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Job Title:
Lead Ruby Developer
Work Location:
Chicago, IL Onsite
Duration:
12+ Months
Key Responsibilities & Required Technical Expertise:
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
- sub-50ms API latency under load
- High throughput using connection pooling, query batching
- Hands-on tuning:
- Puma workers vs threads trade-offs
- 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:
- Prometheus
- Grafana
- 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
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