Fractional CTO, full-time CTO or an agency: what does a startup need?

Founders without a technical co-founder, and teams whose CTO has just left, usually frame this as a hiring question. It is a question about the work. A CTO does two jobs: making the technical decisions, and leading the people who carry them out. A startup often has the first long before the second, and the three options differ mainly in which they cover.

Three options, three jobs

A fractional CTO does the part of the role that is judgement rather than headcount: choosing the architecture, cutting the roadmap with the founders, hiring the first engineers, checking what vendors propose and deliver, reading the code, and sitting on the calls where a technical decision gets made. The hours are agreed each month.

A full-time CTO does all of that and also leads the technical team every day: the standups, the delivery, the hiring, the incidents at night, with a stake in the outcome.

An agency builds the product. The advice it gives along the way comes with the build and is paid for by it.

Which one fits your stage

Before product-market fit. The product will change, and most of the important decisions are about what not to build yet. A full-time CTO with real equity is a large bet on one person before you know what the company is. In our judgement, this is where a fractional CTO earns the most: the decisions are expensive to get wrong, and the workload is small.

Between two CTOs. Someone has to know what is in the codebase, keep the team pointed somewhere, and help hire the replacement. A fractional CTO is a bridge with an end: the job is done when the new CTO starts from the decisions written down, not only from the code.

While a vendor builds. You need someone on your side who can check the estimates, read the pull requests and tell you plainly whether the work is sound. That person should not work for the vendor.

Scaling. When there is a growing team to lead, a hiring plan running and delivery to answer for every week, the role is a full-time job. Hire for it. A fractional CTO who says otherwise is protecting a retainer.

When the plan is settled, at any stage, and the open question is who builds it by a date, an agency is the right shape. The test is whether the plan really is settled, or only feels settled because nobody has challenged it.

What each costs, in shape

A fractional CTO is a monthly retainer, set by the hours the work needs. No salary, no equity, no long search first, and it grows or shrinks with the work.

A full-time CTO is a salary and equity, and the search. Finding someone senior enough to trust with all of your technology takes time, and a wrong hire at that level is slow and costly to undo. Worth paying once the job is full time.

An agency is a project price. You pay for build hours, and the advice is bundled in.

The conflict of interest

When an agency advises on what to build and then builds it, its advice and its revenue point the same way. That is an incentive, not dishonesty, and good agencies resist it. But the structure pulls towards building more, and a founder who cannot read code cannot tell a sound recommendation from a profitable one.

Bushido does both kinds of work, so this applies to us too. Our stance is that the advice stays apart from the build. A fractional CTO engagement is paid for judgement, not build hours, so the answer can be to build less, or nothing. If we review a vendor for you, we are not quietly bidding for the work. If you later want us to build, that is a separate engagement.

A simple test for anyone advising you: ask what they earn if you take their advice.

The three side by side

	Fractional CTO	Full-time CTO	Agency
When it fits	The decisions need a CTO, the workload does not	Leading the team is a full-time job	The plan is settled; you need it built
What it costs	A monthly retainer	Salary, equity and the search	A project price, advice bundled
Whose interest it serves	Yours; it can say build less	Yours, as part of the company	Yours and the agency’s; it sells the build
How much time it has	Agreed hours, and a call when it cannot wait	All of it	What the contract buys, on that project

How to tell which you need

Look at the technical questions on your desk this month.

Which architecture, should we build this at all, is this estimate fair, can you interview this engineer, what is actually in our codebase: you need judgement, and a fractional CTO fits.

Who runs the team tomorrow morning, who answers when production goes down, who manages the engineers we are hiring: you need a full-time CTO.

We know what to build; who can ship it by the date: you need a build team, ideally with someone independent checking its work.

What is this company’s code worth, before an investment or an acquisition: that is technical due diligence, a fixed piece of work, not a role.

Many startups need two of these at once. A fractional CTO overseeing an agency’s build is a sensible pairing, because it puts the advice and the build in different hands.

How we start

With one 90-minute session on the question that matters most, and a written follow-up with what to do next, in order. If the session answers it, you need nothing else from us. If not, a monthly retainer follows, and when the job fills a week, we help you hire the full-time CTO and hand over every decision written down.