they could not influence. Once you have engineers who need direction daily, the arrangement has reached its limit.
Scope it around decisions and oversight
Define what the person is accountable for and what they are not, in writing. Good scopes are specific: attend these decisions, review vendor work monthly, own the hiring process for the first two engineers, and produce a technology plan by a named date. Vague scopes produce a monthly meeting with no visible effect and are the usual reason these arrangements end unsatisfactorily on both sides.
Plan the exit from the start
The arrangement should have an intended end: a full time hire, or the point at which the team no longer needs it. Agree what has to be true for that transition and make the fractional leader responsible for getting you there, including documenting decisions and their reasoning so a successor is not starting blind. An engagement with no exit condition tends to persist past the point where it is adding anything.
Questions people ask about cto as a service
What can a fractional CTO actually do?
Expensive-to-reverse technology decisions, hiring and assessing engineers you cannot evaluate, reviewing vendor work, setting up practices that prevent predictable problems, and reading proposals properly on your behalf.
What can it not do?
Day to day leadership. A team needs someone available when decisions are needed who knows the codebase and is accountable for delivery. A few days a month cannot be that, and expecting it leaves the team unled.
How should it be scoped?
Around specific accountabilities with dates: attend these decisions, review vendor work monthly, own hiring for the first two engineers, produce a technology plan by a named date. And agree what ends the arrangement.