Cossack Labs is a British company, headquartered in London, with R&D offices across Ukraine. We support innovators by protecting innovations. Our data security solutions assist businesses of all sizes and industries protecting their sensitive data against external attackers, insider threats, mis-configurations while remaining compliant with regulations.
23 січня 2026 бронювання

Node.js Engineer (вакансія неактивна)

Київ, Львів, віддалено

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.