Lead Ruby Developer

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

Job Type: Contract Pay: $60.00 - $65.00 per hour

Work Location: In person