Ruby on Rails Developer

Company Description1ST-RECRUIT LLC is a trusted E-Verified staffing and recruiting company based in Wilmington, DE, specializing in connecting exceptional talent with top organizations across various industries. We provide end-to-end solutions tailored to the diverse needs of IT, engineering, healthcare, finance, and other sectors. As an E-Verified employer, we actively support candidates requiring work authorization, including OPT, STEM, and H1B visa holders. Known for industry expertise, ethical hiring practices, and client-focused partnerships, our mission is to help bridge the gap between talent and opportunity, empowering individuals and businesses to thrive.
Role DescriptionThis is a contract on-site role for a Ruby on Rails Developer, based in Chicago, IL (5 Days Onsite). The developer will work on creating, maintaining, and optimizing back-end systems and front-end user interfaces within a Ruby on Rails framework. Responsibilities will include implementing Model-View-Controller (MVC) architecture, developing and testing scalable applications, and employing Test Driven Development to ensure robust and high-performing solutions. The role will require collaboration with cross-functional teams to deliver high-quality software solutions aligned with project requirements.
QualificationsExpertise:
Strong Expertise with Ruby:• Minimum 12 years of experience on Ruby• Deep knowledge of Ruby MRI internals (GIL, memory model, object allocation)• Ruby MRI garbage collector (mark & sweep, generational GC)• Strong experience with Rails internals (ActiveRecord, Arel, middleware stack)• Ability to optimize slow queries, N+1 issues, and memory leaks• Experience with multi-threaded / concurrent Ruby (Puma, Sidekiq tuning)• Ruby VM instruction set (YARV bytecode basics)• Concurrent Ruby gem• Thread pools vs Fibers vs Ractors• Async frameworks (Falcon / Async gem)• Experience integrating Ruby with Kafka (ruby-kafka / Karafka), exactly-once semantics handling• Designing: event schemas, schema evolution (Avro / JSON schema)
Proven experience scaling Rails apps to:
• 10K+ RPS• millions of daily transactionsHands-on experience with:• Event-driven architecture (Kafka / RabbitMQ)• CQRS & Event Sourcing• Saga pattern (choreography & orchestration)
Strong understanding of:• Eventual consistency• Distributed transactions• Idempotent APIs
Deep understanding of:• Caching strategies (Redis, Memcached)• Background processing (Sidekiq, Resque)• Database sharding and read replicas
Strong experience with:• PostgreSQL (query tuning, indexing, vacuum, locking)• Redis (data structures, pub/sub, distributed locks)
Ability to debug:• deadlocks• slow queriesreplication lag