Senior Performance Engineer at N-iX in Ukraine

We are looking for a Senior Performance Engineer to take full ownership of performance, scalability, and stability of our global web-based platform, deployed on-premises or in the cloud and serving thousands of concurrent users worldwide. This is not a project role - performance engineering here is a continuous discipline embedded across the full development lifecycle. You will be the single accountable owner for system performance: setting the standards, building the tooling, enabling teams, and ensuring that as our product complexity, user volumes, and business programs grow, the platform scales predictably and without regression. Responsibilities: Performance Ownership. Define and maintain performance SLAs/SLOs, own system-wide KPIs (latency, throughput, concurrency, stability), and serve as the primary point of accountability for performance across every release Load & Scalability Engineering. Design, implement, and continuously evolve a comprehensive test suite covering load, stress, and endurance/soak scenarios. Model realistic usage patterns specific to our domain - large BOM navigation, product structure queries, search and filtering, change and release workflows and validate scalability for large tenants and peak program conditions Backend & Infrastructure Performance. Analyze and optimize across the full stack: application server behavior (JVM tuning, thread pools, memory management, GC), database query plans, caching effectiveness, and network/storage I/O. Work closely with infrastructure, database, and platform teams to drive improvements Global Performance Optimization. Identify and address regional performance disparities, analyze WAN latency and API behavior for globally distributed access, and contribute to architectural decisions around caching strategies and data locality Tooling & CI/CD Integration. Build and maintain an open-source performance toolchain. Integrate performance testing into CI/CD pipelines, implement automated regression detection, and enforce release gates based on performance criteria Observability & Root-Cause Analysis. Establish and operate observability infrastructure using open-source solutions. Lead deep root-cause analysis on latency spikes, memory leaks, throughput degradation, and long-running stability issues. Support production incidents where performance is a factor Cross-Team Enablement. Partner with development teams to embed performance thinking into design and implementation. Run training on performance anti-patterns and optimization techniques, and deliver actionable insights - not just reports. Requirements: 6+ years of hands-on experience in performance engineering Proven experience with on-premises enterprise systems and cloud environments Strong expertise in web application performance and REST/API performance testing Proficiency in Linux system diagnostics and low-level performance analysis Practical experience with open-source performance tooling: k6, Gatling, JMeter, or Locust Experience with observability stacks: Prometheus, Grafana, OpenTelemetry, Sentry Engineering mindset — capable of building, owning, and evolving systems, not just running tests Ability to operate independently and drive results across teams without close supervision Upper-Intermediate/Advanced English level Nice to have: Background in PLM, ERP, or other large-scale enterprise platforms Experience working with complex data models and large object graphs (e.g., Bill of Materials hierarchies) JVM profiling and tuning experience, particularly for Java-based backend stacks Track record of integrating performance testing into CI/CD pipelines and enforcing automated quality gates We offer*: Flexible working format - remote, office-based or flexible A competitive salary and good compensation package Personalized career growth Professional development tools (mentorship program, tech talks and trainings, centers of excellence, and more) Active tech communities with regular knowledge sharing Education reimbursement Memorable anniversary presents Corporate events and team buildings Other location-specific benefits *not applicable for freelancers