Full-Stack Developer — based in Brazil. Building production software — SaaS platforms, e-commerce storefronts, serverless data pipelines, and ERP integrations.

I started in Electrical Engineering and ended up deep in software, drawn by the same thing: building systems that work precisely and reliably. I like the parts of the job most people avoid — distributed state, third-party API complexity, schema design that has to survive real-world load.

Curated marketplace of 13 Claude Code skills installable via /plugin marketplace add mqmalagris/claude-skills. Headline is a five-skill feature-delivery pipeline — grill-me → to-prd → compass → heist → maestro — taking a feature from vague idea to merged code, each stage consuming the prior stage's artifact and refusing to proceed on thin context. Also ships code-craft (language/framework idioms across 7 languages and 12 frameworks, with a PostToolUse hook that flips reviewer rules on automatically), a deterministic LLM-first seo audit suite, and OWASP WSTG security testing. All skills use progressive disclosure: a SKILL.md router plus workflows, topics, and reference tables loaded on demand.

Pure-Rust fixed-income library: piecewise linear, natural cubic spline (C² via Thomas tridiagonal solver), PCHIP monotone Hermite, Nelson-Siegel (1987), Svensson (1994) — plus bond pricing (duration, convexity, par yield), compounding and implied-forward-rate conversion, and a zero-dependency date toolkit (ISDA 2006 day counts, business-day calendars incl. Brazil BUS/252, coupon schedules). No third-party numerical crates — bundles its own Nelder-Mead simplex optimizer. unsafe_code = "forbid", post-fit sanity checks with deterministic spline fallback, SLSA Level 3 provenance on every crates.io release.

Local-first, git-friendly API client spanning REST, GraphQL, SOAP, WebSocket, and gRPC in a single TOML collection format — a Postman/Bruno alternative. Dynamic gRPC via .proto reflection with no protoc dependency; JS pre/post-request hooks via boa_engine. CLI-first (pglot) test runner with JUnit/TAP output and CI-correct exit codes, data-driven testing (CSV/JSON), JSON Schema assertions, and snapshot testing — the same engine powers a native egui desktop app. Ships to npm and crates.io with SLSA build provenance.

Flutter chord-pad synthesizer built on the Nashville Number System — tap diatonic pads or twist a joystick to morph chord quality (maj7, sus4, dim, aug). Three instrument engines (SF2 soundfont, pure-Dart subtractive synth, chromatic WAV sampler), a reorderable effects chain (Freeverb reverb, delay, low-pass filter), looper, arpeggiator, and a low-latency 512-frame PCM audio path with a FluidSynth fallback on desktop and web. EN/ES/FR/pt-BR i18n, RevenueCat freemium gate, Android release CD via GitHub Actions.

Go Lambdas + Terraform-managed AWS (SES inbound, S3, DynamoDB with TTL auto-delete, API Gateway, Route53). Astro + Svelte 5 web, React Native + Expo mobile, shared TypeScript API client — all in a Turborepo monorepo. Freemium: 10-minute inboxes free, 60-minute with custom domains on pro.

Public freemium REST + GraphQL API (Indicadores-BR) aggregating Brazilian and international economic data — BCB, IBGE SIDRA, Tesouro Nacional, FRED, ECB — into normalized endpoints with complete history and aggressive caching. Rust + Axum with compile-time-checked sqlx queries, apalis ingestion workers with retry and circuit breakers, real-time PTAX over WebSocket, HMAC-signed webhooks and alerts, and financial calculators (SAC/Price amortization, monetary correction, CDB/LCI/LCA comparison). Yield-curve endpoints are backed by my own yield-curves crate. Single binary on Fly.io; OpenAPI docs and Swagger UI at api.economapy.com/docs.

Languages

Frontend

Mobile

Backend

Databases

Cloud & Infra

Tooling & Testing

B.Eng. Electrical Engineering — CEFET-RJ, Brazil. The engineering mindset stuck: understand the system, find the constraint, fix it properly.

• Email — matheus@malagris.dev