Mateus Lazarus

Senior Full-Stack Product Engineer

[email protected] · https://mateuslazarus.com · São Paulo, Brazil · GitHub · LinkedIn · Website

Open to Relocation to London, UK / Skilled Worker Visa

With over 6 years of software engineering experience, I specialize in operating within highly regulated, high-stakes markets where technical reliability directly intersects with core business strategy. I operate with high agency—owning initiatives end-to-end from strategic planning and domain discovery to technical execution and post-implementation metrics.

Autonomy with Purpose. I value the trust and responsibility to take ownership of complex, ambiguous challenges. I do my best work when I can develop a deep understanding of the business, shape pragmatic solutions, and carry an initiative from discovery through delivery—always with a clear focus on meaningful outcomes.

Engineering Excellence Grounded in the Business. I care deeply about building reliable, thoughtfully designed systems, but I believe technical excellence is most valuable when it is grounded in genuine business understanding. I am at my best in teams that value both engineering craft and domain expertise, using each to strengthen the other.

Thoughtful, Diverse Collaboration. I value working with people from different countries, disciplines, and perspectives who care deeply about their craft and the products they build. I contribute particularly well in collaborative, asynchronous environments where thoughtful communication, mutual trust, and a shared standard of excellence are part of the culture.

Technical Skills

• TypeScript• JavaScript• Node.js• Python• Clojure• ClojureScript• C#• SQL• Next.js• React.js• HTML5/CSS3• TailwindCSS• Angular• Express.js• PostgreSQL• GCP• AWS (EKS, Fargate, Lambda, S3)• Terraform• Docker• Kubernetes• Kafka• Redis• Agentic Workflows• AI Model Context Protocols (MCP)• LangGraph• Claude Code• Gemini Enterprise Agent Platform• Grafana• Datadog• Prometheus• Splunk• New Relic• Playwright• Reqnroll• SpecFlow

Experience

Software Engineer

2025-10 — Present

Nubank — São Paulo, Brazil

Co-founded the Reconciliation team within Global Platforms & Core Banking, operating in an English-first, async international team across 4+ time zones.
Led the end-to-end discovery and architecture for expanding reconciliation pipelines to support global debit products, collaborating directly with cross-functional stakeholders across four countries.
Re-engineered 2 legacy services processing 100M+ daily transactions, achieving 100% observability, refactoring model designs, and enabling automated, real-time tracking of core operational KPIs.
Accelerated engineering throughput across the team to 6–8 PRs per engineer weekly with <1 day review turnaround time by optimizing development workflows.

Software Engineer

2022-04 — 2025-08

Stone Co. — São Paulo, Brazil

Architected high-scale full-stack applications and microservices handling 12B+ annual requests while maintaining 99.95%+ uptime and >95% unit test coverage.
Designed and launched an internal Next.js/TypeScript application for risk analysts, turning a complex 10-page manual workflow into a streamlined UI that cut processing time by 50% and removed user errors.
Provisioned and managed cloud infrastructure using Terraform, Docker, and Kubernetes, implementing CI/CD pipelines via GitHub Actions and Azure Pipelines.
Integrated observability, logging, and data analytics solutions utilizing Datadog, Grafana, Splunk, and Google BigQuery.

Full-Stack Software Engineer

2019-01 — 2022-04

Freelance / Independent Contractor

Delivered bespoke full-stack web platforms using Node.js, TypeScript, React, Express, and PostgreSQL/MySQL for commercial clients.
Built end-to-end CRM and access control systems for Atenas Fit, automating membership monitoring, entry security, and unpaid customer tracking to improve retention and operational efficiency.

Selected Projects

Specialized Risk & Credit Analysis Platform

Led and built an internal web platform for risk analysts using Next.js, TypeScript, and Google Scripts to streamline complex business registration and risk assessment workflows.

Reduced a tedious 10-page, 40-minute manual process by 50%, drastically improving operational agility, user satisfaction, and eliminating human data-entry errors.
Modernized Stone's core risk analysis infrastructure, replacing a legacy monolith with scalable microservices supporting high-value assessments exceeding R$20M (~USD 5M) per evaluation.

Global Core Reconciliation & Operations Platform

Architected and scaled the global reconciliation platform governing Mastercard clearing, settlement, chargebacks, and fee collections across BR, CO, MX, and US, processing 100M+ customer transactions daily.

Improved platform accuracy to reduce annual financial exposure from ~USD 240M to under USD 12K within 12 months, providing executive leadership with near-real-time balances.
Spearheaded company-wide AI adoption by authoring internal AI Model Context Protocol (MCP) guides (+3,350 users, +10,000 views) and hosting hackathons, raising business unit AI engagement from 33% to 86%.

Credit Product Platform & Short-Term Credit

Built and scaled core credit systems from scratch to R$1B+ in portfolio value, increasing capacity from 10K to 1M+ requests per day while maintaining 99.95%+ uptime.

Engineered automated approval and repayment pipelines managing R$50M+ in short-term credit, delivering sub-2-minute customer approvals.

Mateus Lazarus

Technical Skills

Experience

Software Engineer

Software Engineer

Full-Stack Software Engineer

Selected Projects

Spoken Languages

Education & Certifications