Lukas Reinhart Senior Performance Engineer
Seattle, WA • lukas.reinhart@gmail.com • +1 206-555-0187
Profile Summary
- Senior Performance Engineer with 8 years of experience testing and tuning high-traffic retail and e-commerce platforms across web, mobile app and API traffic, specializing in load testing, JVM profiling and capacity planning.
- Hands-on with load testing (k6, JMeter), profiling (async-profiler, Java Flight Recorder), APM (Datadog, OpenTelemetry), data (PostgreSQL, Redis) and cloud (AWS, Kubernetes).
- Deep expertise in workload models from production traffic, p99 latency budgets, GC and query tuning and performance gates in CI, using the USE and RED methods to find the real bottleneck before a peak event.
- Works closely with service owners, SRE, DBAs and front-end teams in release readiness reviews, peak rehearsals and latency incidents.
- Mentors engineers on reading flame graphs and writing k6 scenarios, runs a monthly performance review with engineering leads, and wrote the team’s peak readiness checklist.
Technical Skills
- Languages & Scripting:
- Java, Python, Go, JavaScript, SQL, Bash
- Load Testing Tools:
- k6, JMeter, Gatling, LoadRunner, Locust
- Profilers & Runtime Tools:
- async-profiler, Java Flight Recorder, pprof, py-spy, Linux perf, G1 and ZGC tuning
- APM & Observability:
- Datadog, OpenTelemetry, Dynatrace, Grafana, Prometheus
- Databases & Caching:
- PostgreSQL, Redis, MySQL, PgBouncer, pg_stat_statements, EXPLAIN ANALYZE
- Cloud, Containers & CI/CD:
- AWS, Kubernetes, Docker, GitHub Actions, Jenkins, Terraform
- Front-End Performance Tools:
- Lighthouse, WebPageTest, Chrome DevTools, Core Web Vitals, Datadog RUM
Education
Work Experience
- Built k6 load, soak and spike suites for the checkout, cart and inventory APIs from production traffic mixes, running the Anniversary Sale rehearsal at 3.5x normal peak and finding 4 breaking points before launch.
- Profiled the order routing service with async-profiler and Java Flight Recorder, removed lock contention on a shared price cache and retuned G1 heap settings, cutting p99 latency from 640 ms to 170 ms.
- Built the peak capacity model in Python from 2 years of traffic and sales forecasts, setting EKS node group sizes and HPA targets so the platform took 4.2x normal traffic on Black Friday without a scaling incident.
- Rolled out OpenTelemetry tracing across 46 services in Datadog APM, with RED dashboards per team, cutting the time to find the slow service in a latency incident from 50 minutes to 9 minutes.
- Tuned the product catalog’s top 25 PostgreSQL queries with EXPLAIN ANALYZE and pg_stat_statements, adding covering indexes, PgBouncer pooling and a Redis read cache, cutting p95 query time from 1.2 s to 140 ms.
- Agreed p99 latency budgets and SLOs for 32 customer-facing endpoints with 14 product teams and SRE, with burn-rate alerts in Datadog, raising monthly SLO attainment from 91% to 99.2%.
- Added k6 performance gates to the GitHub Actions pipelines of 22 services, failing any build whose p95 latency rose more than 10% over baseline, and caught 31 regressions before production in the first year.
- Cut 75th percentile LCP on product pages from 3.4 s to 1.9 s, using Lighthouse CI, WebPageTest and real-user monitoring to find render-blocking scripts and oversized hero images.
- Rewrote 140 LoadRunner scripts for the account and billing APIs in JMeter, running distributed tests on AWS and cutting test licence costs by $180K a year.
- Found a connection pool leak in the app login service during 12-hour soak tests, ending weekly restarts and keeping the service up for 90 days straight.
- Profiled the plan change service in Dynatrace before an iPhone launch weekend, removing 3 N+1 queries and raising sustained throughput to 2,400 transactions a second.