Matheus Krisciumas
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Software engineer turning ambiguous problems into reliable products .

I build full-stack systems with product sense—focused on clarity, maintainability, and the business problem behind the code. Remote, based in Brazil.

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Matheus Krisciumas

Hi, I'm Matheus.

I'm a software engineer who works on business and ecommerce workflows. I like understanding the problem first, then building systems that stay simple to reason about as they grow.

I care about clear communication, reliable delivery with teams, and tying technical decisions to real business value—not just shipping code for its own sake.

Outside of work, you'll find me playing guitar, staying consistent with fitness, and spending time with friends. That balance keeps me grounded and focused.

Node.js / APIsTypeScriptFull-Stack Product WorkSystems DesignEcommerce Workflows

Work Experience

Jan 2025 — Present

WITEK

Full-Stack Developer

Performance and stability ownership on a legacy property-map platform used by Brazilian notary offices.

  • Refactored critical queries and routes, cutting map load time by ~50% and eliminating peak-time outages.
  • Built a UTM-to-WGS84 coordinate conversion system to standardize geospatial data and improve map accuracy.
  • Adapted quickly to an undocumented PHP/JS codebase, contributing autonomously while collaborating on trade-offs.
PHPJavaScriptPerformanceGeospatial

Sep 2024 — Present

DBKZ

Full-Stack Developer

Sole full-stack developer on a business-critical medical billing system processing R$1.5M/month across 74 hospitals.

  • Owned system design, cloud organization, and SQL data modeling for a product handling 25,000 payment parameters and 4,000 procedures.
  • Built and maintained the NestJS API, React Native app, and Next.js web application end to end.
  • Integrated third-party services for boleto payments, email, WhatsApp, file uploads, and user analytics.
NestJSNext.jsReact NativeSQLCloud

Jan 2024 — Dec 2024

Refmed

Full-Stack Developer

Built a healthcare patient-referral product from zero across mobile, web, API, and database layers.

  • Designed and shipped React Native, Next.js, and tRPC/Prisma API from scratch with senior mentorship.
  • Modeled the SQL database and integrated PIX payments, email, WhatsApp, uploads, and event-based analytics.
  • Implemented realtime chat using Firebase to sync information between clients.
Next.jstRPCPrismaReact NativeFirebase

Feb 2023 — Jan 2024

Keiken

Full-Stack Developer

Backend ownership for money-movement workflows across partners, clients, and associated companies on a benefits marketplace.

  • Built async money-movement flows with Spring Messaging and cron jobs processing ~R$120k/month.
  • Learned Java and Spring Boot independently to maintain and extend the backend API.
  • Developed automated tests with JUnit and complex queries with QueryDSL.
JavaSpring BootAsync EventsQueryDSL

Aug 2022 — Dec 2022 · Freelance — Built single-page applications on demand.

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Matheus Krisciumas