Cossack Labs
Node.js Engineer
Cossack LabsUkraine3 hours ago
Full-timeRemote FriendlyEngineering, Information Technology

This position is open exclusively to Ukrainian residents within Ukraine (preferably Kyiv).

We’re looking for a Senior Node.js Engineer to build and evolve our web platform, with a primary focus on Node.js, React, and PostgreSQL development.

Main responsibilities:
  • Contribute the majority of your time to product development: design, implementation, and testing.
  • Deliver high-quality Node.js services and React UI changes; write maintainable, well-tested code.
  • Design SQL beyond ORM abstractions; analyze queries, optimize performance, and evolve schemas.
  • Improve reliability by creating runbooks, post-incident reviews, and automation for recurring tasks.
  • Own rapid first response during business hours via instant messenger and an emergency phone line.
  • Triage, reproduce, and diagnose issues across the stack; restore service quickly where possible.
  • Apply safe workarounds, configuration tweaks, or hotfixes; execute rollbacks when needed.
  • Escalate efficiently to the development team with clear context, logs, impact, and proposed next steps.
  • Communicate status and timelines to internal stakeholders and customer contacts.
  • Enhance monitoring and alerting; instrument services for actionable logs, metrics, and traces.
Requirements:
  • Senior-level experience building production Node.js applications.
  • React familiarity for practical UI issues diagnosis.
  • PostgreSQL expertise and strong SQL skills beyond ORM usage, including query design and tuning.
  • Hands-on experience with incident triage, root-cause analysis, and production debugging.
  • Comfortable with Linux servers and on-prem fundamentals (DNS, TLS, certificates, basic networking).
  • Proficient with Git workflows and CI/CD practices.
  • Familiarity with observability (logs, metrics, traces) and structured troubleshooting.
Nice to have:
  • Python or Go experience for tooling, services, or automation.
  • Solid understanding of Docker for local development and packaging.
  • Knowledge of reverse proxies/load balancers (Nginx, HAProxy, Traefik).
  • Exposure to container orchestration (Docker Swarm or Kubernetes) and IaC (Terraform/Ansible).
  • Practical experience in diagnosing infrastructure problems: resources congestions, network connectivity issues, PKI and other protocol-level security problems.
  • Experience with Sentry, Prometheus/Grafana, ELK/OpenSearch, or OpenTelemetry.
Hiring Process:
  • Resume review — up to 5 business days.
  • Introductory meeting with the Systems/Software Architect.
  • Technical interview with several team members.
  • Background check
  • Offer discussion.
We Offer:
  • Competitive compensation.
  • Hybrid work model: combination of in-office and remote work as needed.
  • Paid vacation — 21 business days per year.
  • Paid sick leave.
  • Exposure to intersecting domains: software development, information security, and cloud/on-prem infrastructure engineering.
  • Experience in mission-critical projects.


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