SENIOR SOFTWARE ENGINEER

Building scalable backend and distributed systems with pragmatic cloud solutions, focused on performance, cost efficiency, and real business outcomes.

Nearly 18 years in IT, designing and delivering enterprise software, modernizing legacy platforms, and building cloud-native applications with Node.js, TypeScript, AWS, and modern engineering practices.

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Cristian Fernandes

About me

I'm Cristian, a Senior Software Engineer passionate about building scalable backend systems and pragmatic cloud solutions that solve real business problems. I enjoy transforming complex requirements into simple, reliable, and maintainable software while balancing performance, operational costs, and long-term scalability. My engineering approach is guided by pragmatic architecture, clean design, observability, and continuous improvement, always choosing the right solution for the business rather than the most fashionable technology.

  • Fast, high-quality delivery supported by testing and engineering best practices
  • Clean, scalable architectures: modular monoliths and microservices
  • Cloud optimization: cost reduction, performance tuning, and reliability improvements
Stack
Node / TS AWS Terraform Kubernetes Docker GitHub Actions PostgreSQL Redis Next.js

Featured Projects

All on GitHub

Conveyor

Flagship · Full-Stack

Full-stack event-driven platform with a live ops console: a NestJS API and resilient worker over SQS/SNS (DLQ, circuit breaker), observable end to end in a real-time Next.js dashboard.

  • NestJS • Next.js • TypeScript
  • SQS/SNS • DLQ • Real-time console
Code

Resilient Tetris

Live demo · Resilience

A playable game whose leaderboard survives its own database going down: last-known-good cache, an idempotent score outbox, timeouts and a visible circuit breaker. Break the database yourself and watch a live diagram react.

  • Circuit breaker • Timeouts • Fault injection
  • Outbox • Idempotency • Next.js • Postgres
Break it live

Resilient Node Microservice

Backend · Reliability & IaC

Reliability and infrastructure-as-code: Circuit Breaker (Opossum), fail-fast config (Zod) and structured logs (Pino), provisioned with Terraform and shipped as multi-stage Docker. Load-tested with k6.

  • Opossum • Zod • Pino
  • Terraform • Docker • K6
Code

Event-Driven Order Processor

Backend · Messaging

A focused deep-dive into messaging: At-least-once order processing over AWS SNS/SQS with fan-out, fail-fast validation (Zod), and a Dead Letter Queue with automatic redelivery (maxReceiveCount=3).

  • Node.js • TypeScript • AWS SQS/SNS
  • At-least-once • Fail-fast • DLQ
Code

Experience

From keeping on-premise servers running to designing cloud-native backends. The operations background is why I design for failure first.

  1. 2023 – Present

    Senior Software Engineer, Backend & Cloud

    Dnwest · Independent practice · Remote

    Fixed-term contracts with a defined start and end, run alongside my full-time role. I own the work from system design to cloud deployment. Independent since 2013 and under the Dnwest name since 2023. In 2020 the focus moved from PHP and Java web applications to Node.js, TypeScript and AWS.

    • Before Dnwest: modernized legacy environments with AWS and Docker, cutting infrastructure costs by 30%
    • Multi-tenant SaaS in production for a confidential client: NestJS, Prisma and PostgreSQL behind a Next.js front end, with subscription billing and an access guard that is closed by default, so every new route starts locked
    • Billing engine on AWS Lambda and API Gateway: Pix and boleto through Banco Inter over mTLS, cards through Stripe, and NFS-e issued automatically once payment is confirmed
  2. 2008 – Present

    Software Engineer & IT Infrastructure Specialist

    Grupo Pedramar · Full-time · On-site

    Nearly 18 years responsible for the company's infrastructure, servers, networking and operational continuity, and today also building its internal software. It's where my operational instinct comes from.

    • Sole developer and infrastructure owner: I take requirements straight from the business and deliver them end to end
    • MeuHolerite: payslip portal that splits each store's payroll PDF per employee and publishes it through a queue, with files in a private bucket served only by short-lived signed URLs (NestJS on Railway, Next.js on Vercel)
    • HubCheck: digital pickups at distribution hubs with CPF and invoice validation, a photo of the signed receipt and GPS geofencing for audit, on a low-cost serverless stack (Supabase, Cloudflare R2, Upstash)
    • Multi-tenant expiry and batch control (FEFO) and a BI dashboard on a star schema, with a separate BullMQ worker for asynchronous imports
    • Primary point of contact for incident resolution and disaster recovery on business-critical environments
  3. 2017 – Present

    Full-stack Developer

    Commercial & Industrial Association of Monte Alto · Contract

    Client since 2017. A public platform serving about 35k visitors a month, with a focus on performance, UX and security.

    • Query and caching optimization: 30% lower TTFB and 45% longer average time on site
    • Rebuilt the site in Next.js, replacing the PHP platform that had been live for years
  4. 2024 – 2025

    Back-end Developer

    River Trading · Contract

    Modernized internal services in a high-demand corporate environment, focused on latency, performance and observability.

    • Improved responsiveness and resilience of Java / Spring Boot services
    • Standardized CI/CD pipelines and deployment workflows
    • Introduced structured logging, metrics and monitoring

What I do

Architecture & Scalability

Resilient APIs, messaging systems, caching strategies, observability, and Cloud-Native architectures optimized for high scale and reliability.

Legacy Modernization

Incremental refactoring, test coverage, CI/CD pipeline implementation, and safe database migrations with Zero Downtime.

Performance & Front-end

High-performance UX for SPAs and SSR: Core Web Vitals optimization, lazy loading strategies, code splitting, asset management, and accessibility (A11y).

Open to senior full-time roles and to focused projects or consulting engagements. Let's talk →

Let's talk

LinkedIn is the fastest way to reach me. I usually reply within a day.

LinkedIn
GitHub
Brazil • Global Remote

Time zone: GMT-3 | Portuguese (native), English (A2, strong technical reading)

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