The round closed, the CTO search will take months, and something has to happen in the meantime. Four options present themselves, usually in the form of four very different invoices. Comparing them on price is the obvious move and the wrong one, because they are not substitutes — each solves a different problem.
The four options on one page
| What you get | Typical cost | Fails when | |
|---|---|---|---|
| Fractional CTO | A day or two a week of senior judgement: decisions, hiring, architecture calls | $4k–12k / month, ongoing | You needed hands. They are not going to build it |
| Agency / studio | A team that ships features to a brief | $15k–40k / month | Nobody internal understands what was built |
| Senior engineer hire | One person, full time, permanent, invested | $120k–180k / year plus equity and 2–4 months to find | You needed a decision this month, not in four |
| Fixed-scope audit / sprint | A written map: what exists, what is at risk, what to do in what order | $7k–35k, once, bounded | You needed someone to execute the plan afterwards |
Before comparing those numbers, answer a different question: which of the two shortages do you actually have?
Judgement or hands?
Almost every founder in this position is short of one of two things, and they are rarely short of both in the same proportion.
- Short of judgement. You have people who can build, but nobody who can decide what to build, in what order, and whether the answers you are being given are good ones. A fractional CTO or an audit addresses this. More developers make it worse.
- Short of hands. You know exactly what needs doing, the plan is sound, there is simply nobody to do it. An agency or a senior hire addresses this. A fractional CTO will hand you a better plan for work that still is not happening.
Getting this backwards is the most common expensive error here. Hiring an agency when the shortage is judgement produces a lot of shipped work in the wrong direction — quickly, professionally, and on budget.
The question that separates the four
Ask each candidate or firm the same thing: what do I own on the day this ends?
- Fractional CTO — better decisions, a hiring plan, and usually a stronger team. Little written down unless you ask for it explicitly. Ask for it explicitly.
- Agency — working software, and a knowledge gap exactly the size of the engagement. This is the failure mode: the product works and nobody in your company can change it.
- Senior hire — everything, as long as they stay. Which makes this the option with the sharpest key-person risk, the thing investors ask about in technical due diligence.
- Fixed-scope audit — a document. Its entire value is that it survives whoever wrote it, and it is the only one of the four that makes your eventual CTO hire faster rather than slower.
The real question is never what it costs per month. It is what remains in the building after the invoices stop.
Where each one is genuinely the right call
- Fractional CTO — you have two or three developers and no one senior. You need someone to set direction, sit in on hiring, and be accountable for technical decisions while you search. Insist on written decisions, or you are renting judgement that leaves with them.
- Agency — the scope is genuinely separate and well defined: a mobile app, an integration, a migration. Something with a clear boundary that your team does not need to own afterwards.
- Senior hire — you know what to build and will keep building it for years. Start now, because the search is long, and accept that it does not solve this quarter.
- Fixed-scope audit — you do not actually know where you stand. Nobody can honestly answer how long a new engineer needs before shipping, or what breaks under load, or what is at risk. Buying a map first makes all three other options cheaper.
Combinations that work
These are not exclusive, and the sequences below come up repeatedly because they work.
- Audit, then hire. The written assessment becomes the brief for the CTO search and the first thing you hand the person who takes the job. It also makes your job description specific, which visibly improves candidate quality.
- Audit, then agency. A clear map turns a vague agency brief into a scoped one. This is usually the difference between an agency engagement that works and one that does not.
- Fractional CTO, then permanent. Some fractional CTOs will run the search for their own replacement. The good ones offer it before you ask.
How to decide this week
- Write one sentence describing what you cannot do right now. "We cannot ship" and "we cannot tell whether what we are shipping is sound" point at opposite options.
- Ask each candidate what you own when it ends, and compare the answers rather than the rates.
- Check the reversibility. An audit ends. A monthly retainer has to be actively stopped, and rarely is.
- If you cannot answer the four questions in Seven Questions to Ask Your Developers, buy the map first. Everything else is a guess priced like a decision.
