Should you hire a fractional CTO at all?
Crescentic offers CTO as a service for startups and boards that need a senior technical voice without a full-time executive hire: architecture and roadmap, build-versus-buy, AI strategy, hiring, security audits and technical due diligence. Often the honest answer is that you do not need one, and we will tell you that. When you do, the engineers who would build the recommendation are in the same team.
We have told a client they did not need the full-time DevOps hire they were considering, because at the size and stage they were it did not make sense. That is the same test we apply to this arrangement.
Most companies at this stage have a small number of choices a year that matter enormously: the architecture, the platform bet, the first engineering hire, whether to build the thing or buy it. In between there are a lot of weeks where an executive would be underused. That gap is what the arrangement is for, and it is our opinion rather than a rule.
Three versions of this we will turn down, because they go wrong reliably. We do not take equity in place of payment. We do not take a full-time scope at a fractional price, which is the most common way this arrangement sours. And we are not a way to defer hiring a permanent CTO you have already decided you need, though we are happy to be the interim while you run that search and to sit on the panel.
What does a fractional CTO take on?
Hire a fractional CTO when you do not need hands on keyboards. You need someone who has made this decision before, sitting at the table when it gets made, and still around when the consequence arrives.
- Architecture and technology decisions, with the reasoning written down.
- Build versus buy, evaluated on total cost rather than licence price.
- AI strategy: what to build, what to buy, and what to wait on this year.
- Hiring: the role, the interview, and the assessment you cannot make yourself.
- Vendor evaluation, including the technical claims in the contract.
- Board and investor conversations, as the technical voice in the room.
- Security audits, certification, and technical due diligence.
Advice is cheap to give and expensive to be wrong about.
Fractional, interim and advisory have blurred into each other, and a good advisor is worth having. The line we care about is narrower: whoever makes the call should still be there a year later when the consequence arrives. That is the only honest test of whether the advice was right.
What does this look like on a real engagement?
The clearest example is a compliance and global-mobility platform used to set up entities, move staff and stay legal across more than 170 countries. We build and maintain its web application and own the AWS infrastructure it runs on, so the leadership work sits on top of that rather than beside it.
That combination is the argument for this service line. The people answering the auditor’s questions are the people who moved that platform from hand-managed Docker Compose hosts to Terraform-defined AWS across four environments. There is no translation layer between the technical leadership and the technical work.
When do you need one, and when do you not?
| Advisor | Fractional CTO | Full-time CTO | |
|---|---|---|---|
| Owns the decision | Offers a view | Yes | Yes |
| Present for the consequence | Rarely | Yes | Yes |
| Cost | Low | A fraction of a salary | Salary plus equity |
| Right when | You need one conversation | Decisions are big but not daily | Technical leadership is the daily job |
| Can execute what they recommend | No | Yes, our engineers | Yes, their team |
We will tell you when the answer is a full-time hire. If technical leadership has become a daily job at your company, a fraction of a person is the wrong shape and stretching the arrangement to fit serves nobody. In that case the useful version of this engagement is helping you hire the person and handing over cleanly.
How the engagement runs
- 01
Start with what is actually in front of you
A funding round, an audit, a platform decision, a hire. Something concrete and dated. The engagement is shaped around it: a retainer, a bounded three to six months while you recruit, or something closer to joining the team.
- 02
Read the system before advising on it
The codebase, the infrastructure, the release process and the team. Advice given without this is worth what it costs to produce.
- 03
Be in the room where it is decided
Board conversations, investor calls, vendor negotiations, interview panels. The technical voice has to be present when the decision happens, not consulted afterwards.
- 04
Stay for the consequence
Decisions of this kind reveal themselves over quarters, and we are still there when they do. When something needs building, our own engineers build it rather than a procurement process. That is the part a solo fractional CTO cannot offer.
When it has not worked
One engagement started the way this arrangement usually does. The CTO seat at a US startup building a platform for people to record their stories and memories, taken personally, with Crescentic engineers brought in at the chief executive’s request as the build grew. The product got built and it still runs. The company could not sell it, and the engagement ended there.
We put that here because a page like this one is otherwise a list of things that went well, and you should be suspicious of that. A fractional CTO can get the architecture right and the hiring right and still be attached to a company that does not find its market. Technical leadership is not a substitute for commercial traction, and anyone selling it as one is selling you something.
Technical due diligence, from either side
If you are raising or being acquired, we prepare and defend the technical story, and fix what will not survive contact with a competent reviewer before the reviewer finds it.
If you are investing or acquiring, we assess the target: what is really under the hood, what the architecture diagram leaves out, which risks are real and which are cosmetic, and what the first year of owning it will actually cost. Written plainly, for people who have to make a decision with it.
01.When should we hire a fractional CTO instead of a full-time one?
When the technical decisions are consequential but not yet continuous. A pre-Series-A company usually has a handful of choices a year that will echo for a decade, and no need for an executive in every meeting in between. Also when you are hiring a permanent CTO and need someone credible in the room until they arrive, or when the board needs an independent technical read it can trust. If technical leadership has become a daily job, hire full-time. We will say so.
02.Can you do this for three to six months while we recruit a permanent CTO?
Yes, and it is one of the more useful versions of the arrangement. An interim CTO engagement with a defined end covers the decisions that cannot wait for your hire, and we can sit on the interview panel for the person replacing us. We would rather hand over cleanly than stretch an engagement past the point where it is the right shape.
03.What does a fractional CTO cost, and how do you price it?
We do not quote a retainer before reading the system. An estimate given before seeing the codebase, the infrastructure and the release process is a guess with a number attached, and it tends to be wrong in the direction that suits the person quoting. Expect a conversation, a read of what you have, and then a price against defined deliverables. The shape is flexible: a retainer, a bounded engagement, or something closer to joining the team.
04.What does a fractional CTO actually do day to day?
Architecture and technology decisions and the reasoning behind them. Build-versus-buy calls. Evaluating vendors and reviewing their contracts for the technical claims. Hiring: writing the role, sitting on interviews, assessing candidates you cannot assess yourself. AI strategy, meaning what to build, what to buy, and what to leave alone this year. Sitting in board and investor conversations as the technical voice. Supporting audits and diligence when they arrive.
05.Can you support an ISO 27001 audit or a security review?
Yes, and we do this on an ongoing basis. We support one client's annual ISO 27001 audit: the recurring evidence, the infrastructure questions, and the answers that need to hold up in enterprise procurement and security review. We are working with the same client on SOC 2 now. That work is easier when the same people also run the infrastructure being audited, which is generally our situation.
06.Do you do technical due diligence for investors or acquirers?
Both sides of it. We have supported a client through the technical diligence that accompanied their fundraising, as the technical voice answering an investor's engineers. We also assess targets for people considering an investment or acquisition: what is really under the hood, what the stated architecture leaves out, and which risks are genuine versus cosmetic.
07.How is this different from a consultancy strategy engagement?
A strategy engagement ends in a document. This one ends in something built, or in a decision you can defend to a board. The difference that matters is that we can hand work to our own engineers when a recommendation needs building, rather than passing you to a procurement process. Most fractional CTOs are one person. The recommendation and the delivery are the same team here.
08.What is a fractional CTO?
A senior technical leader who works with you part-time and carries real responsibility for technical decisions: architecture, hiring, vendors, roadmap, risk, without being a full-time executive hire. Also sold as CTO as a service, interim CTO or part-time CTO, and the labels have blurred. What separates the useful version from the rest is whether the person owns the decision and is still around when the consequence of it arrives.
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