Open to opportunities

Washington Pereira User

@washingtonpereirause

Message

I build and scale multi-tenant Rails SaaS backends with measurable performance and reliability gains.

Brazil

Message

What I'm looking for

I'm looking for remote backend or full-stack work where I can own high-impact Rails problems, improve performance and reliability, and collaborate asynchronously with teams that value testing, clear communication, and sound engineering decisions.

At was Advisory, I've optimized Rails applications serving municipalities and high-volume multi-tenant workloads, cutting endpoint latency from 3.5 seconds to 180ms and redesigning a 1.77M-record export from roughly 80 hours to 7 minutes.

I work across Ruby on Rails, PostgreSQL, MySQL, Redis, Sidekiq, AWS, and Kubernetes to solve production problems end to end. I've closed a cross-tenant data exposure issue, built resilient SINAL API integration processing 100k+ records monthly with 99.9% uptime, and delivered tenant-specific fiscal-rule customizations that cut delivery time by 60%.

I've also owned client projects from requirements through deployment, and I build products such as PipelineHQ, BrasilAPI Ruby, and Swarm. I value clear written communication, automated testing, and durable engineering decisions backed by ADRs.

Experience

Work history, roles, and key accomplishments

Current

Full Stack Developer

Current

was Advisory

Aug 2023 - Present (3 years 1 month)

Optimized critical endpoints and PostgreSQL queries, reducing latency by up to 94% and response times by orders of magnitude. Rearchitected CSV export pipeline to asynchronous processing, cutting export time from 80 hours to 7 minutes. Built automated test suites, raising coverage from 35% to 85% and fixing critical data isolation vulnerabilities.