Information repeats itself
The same data lives in a spreadsheet, a message and a system — and no one knows which version is correct.
Product, process and engineering
Your process deserves a system built for it.
I turn disconnected spreadsheets and tools into custom software — from the first conversation to a product that keeps evolving.
Sound familiar?
The problem isn't a lack of effort.
It's too many patches.
When a process outgrows the system meant to support it, the team starts working for the tools instead of the other way around.
The process becomes invisible
The owner has to ask several people before understanding where a task actually stands.
Simple tasks turn manual
A small change requires copying, checking and notifying — always depending on someone's memory.
There's a system hiding here
Not necessarily bigger. Just more coherent with how the operation actually runs.
From chaos to product
Three stages.
One continuous evolution.
I don't start with code. First I locate the problem, scope the first version, and define how we'll know it works.
01
System Mapping
Understand before building.
Current flow, tools, bottlenecks and a clear scope for the first version.
02
Core System
Ship value into production.
A usable first version, built in milestones and validated against written criteria.
03
Evolution & Support
Keep the product aligned with the business.
A prioritised backlog, continuous improvements and reliability without hidden, unbounded work.
Selected work
Engineering you can actually see.
Every project has to show process, decisions and real outcomes — no staged screens, invented metrics or technology used as decoration.
See all projects
Live
Not published yetIgreja Batista Sião
Institutional landing page with a layered hero and a documented identity.
- Astro
- TypeScript
- GSAP
- Sharp
This project is built, but it has no public address. The preview runs from this site.
Who builds it
Direct access to the person
who thinks and builds.
I'm Mario Matheus, a software engineer and founder. My work is turning complex processes into systems that are clear, usable and built to evolve.
There are no commercial layers between you and the person deciding the architecture. The conversation, the decisions and the technical ownership stay close.
Scope before code Direct communication Delivery in milestones
FAQ
A few things worth knowing
before you reach out.
Short, direct answers about how the work actually happens — the rest is in the portfolio.
What kind of work does Mario take on?
Custom software for processes that outgrew the tools supporting them — replacing spreadsheets and disconnected tools with a system that matches how the operation actually runs, not a bigger one for its own sake.
Does he jump straight into code?
No. The first stage is System Mapping: understanding the current flow, the tools in use, the bottlenecks, and scoping a first version before any code is written.
What's a concrete example of something he's shipped end to end?
Nexo, a two-sided talent marketplace with AI-assisted evaluation. He is the founder and engineer in charge — product, architecture, database, authentication, billing and interface all went through his hands. It has been live in alpha since June 2026, and won Campus Mobile 2026.
What technical judgment calls has he made on a real product?
On Nexo: one deploy instead of microservices, because the bottleneck was finding the product, not scaling infrastructure; and tenant security and economy rules were prioritised before widening the product's surface.
Is the AI feature in Nexo just a marketing layer?
No, by design. The AI organises and standardises evidence of a candidate's work — it is not sold as an objective judge and does not replace the hiring decision.
Does the portfolio only show live products?
No. Every project shows its real state: what is live can be visited at its own address, and what has not been published yet can be seen running directly from this site, as a preview.
Who owns the decisions on a project — is there a layer between the client and the person building it?
No commercial layer. The conversation, the decisions and the technical ownership stay with the same person from start to finish.
How can someone get in touch?
Through the contact form, which prepares a WhatsApp message — nothing you type is stored on the page — or directly by email or WhatsApp. Separately, and worth saying: the site uses Google Analytics to measure audience, which involves a cookie. It counts visits in aggregate and never receives anything typed into the form.
Does pricing follow a fixed rate or a published range?
Neither. Pricing is set after System Mapping, because that stage is what reveals the actual size of the work: how much of the flow is in scope, how many integrations with existing tools are involved, and how much of the process needs rebuilding rather than just digitising.
How long does a project take?
It depends, and quoting a number that won't hold up helps no one — not even for System Mapping. What drives the variation is the size of the flow, the number of integrations, and how available the people who know the process are on the client's side. Delivery happens in milestones, so a usable first version of the Core System ships before the full system does.
Is this a one-person operation?
Yes, end to end: architecture, code, and every decision in between. No fixed team, no layer between the client and the person building it — the same person owns the work from the first conversation through to production.
First step
Let's find the system hiding inside your operation.
Tell me briefly where the process gets stuck. I put together the message and we continue over WhatsApp — no signup, nothing stored on this page.
Twenty minutes can be enough to know if there's a real opportunity here.