Evandro Fonseca Junior
Backend Software Engineer | Node.js · NestJS · TypeScript · Python · PostgreSQL
I build reliable backend systems, APIs and integrations, with hands-on experience taking products from technical discovery and architecture through implementation, testing, deployment and production support.
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About me
I'm a backend developer with 5+ years of software experience and a long-standing background in hardware and infrastructure. That combination helps me investigate problems beyond application code and design for reliability from the start.
In the projects under my technical responsibility, I have made architecture and implementation decisions end to end: understanding business goals, choosing trade-offs, modeling data, building APIs, automating tests and delivery, and following the system in production. I value simple solutions, clear communication and ownership without losing the humility to ask, validate and learn.
I'm currently focused on Backend Developer / Backend Software Engineer opportunities where I can contribute with autonomy, responsibility and consistent delivery.
Production work
Some recent professional systems are private, but their architecture and outcomes can be discussed publicly:
- Owned the architecture and delivery of a web, mobile and IoT ecosystem using NestJS, Next.js, React Native/Expo, TypeScript, Python and PostgreSQL.
- Designed a modular NestJS platform with 8+ isolated domains, full OpenAPI documentation, S3-compatible storage, health checks and automated tests with reported coverage above 80% of lines and 70% of branches.
- Built a reusable offline-first TypeScript SDK with auth, sync, media and transaction modules, including 46+ integration tests, retry/backoff, dead-letter handling and SHA-256 deduplication.
- Implemented an e-commerce search engine with scoring across 7 dimensions, ACID inventory transactions, isolated customer/admin authentication and a layered shipping fallback strategy.
- Collaborated on Angular and Node.js legacy modernization, internal libraries and business-rule implementation at Innovo.
Core stack
| Area | Technologies |
|---|---|
| Backend | Node.js, NestJS, TypeScript, Python, REST APIs, OpenAPI |
| Data | PostgreSQL, SQL, Drizzle ORM, Prisma ORM, SQLite |
| Cloud & infrastructure | Docker, AWS S3, Linux, Cloudflare, CI/CD |
| Quality & security | Jest, Vitest, Playwright, OAuth2, RBAC, JWT, Zod |
| Additional experience | Offline-first systems, IoT/Edge, observability, computer vision, React Native |
Selected projects
PiAgentUI
Desktop and web workspace for AI coding agents, with streaming sessions, MCP and skills panels, terminal, file explorer and a Tauri desktop application. Built with React 19, TypeScript, Vite and Tauri 2.
Gemini Nexus
Multi-account desktop gateway for Gemini and Claude. Provides OpenAI- and Anthropic-compatible APIs, SSE streaming, account switching, traffic observability and encrypted credential storage.
orelhIA
Local and privacy-oriented PT-BR audio transcription server for MCP agents. Built with Python, Docker and Parakeet TDT, with caching, metrics, SSRF protection and automated tests.
NutriScan
Nutrition information platform using Next.js, TypeScript and Prisma. Integrates a collaborative dataset covering 2M+ products and 100+ countries, with advanced filters, layered caching and offline support.
latebra
Self-hosted Python MCP server for private and resilient web access, search and extraction, with layered fallbacks, proxy support, observability and an extensive automated test suite.
Contact
I'm open to backend engineering roles, technical collaborations and conversations about architecture, APIs and reliable systems.
- Portfolio: evandro.dev.br
- LinkedIn: linkedin.com/in/evandrodevbr
- Email: [email protected]
- WhatsApp: +55 47 99274-2365