An independent house for the software we build and keep.
Three products, one operator. Every one of them starts inside the business it serves: we run the operation first and build the software second.
Mandate
Small, paid for by revenue, built to still be here.
Khrestenkov & Co holds and operates a short portfolio of software businesses. We have taken no outside capital, we are not for sale, and we are not in a hurry. Every product is expected to pay for itself and to still be standing in ten years.
The thesis is narrow and it is not about technology. Conservative industries — the ones that have run the same way for thirty years and are good at what they do — are being asked to keep pace with a market that moves faster than the systems they were built on. They do not need disrupting. They need the parts that leak quietly to stop leaking: payments that fail, agreements that lapse, work nobody scheduled. Nothing breaks loudly; it simply stops renewing. We build the software that catches it, and we build it from inside the operation rather than from a deck.
What we cannot buy, we build. What we build and cannot sell, we open. The house is structured so that none of those three outcomes counts as a failure, and so that whatever does not work still leaves something behind — in one place, under one name, rather than scattered across dead links.
A machine can do the work. It cannot be liable for it.
Building has become genuinely easy, and that is a good thing: more people can make more things than at any point before. What has not become easier is everything that comes after. Standing behind the thing. Answering for it at two in the morning. Keeping it running in year three, when the API has changed and whoever built it has moved on. That is the argument for a house with one name on the door — and here it is not a policy but a legal fact: a sole proprietorship carries unlimited personal liability, so the name on the door is the name on the hook.
Alignment
Deciding what the thing is for, and what it must not do, before any of it exists. The cheapest hour in a project and the first one skipped.
Accountability
What happens when the alignment turns out to have been incomplete, which it always does. The fault gets found, the fix gets shipped, and the cost lands on whoever set the goal.
Alignment without accountability is a promise. Accountability without alignment is an apology. Responsibility is neither on its own — it is holding both ends, and knowing which one the moment is asking for. It is also why things get finished here: the distance between noticing a problem and shipping the fix is one person wide, and that person cannot delegate the consequence.
Products
Three products, one ledger.
Each product carries its own name, its own customers and its own P&L. The house carries the standards.
Record
Numbers first. Names when the contracts allow it.
We do not publish client names or wordmarks without written consent. Everything below is work carried out directly.
- 1,100+
- HVAC membership accounts under direct management
- 880+
- Accounts live on MemberBay at first deployment
- 25
- Days from empty repository to production on the first build
- 1
- Signature required to change direction — no board, no committee, no outside capital
The office
One principal. No committee.
Daniil Khrestenkov
Founder & Principal · Montevideo, Uruguay
Ran the membership business at a US home-service contractor — over 1,100 maintenance agreements, and the renewals, billing and collections behind them — before writing a line of MemberBay. The product exists because the reporting stopped scaling.
Twelve years before and alongside that, across industries with little in common: industrial manufacturing sourced overseas, high-ticket retail sold in Mandarin, cross-border e-commerce over 45,000 SKUs, event ticketing at volume, an early-stage IoT venture. Three continents, four languages, a Wharton fintech certification. Builds in Python and TypeScript.
The through-line is narrower than the list looks. In every one of them the job was the same — stand between two parties who do not speak each other's language, a factory and its buyer, an engineer and a customer, a technician and a billing system, and make the exchange hold. The software does the same thing. It is why an unfamiliar industry is not a risk here: nothing gets built before the operation is understood.