artur.ninja

Full-Stack Software Developer

Software announces itself when it fails — 3 a.m. pages, mystery bugs, services nobody dares touch. I build products end to end, one hand from database to last pixel, and hand them over quiet enough to forget about.

Based in São Paulo ◈ working worldwideAvailable Q4 2026 ◈ two engagements open

The Craft

Built by one hand, quiet by design.

Most software fails at the seams — where the frontend team's assumptions meet the backend team's reality. Working full-stack means there are no seams to fail: the person shaping the API is the same person consuming it.

Eight years in, my work spans fintech platforms moving real money, developer tools with demanding users, and consumer products where 200 ms of delay is a design flaw. Different domains, one standard: restraint everywhere, precision where it counts.

0yrsIn the field
0Systems shipped end to end
0%Uptime across services I run
Kage · Shadow

The best infrastructure is the kind nobody has to think about.

Yaiba · Blade

One cut in the right place beats ten in the wrong ones.

Kata · Form

The same standard on line one and on line ten thousand.

Selected Work

Three contracts, closed clean.

Each ran from the first schema sketch to production monitoring — one continuous line of responsibility, with no handoffs for things to fall through.

2026

Ledgerline — treasury automation

Multi-currency treasury platform for mid-size exporters. I built the double-entry core, the reconciliation engine, and the dashboard the CFO actually opens every morning. Idempotent by design: replaying a day of webhooks changes nothing.

  • TypeScript
  • Node.js
  • PostgreSQL
  • React
  • AWS
R$ 340MReconciled per year
2025

Sawmill — CI insight for monorepos

Developer tool that traces flaky tests back to the commits that made them flaky. A Go ingestion pipeline chewing through 40 GB of test logs daily, a query layer over ClickHouse, and a frontend where every chart answers exactly one question.

  • Go
  • ClickHouse
  • gRPC
  • Svelte
  • Kubernetes
−62%Time lost to flaky tests
2024

Marchetaria — commerce for makers

Storefront and workshop-management suite for independent furniture makers. Inventory, commissions and payments in one system that a two-person workshop can run without a manual.

  • Next.js
  • tRPC
  • PostgreSQL
  • Stripe
  • Redis
1,900+Workshops on the platform

The Kit

Few tools, kept sharp.

The surface

What people touch

  • TypeScript
  • React & Next.js
  • Astro & Svelte
  • Tailwind, and CSS by hand
  • WebGL & Canvas
  • Accessibility as a spec, not a pass

The weight

What holds it up

  • Node.js & Go
  • PostgreSQL & Redis
  • ClickHouse
  • REST, gRPC & GraphQL
  • Event-driven queues
  • Auth that survives an audit

The watch

What keeps it standing

  • Docker & Kubernetes
  • Terraform on AWS
  • GitHub Actions
  • Grafana & OpenTelemetry
  • Load testing before launch day
  • Docs written for the next dev

The Way

Scout. Plan. Strike. Vanish.

Scout

A short discovery sprint: the real constraint, the real user, the real deadline. You get a written plan with costs before any code exists.

Plan

Schema, API contracts and infrastructure sketched together, so the parts are designed to fit instead of forced to.

Strike

Weekly working software, not weekly slide decks. You click a staging URL every Friday, from week one.

Vanish

Load tests, monitoring, and a handover your team can actually run with. Then I disappear — and stay reachable through the first month of weather.

Artur is the only engineer we've worked with who argued against building something we asked for — and was right. The system he did build hasn't paged anyone in fourteen months.
Marina Duarte ◈ CTO, Ledgerline