Custom software engineered to automate operations and scale.
I design and build custom software that helps businesses automate operations, manage inventory, sell online, integrate payments and scale confidently. From architecture to deployment, I deliver production-ready solutions.
The core problem
Spreadsheets work until the day they stall your
growth.
Many companies grow before building proper controls. Volume increases, data gets scattered, closing becomes heavy, and business owners don't just suffer from a lack of technology. They suffer from a lack of visibility.
Orders lost on WhatsApp
With too many conversations happening at once, orders slip through the cracks.
No customer control
Contracts, billing, and status updates are scattered across different tools.
Operational errors
Manual rework hurts execution speed and creates avoidable losses.
Fear of growth
Growing with manual control only increases operational chaos.
Your ecommerce doesn't connect to your ERP?
Your store sells, but the operation breaks down after the sale. Orders land in one place, inventory lives in another, and someone has to copy information back and forth every day.
Orders land in one place, inventory lives in another
Your ecommerce connects directly to your ERP. Orders sync automatically, no manual copying.
When a sale happens, inventory doesn't update
Stock updates in real time across both systems. No overselling, no stale numbers.
When stock runs out, the store keeps selling
Inventory levels stay in sync. Products go out of stock automatically when they should.
Someone has to manually sync orders and stock every day
Sync runs on its own. Your team stops copying data and starts working on what matters.
At month's end, the numbers don't match
Orders, inventory, and financials stay aligned. Reports reflect what actually happened.
You don't know what's in stock, what sold, or what's pending
A real-time dashboard shows orders, inventory, and pending items across your whole operation.
What the right service brings to your business
Build software and processes that increase revenue, reduce manual effort, and help your business grow with confidence.
More sales
Turn your digital experience into a conversion engine with clearer journeys and better product engagement.
Less manual work
Automate repetitive processes so your team can focus on delivering value rather than managing spreadsheets.
Better business operations
Simplify workflows and reduce friction with tools built for the way your business already works.
Faster growth
Get to market faster with scalable systems that support expansion without slowing you down.
Software built around your business
Custom solutions shaped around your needs instead of forcing your team to adapt to off-the-shelf products.
Seamless integrations
Connect payments, ERPs, CRMs and APIs to eliminate manual work and keep your data synchronized.
Main challenge
We restore control to growing companies.
Every project starts from a specific pain point: finance, sales, customer service, billing, metrics, automation, or an entire operation that needs to move beyond improvisation.
Assessment
We analyze your business, processes, current systems, pain points, and risks to identify root causes.
Priority
We define the most critical pain point to tackle first for maximum immediate impact.
First delivery
We build something functional quickly to build trust and give you back control of your operations.
Evolution
With proven value, the system grows with new layers and capabilities to meet your expanding needs.
Stuck with a broken MVP or abandoned codebase?
I audit, refactor, and rescue existing software projects—getting your app stable, performant, and back on track without starting from scratch.
Comprehensive Code Audit
Deep-dive analysis into your architecture, security vulnerabilities, dependencies, and performance bottlenecks.
Refactoring & Bug Elimination
Clean up spaghetti code, fix critical production crashes, and stabilize broken database queries or API routes.
Seamless Takeover & CI/CD
Transition maintenance seamlessly from past freelancers or agencies, establishing modern CI/CD deployment pipelines.
Tailored solutions
Not a spreadsheet. Not a generic platform full of tabs.
Option A
Spreadsheet
Useful to get started, but fragile once operations and demand increase.
Option B
Generic platform
Packed with features, but rarely aligned with your real day-to-day workflow.
MarceloSys
Built around your business
Your process is unique, so your software should be designed for the way you actually operate.
WHAT WE DO
Five services. One team. Zero outsourcing.
SERVICE · 01
Sites coded from scratch — full customization.
No off-the-shelf themes, no Shopify locked into a plan limitation. Modern Next.js, green Core Web Vitals, embedded technical SEO. Online stores with custom checkout, payment integrations, ERP and custom shipping.
- Next.js 16 + React Server Components
- Green Core Web Vitals in Search Console
- Technical SEO built in from the first deploy
- Custom checkout + payment integrations
- ERP integration and custom shipping calculation
- Admin panel to edit content without a developer
Problemas específicos resolvidos com escopo fechado e preço fixo
Empresas perdem vendas e tempo com webhooks quebrados, bugs acumulados, código herdado sem documentação e pagamentos que não sincronizam. Estes pacotes resolvem problemas específicos com escopo fechado, prazo definido e preço fixo — sem contrato longo, sem cobrança por hora, sem surpresa na fatura. Você me conta o que está quebrado, eu confirmo escopo e valor em até 24 horas.
- Atendimento remoto para empresas de Balneário Camboriú, Itajaí, Itapema, Camboriú e todo o estado de Santa Catarina
- Correção de webhook, bugs, auditoria de código e integração de pagamentos com escopo definido antes de começar
- Preço fixo por pacote — você paga pelo resultado, não por hora trabalhada
- Escopo e prazo confirmados em até 24 horas após o primeiro contato
Fixed-price packages
Specific problems. Fixed prices. No surprises.
Pick a package, tell me what's broken, and I'll confirm scope and price within 24 hours. You pay a fixed price, not an hourly rate.
Webhook Fix
Webhook failing? Orders or payments not syncing?
A fixed-price fix for one broken webhook. It starts with a short diagnosis, so you know the cause before anything is changed.
Included
- Root-cause diagnosis of one failing webhook (Stripe, Shopify, Mercado Pago or similar)
- Fix for the defined failure: signature checks, retries, duplicate events, timeouts, configuration
- Tests that cover the failing case
- Short written summary of the cause and the fix, delivered as a pull request
Not included
- Stock or inventory reconciliation
- Backfilling or replaying events lost while the webhook was down (quoted separately)
- Syncing several systems (ERP, accounting, warehouse)
- Unrelated bugs found along the way
What I need from you
- Repository access or a branch
- A failing example event and the provider's logs
- A staging environment, if you have one
2-3 days
Teams with one clearly broken webhook
Bug-Fix Pack
A list of bugs and no time to fix them?
Five hours of focused bug fixing on your existing codebase, spent on the issues you choose.
Included
- 5 hours of bug fixing in a Node, React or Next.js codebase
- Use them across any bugs on your list
- Each fix delivered as a pull request with a short note
- Hours tracked and reported
Not included
- New features
- Bugs that need a major refactor (quoted separately)
- Unused hours after the 2-week window
What I need from you
- Repository access and instructions to run it locally
- A written list of bugs with steps to reproduce
- Someone available to answer questions during the two weeks
Within 2 weeks
Teams with a backlog of known bugs
Code Audit
Inherited code you can't trust?
A clear picture of what's in your codebase, what's risky, and what to fix first.
Included
- Review of architecture, security, dependencies and performance
- Prioritized written report, ranked by impact and effort
- Walkthrough call to go over the findings
- One repository, with size agreed before we start
Not included
- Implementing the fixes (can be quoted after the report)
- Penetration testing or certified security audits
- Infrastructure I don't have access to
What I need from you
- Read access to the repository
- A short overview of the product and known issues
- Deployment notes, if any exist
4-5 days
Founders taking over a project from a previous developer
Payment Integration
Need to accept payments in your app?
Add payments to an existing app, with the webhook handling that keeps orders and subscriptions accurate.
Included
- Stripe Checkout or subscription billing (Mercado Pago on request)
- One checkout flow: one-time payments or subscriptions
- Webhook handling for success, failure and cancellation
- Tests and short setup documentation
Not included
- Custom billing logic (proration, tax, multi-currency)
- Invoicing, refund and dispute workflows
- Admin dashboards or customer portals
- Migrating existing customers or subscriptions
What I need from you
- Repository access and a staging environment
- Your payment provider account and test-mode keys
- Your pricing plans and the checkout flow you want
5-7 days
Apps and stores adding payments for the first time
How it works
Tell me what's broken
Send the details through WhatsApp or the contact form.
Scope confirmed in 24 hours
I confirm what's covered, the price and the delivery date.
I deliver, you review
Work arrives as a pull request with a short written summary.
The fixed price covers the scope described in each package. If your project needs more, I'll tell you and send a separate quote before any extra work starts.
Project Rescue
Did your developer leave or did the project get stuck? We take over existing systems, fix problems, and continue development.
Answers to common questions about working together.
Every project is different, but most custom software projects take between 4 and 12 weeks depending on complexity, integrations and project scope. After our initial call, I'll provide a clear estimate and development roadmap.
Yes. I work remotely with businesses in Brazil and internationally. Communication happens through video calls, email and messaging, with regular progress updates throughout the project.
Yes. I build custom Shopify integrations including inventory synchronization, order automation, payment workflows, ERP integrations, webhooks and API-based automations tailored to your business.
Yes. In many cases, your existing ERP can remain in place while I build modern operational tools around it. This approach minimizes disruption while improving workflows and user experience.
Yes. I design and develop SaaS platforms from MVPs to production-ready products, including authentication, subscriptions, payment processing, admin dashboards and scalable cloud infrastructure.
Yes. I integrate popular payment providers such as Stripe, Mercado Pago, PayPal and other APIs depending on your business requirements.
Often, yes. Depending on your current website, I can integrate new business systems with your existing platform or rebuild only the parts that bring the most value to your business.
Schedule a discovery call
Tell me about your project and let's discuss how custom software can help your business automate operations, improve efficiency and grow.
Available for new projects
Ready to talk?
Tell me a bit about your current challenge. If you prefer a quicker conversation, just click on WhatsApp. If you have documents or technical details, email or the form are ideal.