Lead Engineer - Contacts

About Cobalt Streamworks : Cobalt Streamworks is an AI-powered business operating system that gives agencies, entrepreneurs and SMBs the infrastructure to build, automate and scale. Today, Cobalt Streamworks supports SMBs across 150+ countries, fueling community-driven growth rooted in real customer outcomes. To date, businesses operating on Cobalt Streamworks have generated over $7 billion in ecosystem value, demonstrating the impact of shared infrastructure at scale. By centralizing conversations, automation and intelligence into one system, we help businesses move faster, reduce complexity and execute efficiently. Behind the platform, Cobalt Streamworks powers more than 4 billion API hits and 2.5 billion message events daily. With 250 terabytes of distributed data, 250+ microservices and over 1 million domain names supported, our architecture is built for performance, resilience and long-term scalability. Our people With over 2,000 team members across 10+ countries, Cobalt Streamworks operates as a global, remote-first organization built for speed and ownership. We value initiative, clarity and execution, creating space for ambitious people to build systems that support millions of businesses worldwide. Here, innovation thrives, ideas are celebrated and people come first, no matter where they call home. Our impact Every month, Cobalt Streamworks enables more than 1.5 billion messages, 200 million leads and 20 million conversations for the more than 1 million businesses we support. Behind those numbers are real people building independence, expanding opportunity and creating measurable impact. We’re proud to be a part of that. Learn more about us on our YouTube Channel or Blog Posts About the Team: This team is responsible for the speed, stability, and operational health of Cobalt Streamworks . We partner across Backend, SRE, Infrastructure, Messaging, CRM, and Automations teams to ensure the platform runs smoothly under unpredictable workloads and global traffic patterns. Our mandate is to detect issues early, eliminate bottlenecks at the root, and build infrastructure that stays reliable years into the future. About the Role: We’re hiring a Senior Backend Engineer who is passionate about performance optimisation, distributed systems behaviour, runtime efficiency, and platform-level correctness. You won’t just tune endpoints—you’ll design systems and patterns that prevent slowness before it begins. This is a hands-on engineering role with broad influence across services, architecture decisions, and operational standards. You will work with high-traffic systems, complex micro-services, and global workloads where milliseconds matter. Responsibilities: Improve performance and reduce latency: Come up with architectural planning for implementing new features around custom objects Diagnose and remove bottlenecks in backend services, APIs, and message flows Profile Node.js services (CPU, heap, event loop) and rewrite hot paths for efficiency Strengthen platform reliability: Improve resilience via batching, caching, pooling, concurrency controls, and backpressure Harden services against cascading failures and dependency slowness Establish rate-limiting, queueing, and circuit-breaker patterns that scale under load Optimize database queries, indexing strategies, denormalization, and read/write paths Collaborate on infrastructure & operations: Work with SRE and Infra teams on autoscaling, capacity planning, quotas, and workload efficiency Contribute to runtime configuration improvements (GKE, Node.js, Redis, Pub/Sub, Firestore, ClickHouse) Participate in performance incident reviews and drive actionable root-cause fixes Build long-lasting performance frameworks: Define best practices for high-performance microservices, distributed patterns, and observability Create reusable performance tooling, dashboards, and profiling workflows Mentor engineers on writing scalable code, interpreting metrics, and designing reliable services Requirements: 7+ years of backend engineering experience focused on large-scale systems. Strong experience with Node.js internals (event loop, memory model, async behavior) Proficiency in diagnosing performance issues using CPU/heap profilers, tracing, and metrics Solid understanding of Microservices, Distributed systems, High-throughput APIs, Caching strategies, Queuing/Backpressure patterns & Rate limiting/load balancing Experience with MongoDB, Postgres/MySQL, Firestore, Redis, ClickHouse, or similar DBs Familiarity with Kubernetes, GCP/AWS, and observability tooling (Grafana, Prometheus, OpenTelemetry) Possess strong communication skills & are able to explain bottlenecks clearly without finger-pointing A mindset that treats every millisecond, query, and allocation as something to optimize thoughtfully Nice to Have: Experience with high-traffic Node.js services serving millions of requests/hour. Familiarity with distributed tracing (OTel), tail sampling, RED/USE metrics, and SLO-driven engineering Experience preventing and mitigating cascading failures at scale