Software development · Brazil
Systems, APIs and integrations built to last.
I'm Leonardo da Silva, a full-stack developer. Through LDS Tecnologia I build custom systems, APIs and integrations with WhatsApp, payments and AI, using clean architecture and code the next developer can actually maintain.
- years building software
- 3+years building software
- back-end stacks in production: Spring, .NET and Node
- 3back-end stacks in production: Spring, .NET and Node
- from requirements to deploy
- Full-stackfrom requirements to deploy
Services
What I build
From internal systems to integrations that talk to your customers on WhatsApp.
Custom systems
Web applications and internal tools that follow how your operation really works, from data entry to reporting.
APIs and back-end
REST APIs in Java (Spring Boot), C# (.NET) and Node.js, with Clean Architecture, tests and documentation.
Integrations
WhatsApp (official Meta API), payment gateways, Brazilian e-invoicing (NFS-e), certificate authorities and webhooks.
Applied AI
Assistants and automations powered by LLMs and RAG, connected to your company's data and processes.
Front-end
Interfaces in Next.js, React and TypeScript: fast, accessible and easy to evolve.
Infrastructure and CI/CD
Docker, CI/CD, nginx and automated TLS. Deploys ship from a commit, with no manual steps.
How I work
A short process with no surprises
- 01
Understand
Requirements and business rules gathered with the people who use the system, not just the ones asking for it.
- 02
Plan
An implementation plan with scope, risks and acceptance criteria before the first line of code.
- 03
Ship in increments
Small, reviewed and tested increments you can see working at every step.
- 04
Sustain
Monitoring, fixes and evolution. The system keeps running after delivery.
Experience
Where I've built
Sep 2026 · present · Remote
Full-Stack Developer · Space IT
- REST APIs in .NET 8 (C#) with Clean Architecture
- Front-end in Next.js, React and TypeScript
- System integrations and versioned database migrations
- Code review, automated tests and security (OWASP)
Sep 2024 · Aug 2026 · Santos, Brazil
Full-Stack Developer · Dai · Intelligent Assistant
- Back-end in Express.js and MongoDB, front-end in Next.js and Tailwind
- Integration with the Meta platform and WhatsApp providers
- Payments with Stripe and Facebook Conversions API
- AI features with RAG and automations with n8n
Jun 2023 · Aug 2024 · Remote
Software Developer (freelance) · Digital certificate registration authority
- Internal workflow management system in Spring Boot and PostgreSQL
- Domain-Driven Design and Clean Architecture
- Integration with a certificate authority and a payment gateway
- E-invoicing (NFS-e), data migration and CI/CD with Docker
Projects
Open source
A few public projects on GitHub. Client work stays with the clients.
Java
Judicator
Moderation plugin for Minecraft servers, published on Modrinth.
C# · ASP.NET
OpenStore
Point-of-sale back-end built with Domain-Driven Design and Clean Architecture.
Go
authentication-api
Authentication REST API applying DDD and Clean Architecture in Go.
C# · .NET MAUI
TicketsIFSP
Mobile app for event and ticket management, built for IFSP Cubatão.
C# · Windows Forms
OpenStore Desktop
Desktop app for products and sales receipts, powered by the OpenStore API.
Java · Swing
volei-117
Statistics system for volleyball matches and players.
Stack
Everyday tools
- Languages
- JavaC#TypeScriptJavaScriptGo
- Back-end
- Spring Boot.NETNode.jsExpressNestJS
- Front-end
- ReactNext.jsTailwind CSS
- Data
- PostgreSQLMySQLMongoDBRedis
- Infrastructure
- DockernginxGitHub ActionsGitLab CIAzure DevOps
- Messaging and observability
- RabbitMQPrometheusGrafanaOpenTelemetry
- AI and integrations
- LLMsRAGWhatsApp Cloud APIWebhooksn8n
Contact
Have a project in mind?
Tell me the problem you want to solve. I reply personally.
contato@ldstecnologia.com.br