What are the responsibilities and job description for the Lead Ruby Developer position at GSDK CONSULTING LLC?
This requirement is with our Client - Fujistu.
we have 8 positions
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
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
Salary : $85