Johann Simon Hoffmann

I’m a Software Engineer with 6+ years of experience building and operating business-critical applications, with a strong focus on Ruby on Rails backend development and production systems. I’ve worked with Rails monoliths and microservices, REST APIs, SQL, Sidekiq, AWS, background processing, performance optimization, and production troubleshooting.

At QAT Global, I became the primary engineer for a Ruby on Rails notification microservice supporting transaction notifications in a U.S. financial platform. I delivered new production features, investigated distributed-system failures, and worked on data processing and migrations using AWS, DynamoDB, S3, and Lambda. I also refactored a high-volume batch workflow, reducing the processing time for approximately 200,000 items from nearly 15 minutes to around 30 seconds.

I also contributed to an ExtJS-to-React modernization, delivering five complex tree-based modules designed to handle datasets ranging from hundreds to millions of nodes, while helping establish reusable testing conventions and maintaining 90%+ automated test coverage.

Previously at Ética TI, I built and operated Ruby on Rails MES and traceability systems used across 38 manufacturing plants in Brazil and Turkey. I worked with Sidekiq-based asynchronous processing, REST integrations with SAP, SQL optimization, production incidents, and 24/7 on-call support. I later progressed into a hands-on coordination role, supporting planning, code reviews, task breakdown, and mentoring.

For more than four years, I worked daily in English with U.S.-based engineering teams, participating in technical discussions, refinements, estimates, code reviews, and product demos. I’m particularly interested in backend and Ruby on Rails roles where I can take ownership of production systems, solve performance and reliability problems, and contribute across the full delivery lifecycle.