Custom internal systems
We design and build the system around your processes: sales, billing, inventory, manufacturing, logistics, administration and the specific modules your operation needs.
Software studio · Argentina (UTC-3)
Custom software for businesses that have outgrown their systems.
We design and build internal systems, back-office platforms and bespoke SaaS around how your business actually works — not the other way around. We won't show you a demo: we'll show you a real, complex system running in production.
- business modules & processes
- 100+
- isolated data per company
- Multi-tenant
- ERP in production
- Since 2024
We work with companies that manufacture, sell and distribute, with clinics that manage appointments and patients — and with businesses that need to invoice in Argentina without errors.
The problem
Off-the-shelf software makes your business fit the tool
Generic software is designed for an average company. Yours isn't one.
It has its own way of quoting, collecting, manufacturing, purchasing and delivering. When the software ignores those processes, you end up bending your operation to fit the tool — or keeping spreadsheets, manual steps and parallel controls alive.
A custom system inverts the equation: the software adapts to your operation. Processes get centralized, data stays consistent, and the information is there when you actually need it.
Services
What we do
Four ways of working with us, all under the same principle: software that ends up running, documented, and under your control.
Modernizing existing systems
That old system everything depends on but nobody dares to touch. We map it, document it and modernize it in stages, without stopping the operation.
Integrations
We connect the systems you already use: invoicing (including Argentina's ARCA), payment providers, e-commerce, APIs and the spreadsheets that still require manual entry. We run our own invoicing platform in production.
Evolution & support
Development doesn't end at deploy. We stay with the operation: resolving incidents, monitoring the system and evolving the modules the business needs next.
Real-world case
A real system, not a list of technologies
The system that introduces us best is YSY Empresa: a multi-tenant ERP built end-to-end for Ripser — a manufacturer of commercial fixtures and refrigeration units — in production since 2024.
Sales and quotes, customers, receivables, cash, manufacturing with traceability, multi-warehouse logistics and payroll: the whole operation on a single platform.
Over a hundred business modules, multiple companies and warehouses, audited money flows and automated tests on critical processes.
Also built by us
Our own products, in production
Besides bespoke systems, we build and run our own products. Same way of working, applied to concrete problems.
Sistemas MDQ
Argentine e-invoicing (ARCA)
An electronic invoicing platform for Argentine businesses, integrated with ARCA — the national tax authority. It issues type A, B and C invoices with CAE authorization in seconds, with stock, price lists and the digital VAT ledger built in.
- Validates everything before requesting the invoice number: no burned sequence numbers.
- Recovers invoices issued outside the system.
- Exports the digital VAT ledger (RG 4597), reconciled and accountant-ready.
- Scheduled invoices by email, plus a REST API to invoice from your own ERP.
- ARCA WSFEv1
- REST API
- Digital VAT ledger
YSY Agenda
Online appointments for healthcare centers
Let patients book on their own so reception can attend instead of coordinating by phone. An appointment platform built end-to-end, in use at a multi-specialty medical clinic: each practitioner runs their own schedule and the clinic manages everything from a single panel.
- Online booking against each practitioner's real open slots: no double bookings or impossible appointments.
- Each practitioner manages their daily time slots, appointment length and blocked time.
- Appointments by specialty, with email confirmation to the patient.
- Clinic panel: patients (search by name or ID), practitioners, appointments filterable by status and period, and reports.
- React
- Spring Boot
- Docker
Testimonials
What the people who use it every day say
We went from spreadsheets and parallel controls to running the whole operation — sales, factory, deliveries and payroll — through a single system. And when we need something new, it gets built around how we work, not the other way around.
Sergio RipollCEO of Ripser · uses YSY EmpresaAppointments used to mean phone calls, back-and-forth and empty slots. Now my patients book on their own against my real schedule, and I manage it from wherever I am. Double-bookings are a thing of the past.
Dr. Antonella BottaroPediatrician · uses YSY AgendaWe ran the schedule in Excel and it worked, but it depended on me being there: every booking went through me, and coordinating several practitioners with different hours was a job in itself. Now clients book online against real availability, each practitioner manages their own schedule, and I have everything in one place. We gained order and time — and clients notice.
Matías AlonsoAdministrator at Club Spa - Petit Hotel · uses YSY AgendaI load my availability once and the system does the rest: patients only see the slots I actually have open. Less time coordinating, more time seeing patients.
Sacha CoronelPsychologist · uses YSY AgendaMethod
How we work — and where the trust comes from
Hiring a small studio has one advantage — you talk directly to whoever builds — and one fair question: what if they're gone tomorrow? The answer isn't a promise. It's how we work:
- You own the code.
- Everything we build for your company lives in repositories you own. No black boxes, no artificial vendor lock-in. The system, its documentation and the knowledge needed to maintain it stay under your control.
- Short, reversible releases.
- The system grows in stages. Each release reaches production in a controlled way and can be rolled back if something doesn't work as expected.
- Documented from day one.
- Process maps, technical decisions and operating manuals are written down. The project's continuity doesn't depend on one person.
- A direct line.
- From discovery to support, you talk directly to the person who designs and builds the system. No commercial layers, no middlemen, no tickets bouncing between teams.
The process, in 4 steps
- DiscoveryWe map your real operation: who does what, with which tool, and where it gets stuck.
- Solution designWe define scope, priorities and a first useful release. We don't quote "the whole system" before understanding how your operation works.
- Staged developmentEach stage ships to production and gets used; what we learn feeds the next one.
- Operation and evolutionSupport, monitoring and continuous improvement.
Stack
What we build with
We choose mature, boring-in-the-best-sense tools: proven, maintainable technology with professionals available in the market.
- Java 25
- Spring Boot
- Node.js
- React
- TypeScript
- MariaDB / MySQL
- Flyway
- Docker
- Nginx
- GitHub Actions
FAQ
What everyone asks before writing
The short, honest answers. For everything else there is the first conversation, which is free.
How much does a custom system cost?
There is no price list because no two operations are alike: cost depends on scope. What is fixed is the method: we map your operation, define a first useful stage and quote it as a fixed price before writing a line of code. You know what each stage costs before approving it — and the fair comparison isn't against spending nothing, it's against years of licenses for software that never quite fits, plus the hours your team loses to spreadsheets and parallel controls.
What if I only need invoicing, not a custom system?
That's what Sistemas MDQ is for: our electronic invoicing platform integrated with Argentina's tax authority (ARCA). Invoices, credit and debit notes, MiPyME credit invoices and the digital VAT ledger, at a flat monthly price with no per-invoice fee and no lock-in. If you already run your own system, its API issues the invoice from inside.
How long until we can actually use it?
We don't deliver "the whole system" at the end: the first useful stage reaches production in weeks, not years, and from then on the system is in daily use while it keeps growing. Each following stage builds on what the real operation teaches.
What happens to our current data, spreadsheets or legacy system?
It gets migrated. Part of the initial mapping is understanding where your data lives today — spreadsheets, a previous system, paper — and planning the import and cleanup. If needed, the new system runs alongside the old one until cut-over, without stopping the operation.
How do you bill?
Per stage: each one is quoted and approved before development starts, and invoiced against software delivered and working. After launch, evolution and support are agreed as a monthly service sized to the pace the business needs.
What if you disappear tomorrow?
The code, the documentation and the repositories are your property from day one. Any competent team can pick the project up and continue it: no black boxes, no lock-in licenses, no artificial dependency on the vendor.
Do you work with companies outside Argentina?
Yes — we work remotely, in UTC-3, with working hours that overlap both US and European time zones. Initial mapping is done over video calls, in English or Spanish.
Contact
Let's talk about your operation
Tell us what problem you have — even if you don't yet know whether the answer is a new system, fixing the current one, or connecting what already exists. We work remotely from Argentina (UTC-3), with working hours that overlap both US and European time zones. The first conversation is free and without obligation.
ysysoftwareadmin@gmail.com
You talk directly to Mariano Van Staden, founder of YSY Software. He leads the team that designs and builds every system — and still writes code himself: no salespeople, no middlemen between you and your project.
Team
Work with us
We don't always have open positions, but we're always interested in meeting developers who enjoy building real business systems: the kind that touch money, stock and data that cannot be lost. If you like how we work, we'd like to meet you.