Software, from the inside out.
I build complete web applications, integrations and automation for companies that need to simplify processes, connect systems and get digital products off the ground.
§01Services
Four kinds of work I have real experience in. Each one points to projects where I did something similar.
For companies that need to replace spreadsheets, organize operations or centralize information.
For companies whose tools don't talk to each other, or who repeat tasks by hand.
For founders and teams who need to turn an idea into a first usable version.
For teams that need to understand a problem or improve a system already in use.
§02Selected projects
Work done as an employee at companies, not as freelance contracts. Client names and internal details are left out; the descriptions stay at the engineering level.
Manufacturing · 2025 — 2026Professional experience
A warehouse management system built from scratch, kept in sync with the ERP and turned into a PWA for Android handhelds.
The warehouse needed to control stock, receiving, internal moves and shipping of materials, in step with the production orders and movements recorded in the ERP.
I built the WMS end to end as the company's full stack developer: the screens and stock rules, the ERP integration and the PWA version for the handhelds.
Receiving, internal moves, stock and shipping run on the company's own system, synced automatically with the ERP and usable on the warehouse's Android handhelds.
Details anonymized for confidentiality.
Healthtech · 2026 — presentProfessional experience
Every order from two products goes through a single microservice, which charges through third-party payment services and issues the service invoices.
Orders from the company's products are sent to a billing microservice, which integrates the third-party payment services and the service that issues Brazilian service invoices (NFS-e).
I contribute as part of the team: queue- and job-based processing, invoice storage on S3, reconciliation jobs and GraphQL in the back end of one of the products.
A single billing point for orders from two products, with asynchronous processing and routines that check transaction amounts and statuses.
Details anonymized for confidentiality.
Manufacturing · 2025 — 2026Professional experience
Centralized authentication, with permissions derived from corporate groups.
Authentication for the internal systems had to be centralized, and permissions had to follow the groups in the corporate directory.
I implemented the integration between the corporate LDAP directory and Keycloak, and permission management based on the directory's groups.
Centralized authentication for the internal systems, with access defined by the groups the company already maintained in its directory.
Details anonymized for confidentiality.
Industrial and commercial clients · 2024 — 2025Professional experience
Sales representatives managing several companies from a single workspace, with isolation between them enforced by permissions.
Sales representatives needed to manage purchasing for several companies in the same environment, with secure isolation between them.
I built the platform and implemented multi-tenant access control with CASL, and took part in gathering requirements with the clients.
A single workspace where sales representatives manage purchasing for several companies, with permissions that keep each company's data isolated.
Details anonymized for confidentiality.
Manufacturing · 2025 — 2026Professional experience
Migrating the company's internal system to an MVC architecture on an in-house framework inspired by Laravel.
The company's internal system was a legacy PHP application. The restructuring prioritized organization, maintainability, scalability and fewer external dependencies.
I led the restructuring into MVC, defined the architecture and coding standards, and built the Database Manager.
An organized MVC codebase with fewer external dependencies, and access to SQL Server and PostgreSQL through the same layer.
Details anonymized for confidentiality.
Manufacturing · 2025 — 2026Professional experience
ERP, CRM, OpenProject and Apache Superset connected to the internal system.
Data and processes were spread across the internal system, the ERP, the CRM and other corporate tools.
I built and maintained the integrations between systems, the platform integrated with OpenProject and the Superset dashboards.
Data and processes kept in sync between the internal system, the ERP and the CRM, with business indicators available in dashboards.
Details anonymized for confidentiality.
§03How it works
A simple process, adjusted to the size of each project.
I learn the context, the problem and the outcome you expect, before we talk about technology.
We agree on deliverables, priorities, assumptions and next steps, in writing.
I build in stages, share progress and adjust what's needed within the agreed scope.
I document what's needed, show how to use it, and we discuss next steps or maintenance where it makes sense.
§04About
I've been building software since 2023 — on a lending platform, on multi-tenant B2B systems and on the internal system of a manufacturing company, where I built a WMS that runs on Android handhelds, integrations with ERP and CRM, and the modernization of a legacy PHP codebase. Today I'm a back-end developer at My Smart Clinic, contributing to the billing microservice that connects payments and invoice issuing.
What drives me is understanding how things work underneath. I like architecture — clear responsibilities, explicit decisions, SOLID where it earns its place — and I like opening the black box even more: reading a framework's source, working out why an abstraction leaks, rewriting it from scratch to check that I really understood it. That's how Ion started.
Day to day, that turns into pragmatism. I aim for software the next person can maintain and integrations that fail predictably. I've gathered requirements directly with clients, led technical meetings and taken part in the architecture decisions of the systems I've worked on.
Since 2025 I've also taught programming logic, PHP and Python. Explaining a concept to someone who's just starting is the best test of whether I actually understand it.
§05Experience
Software engineering since 2023. Teaching since 2025, in parallel.
Travel in time
Drag along the line to see where I was and what I worked with, month by month.
That month
Stack at the time
Aug 2026 — present · Caxias do Sul, RS
The billing microservice that receives orders from My Smart Clinic and Olá Doutor and connects them to payments and invoice issuing.
Nov 2025 — Jul 2026 · Caxias do Sul, RS
Restructuring the internal system, a WMS wired to the ERP, and the integrations that connect the company.
Jan 2025 — present · Caxias do Sul, RS
Teaching programming logic, PHP and Python to classes of different levels.
Jan 2024 — Oct 2025 · Caxias do Sul, RS
Enterprise systems for industrial and commercial clients, from requirements to deployment.
Mar 2023 — Jan 2024 · Caxias do Sul, RS
A lending and investment platform, on web and mobile.
§06Expertise
Organized by system layer, not by logo. Hover a technology, or reach it with the keyboard, to see where it was used.
What's your problem?
Pick a situation to see what I'd use and where I've done something similar.
L1
APIs, business rules and the structure that keeps them maintainable.
L2
Web and mobile interfaces, from internal dashboards to PWAs.
L3
Where data lives and how code reaches production.
L4
Identity, permissions and how systems talk to each other.
Pick a technology
§07Side project · framework
Ion is a reactive micro-framework for server-rendered HTML — PHP, Laravel, any back end. State lives in Proxy-based stores; every binding is a small effect that records exactly the keys it reads and writes straight to the DOM, with no virtual DOM.
Write
Assigning state.count = 1 goes through the Proxy's set trap. If the value is the same, nothing happens.
Tracking
Bindings, effects and computeds recorded the keys they read on their last run. Only they are notified.
Scheduling
Reactions go into a Set: many writes in the same tick, one run per reaction — in a microtask, or when a batch() returns.
DOM
Each binding compares the new value with what the DOM already holds and writes only if it changed.
Reactivity lab
This is where a small app built with Ion runs side by side with a map of what happens on every write: the state change, the scheduler's queue, the bindings and effects that run, and the DOM writes. The lab needs JavaScript.
Building this visualization exposed real problems in Ion 1.0: bindings that re-ran on every write to their store, duplicated notifications, a loop detector that never fired. Version 1.1 fixes all of that and gained an official inspector — which is what powers everything you see here.
§08Side projects
Personal and experimental projects, kept apart from professional work. Besides Ion, some are public and some are for my own use.
Demo application
A task list written with nothing but Ion, to validate the framework in a real scenario — two stores, nine computed values, components, effects, a plugin and local persistence.
Architecture study
In progressA simulated financial ecosystem — store, payment gateway, bank and invoicing — for studying payment reconciliation: detecting, classifying and tracking discrepancies across independent sources. Deliberately over-engineered.
Go, Python, PHP and Kafka are planned, not yet implemented.
Web product · MVP
A party calculator built for Brazil. A few questions — type of party, guests, duration, time of day, city and how much the crowd drinks — become a shopping list in the units stores actually sell, like cases, packs and 10 kg bags of ice, with an estimated cost and where each number comes from.
Code not published
Personal-use PWA
An installable app for managing personal finances: monthly bills, income, debts and goals, with a balance projection for the months ahead. A framework-free front end and a Node.js back end with no external dependencies.
Code not published
§09Reading
The books I'm reading now, the ones I've finished and the ones in the queue. A shelf that keeps growing along with everything else.
§10Contact
Tell me what you need: a new system, an integration, an MVP or a system that needs to evolve. Email is the fastest way; I also reply on LinkedIn.
matheusmdev@outlook.com— Write an emailThis form drafts an email with your answers and opens your email app. Nothing is sent or stored by this site.
Project sheet
DraftProblem
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0 of 6 fields
Custom web applications and systems, integrations and automation, MVPs, and consulting to evolve existing systems — the four services described above.
Yes. Much of my experience is evolving systems in use: I modernized a legacy PHP system, integrated enterprise systems and maintained platforms in production. I start by understanding the code and the context before proposing changes.
With a conversation to understand the problem. Then we agree on scope, priorities and next steps — the stages are under “How it works”.
Yes. A small, well-defined scope is often the best starting point; the right size comes out of the first conversation.
Fédon, ou Da Alma - Platão: (ou Da Alma)
Platão
Edipro · 2016
A Biblioteca da Meia Noite
Matt Haig
Bertrand Brasil · 2019
Que é isto - a filosofia? - Ed. Bolso
Martin Heidegger
Vozes De Bolso · 2018
A Metamorfose
Franz Kafka
Principis · 2019
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