Lead Ruby Developer - (ActiveRecord, Arel, middleware stack)

VTekis Consulting LLP•Chicago, IL

About The Position

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 transactions Hands-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 queries • replication lag Low-Latency / High-Throughput Optimization • Experience achieving o sub-50ms API latency under load o High throughput using connection pooling, query batching • Hands-on tuning: o Puma workers vs threads trade-offs o kernel tuning (ulimits, TCP tuning) Deep Sidekiq Internals: • Queue prioritization strategies • Dead job recovery • idempotent job design • Redis contention debugging • Sidekiq middleware customization Experience with: • AWS (EKS, RDS, SQS, Lambda) • Docker & Kubernetes • CI/CD pipelines (GitHub Actions / Jenkins) • Observability stack: o Prometheus o Grafana o ELK / OpenSearch • OAuth2 / JWT authentication • PCI-DSS exposure (preferred) • Secure API design (rate limiting, mTLS, encryption) Experience working at: • high-frequency trading firms • payment processors • crypto exchanges • JRuby / TruffleRuby • GraphQL APIs • gRPC services Exposure to: • fraud detection systems • real-time risk engines.

Requirements

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 transactions
Hands-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 queries, replication lag
Experience achieving sub-50ms API latency under load and High throughput using connection pooling, query batching
Hands-on tuning: Puma workers vs threads trade-offs and kernel tuning (ulimits, TCP tuning)
Queue prioritization strategies, Dead job recovery, idempotent job design, Redis contention debugging, Sidekiq middleware customization
Experience with: AWS (EKS, RDS, SQS, Lambda), Docker & Kubernetes, CI/CD pipelines (GitHub Actions / Jenkins), Observability stack: Prometheus, Grafana, ELK / OpenSearch, OAuth2 / JWT authentication
Secure API design (rate limiting, mTLS, encryption)
Experience working at: high-frequency trading firms, payment processors, crypto exchanges, JRuby / TruffleRuby, GraphQL APIs, gRPC services
Exposure to: fraud detection systems, real-time risk engines.