Software engineer building custom systems, apps and integrations. Backend-focused with Node.js, NestJS, TypeScript, Python and PostgreSQL, and hands-on work with AI agents and MCP tooling.
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I build software end to end: understanding the problem, choosing the trade-offs, modeling the data, writing the APIs and the interfaces, testing, deploying and following it in production.
- Custom systems and apps: web applications, mobile apps and internal tools, from discovery to production.
- Integrations: REST APIs, third-party services and IoT devices talking to the rest of the stack.
- Backend engineering: API design, data modeling, authentication and authorization, automated tests, CI/CD.
- AI and agents: MCP servers and agent tooling, mostly local-first and self-hosted.
- Diagnostics: performance, security and maintainability reviews of existing systems.
Five years of software work, with a longer background in hardware and infrastructure, which helps when a problem leaves the application layer. Based in Garuva, Santa Catarina, Brazil (UTC-3), working remotely. Open to backend engineering roles and to technical collaborations.
- PiAgentUI: desktop and web workspace for AI coding agents, with streaming sessions, MCP and skills panels, terminal and file explorer (React 19, TypeScript, Vite, Tauri 2, GPL-3.0).
- GeminiNexus: multi-account gateway for Gemini and Claude that exposes OpenAI- and Anthropic-compatible endpoints, with SSE streaming, usage analytics and credentials kept in the OS keychain (Electron, React 19).
- orelhIA: local PT-BR audio transcription MCP server on Parakeet TDT, with LRU cache, VAD, metrics, SSRF protection and automated tests (Python, Docker, MIT).
- latebra: self-hosted MCP server for private web access, search and extraction, with a three-layer anti-bot evasion pipeline, TLS impersonation, proxy rotation and a pytest suite covering the pipeline, proxy manager and stealth layers (Python, MIT).
- dev-workflows: code review workflows shipped as agent skills, covering frontend, backend, architecture and security with explicit verification steps (MIT).
- nutriscan: nutrition platform over Open Food Facts (2M+ products), with barcode search, Nutri-Score and NOVA filters, multi-layer cache and offline support (Next.js, TypeScript, Prisma). Live demo
- as-servicos: institutional site for an engineering company, with a procedural Three.js scene that follows the page scroll (Next.js 16, React 19, TypeScript).
- cursorAI_install.sh: Bash script that installs, repairs and removes the Cursor IDE on Linux, choosing AppImage, DEB or RPM from the detected distribution and architecture (MIT).
- bthaven: native Windows 11 Bluetooth device and audio hub in C#, developed probe-first, so features land only after the underlying Windows behavior is demonstrated with code (MIT).
Part of my work lives in private repositories. The scope, without the code:
- Backend and integrations for the web and mobile applications that support Apolo Energia's internal routines, including IoT device integration and operations dashboards for renewable energy processes.
- A modular NestJS platform (TypeScript, PostgreSQL, Drizzle ORM) split into 8+ isolated domains, with OpenAPI documentation, S3-compatible storage, health checks and automated tests with coverage thresholds of 80% of lines and 70% of branches.
- An offline-first TypeScript SDK with auth, sync, media and transaction modules, including retry with backoff, dead-letter handling and SHA-256 deduplication.
- E-commerce systems with ACID inventory transactions, separate customer and admin authentication and relevance-ranked product search.
- At Innovo (December 2024 to February 2025): Angular front-end components and Node.js back-end logic over PostgreSQL and MySQL, internal libraries and maintenance of legacy systems.
| Area | Technologies |
|---|---|
| Languages | TypeScript, JavaScript, Python, SQL, Bash, C# |
| Backend | Node.js, NestJS, Fastify, Express, REST APIs, OpenAPI, PHP, Laravel |
| Frontend and mobile | React, Next.js, Astro, React Native, Expo, Tailwind CSS |
| Data | PostgreSQL, MySQL, SQLite, MongoDB, Prisma, Drizzle ORM |
| Infrastructure | Docker, Linux, S3-compatible storage, CI/CD, Firebase |
| Quality and security | Jest, Vitest, pytest, Playwright, OAuth2, JWT, RBAC, Zod |
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: evandrofonsecajunior@gmail.com
- WhatsApp: +55 47 99274-2365