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# Evandro Fonseca Junior

**Backend engineer building production systems, integrations, and local-first AI tooling.**

Garuva, Santa Catarina, Brazil · UTC-3 · Remote

**Open to backend engineering roles and technical collaborations.**

[Work](#selected-work) · [Stack](#stack) · [Gitea](https://git.evandro.dev.br/evandro) · [Portfolio](https://evandro.dev.br) · [LinkedIn](https://www.linkedin.com/in/evandrodevbr/) · [Contact](#contact)

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> **Where my work lives now**
>
> My former GitHub account was suspended after one of my repositories was flagged. I take responsibility for the repository: it was a mistake, not bad faith, and I offered to remove it immediately so it could not affect anyone else.
>
> The offer did not change the outcome, and the suspension did not distinguish between the flagged repository and the years of unrelated work around it. I lost access to my personal repositories and to the repositories I maintained for the companies I worked with.
>
> I had backups. The code survived; the account, the issues, the reviews and the history did not. Since then my development operation has been entirely local and self-hosted. **[Gitea](https://git.evandro.dev.br/evandro) is the public door** — the canonical place to find my work, follow what I am building, and collaborate on projects I believe in. If you are hiring or evaluating me, the work below is the evidence; the account that no longer exists is not.

## What I do

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.

| Area | What it covers |
| --- | --- |
| **Custom systems** | 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, 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. That background helps when a problem leaves the application layer.

## Selected work

> Most of these repositories are private. I can walk you through the code, the trade-offs and the production setup in a call.

### AI and developer tooling

- **PiAgentUI** — desktop and web workspace for AI coding agents: streaming sessions, MCP and skills panels, terminal and file explorer. React 19, TypeScript, Vite, Tauri 2.
- **gemini-nexus** — multi-account gateway for Gemini and Claude exposing OpenAI- and Anthropic-compatible endpoints, with SSE streaming, usage analytics and credentials 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.
- **latebra** — self-hosted MCP server for private web access, search and extraction, with a three-layer anti-bot pipeline, TLS impersonation, proxy rotation and a pytest suite covering the pipeline, proxy manager and stealth layers. Python.

### Client and product work

- **[SEV Moda Íntima](https://evandro.dev.br/cases/sev-modaintima)** — catalog, storefront and operations panel for a lingerie brand, with products, orders and stock by size. [Live site](https://sevmodaintima.com.br).
- **[Lavação 047](https://evandro.dev.br/cases/lavacao-047)** — site and admin panel for an automotive wash, with WhatsApp ordering and editable prices, text and photos. [Live site](https://landing-page-lavacao047.vercel.app).
- **[AS Serviços](https://evandro.dev.br/cases/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.
- **[SC Plus Aquicultura](https://evandro.dev.br/cases/sc-plus)** — institutional site with areas, projects and contact for an aquaculture company.

Also: **bthaven** (native Windows 11 Bluetooth device and audio hub in C#), **cursorAI_install.sh** (Linux installer for Cursor that chooses AppImage, DEB or RPM from the detected distribution and architecture), and **dev-workflows** (code review workflows shipped as agent skills for frontend, backend, architecture and security).

## Professional work

> Part of my work lives in private repositories. This is the scope, without the code.

- **Apolo Energia** (since 2022): web and mobile applications, APIs and IoT integrations for the company's internal routines and renewable energy operations, including operations dashboards.
- 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.
- **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.

## Stack

| 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 |

## How I work

- **Own the whole path.** I would rather understand the problem, model the data, write the API and follow it in production than hand off a layer I cannot see.
- **Verify before calling it done.** If I cannot run it, I do not claim it works.
- **Local-first by default.** Local models, local data, self-hosted services and backups I control. Cloud when it earns its place.

## Contact

For backend roles, technical collaborations or conversations about architecture, APIs and reliable systems, use any of these. I work in Portuguese and English.

- **Gitea (canonical):** [git.evandro.dev.br/evandro](https://git.evandro.dev.br/evandro)
- **Portfolio:** [evandro.dev.br](https://evandro.dev.br)
- **LinkedIn:** [linkedin.com/in/evandrodevbr](https://www.linkedin.com/in/evandrodevbr/)
- **Email:** [evandrofonsecajunior@gmail.com](mailto:evandrofonsecajunior@gmail.com)
- **WhatsApp:** [+55 47 99274-2365](https://wa.me/5547992742365)

If you maintain a project you believe in, send me the link. I would rather contribute through Gitea, on infrastructure we can inspect.

*This page is versioned at [evandro/.profile](https://git.evandro.dev.br/evandro/.profile).*