Arthur Fileti Fiorette

Senior Software Developer

Senior software developer from Brazil focused on developer tools and platform infrastructure. I like building the surfaces other developers depend on: build and deploy pipelines, public APIs and SDKs, CLIs, code generators and, lately, agent harnesses and MCP servers. TypeScript is most of my stack, with Rust where it pays off. Writing code since 2018, professionally since 2021.

I own problems end to end, from bundler plugin to edge runtime to billing, and treat open source as part of the job: I maintain packages with millions of monthly downloads, contribute upstream to the tools I depend on and co-authored a Stage 0 TC39 proposal. Fluent in English; open to relocation across Europe and the Americas.

Experience

Freelance work and engagements under NDA are not listed.

  • Jul 2024Oct 2026

    Senior Platform Developer @ Zephyr Cloud - USA (Remote)

    Zephyr Cloud is a deployment and release platform for micro frontends and Module Federation. I worked across the whole stack: the build plugins for Vite, Webpack, Rspack, Rollup, Parcel, Astro, Nuxt and other bundlers and the agent they share, the edge engine that serves applications on Cloudflare, Netlify, Fastly, Akamai, AWS and Kubernetes, and the control plane with deploys, rollbacks, environments and integrations into the customer's own infrastructure.

    Drove the platform's engineering infrastructure: migrated the API from NestJS to Hono with an OpenAPI-first contract and a generated TypeScript SDK, moved Nx to Turborepo with remote caching, added per-PR preview environments, supply chain policies and Sentry and OpenTelemetry observability, and set up the team's AI tooling: agent guides, MCP servers and reusable skills and commands.

    TAP is Zephyr's collaborative AI platform: a Tauri desktop app with a Rust core, backed by Cloudflare Workers, Durable Objects, Queues and D1. There I owned the Windows port and the silent desktop updater, identity relocation and realtime recovery in chat, the Polar-based miniapp marketplace, and the signed native distribution of ze-harness, an open source terminal agent harness, through Homebrew and WinGet.

    Led billing on both products: Stripe subscriptions with tiers, seats, yearly cycles, coupons, scheduled changes and multi-organization plans, usage metering through Queues and Durable Objects, 3DS2 authentication, referrals and transactional emails.

  • Apr 2022Jul 2024

    Software Engineer @ Kasco R&D - Campinas, Brazil

    Developed and maintained the backend of a feed management system for large cattle farms, balancing a simple experience for low-tech farmers with the performance needed to run millions of forecasts and calculations.

    Architected the backend with Fastify, Node.js, TypeScript, OpenAPI, PostgreSQL and Kita, an open source framework I created. Built the interfaces with React, TypeScript, Material UI and a typed client generated from the OpenAPI schema.

  • Jan 2021Apr 2022

    Software Developer @ E&L Sistemas - Domingos Martins, Brazil

    Led the development of a COVID-19 vaccine temperature monitoring web application for the state of Espírito Santo and built a fleet vehicle tracking application used by several private companies. Automated the deployment of the company's flagship product, cutting deploys from a day to a few minutes, and added automated tests against its services to catch regressions early.

    Worked with React, TypeScript, Node.js, PostgreSQL, NestJS, Nuxt, WebSockets, Spring Boot and Jenkins, collaborating with several internal teams across projects.

Open Source

I maintain axios-cache-interceptor and prisma-json-types-generator (1.3 million and 1.9 million npm downloads a month), plus the small libraries behind them (try, fast-defer, object-code, cache-parser). Together, the packages I publish see around 9.5 million downloads a month. I also created the Kita ecosystem: a type-safe backend framework for Fastify and @kitajs/html, one of the fastest JSX runtimes for generating HTML.

I co-authored the ECMAScript Try Operator proposal (Stage 0). Upstream, I am a frequent contributor to ts-json-schema-generator and have contributed to Fastify, orval, prisma-kysely, swc-node, pnpm, nixpacks, Stripe, Scalar, Cloudflare and others, mostly around TypeScript types, code generation, Node.js runtime behavior and performance.

More at github.com/arthurfiorette.

Talks

Engenharia além do prompt, or Engineering beyond the prompt (Domingos Martins, Brazil, September 2026): a 40-minute talk on agent harnesses, repository context, tools and MCP servers, and validation in AI-assisted engineering workflows, with a worked example of generating end-to-end tests from recorded browser sessions.

Education

  • 2020-2022

    Technical Diploma in Business Administration

    IFES - Instituto Federal do Espírito Santo

  • 2023-2025 (incomplete)

    Systems Analysis and Development

    IFSC - Instituto Federal de Santa Catarina