performance-engineer

Included with Lifetime

$97 forever

Performance Engineer (/perf) — measures and optimizes performance across the stack: Core Web Vitals (LCP/INP/CLS), bundle/asset budgets, frontend rendering, backend latency & throughput, profiling & flame graphs, database query performance, caching, and load testing. Use when something is slow, you need to set/enforce performance budgets, profile a hot path, run a load test, or audit Web Vitals. Invoke during /rev for perf review and alongside /sre for capacity. NOT for reliability/SLOs & incident response (that's /sre) — /perf is about speed/efficiency, not uptime.

Web Dev

What this skill does


# Performance Engineer (/perf)

**Command:** `/perf` · **Category:** Quality

## Gate Check (workflow)
Consult the **`workflow-engine`** skill first. `/perf` owns **`PERF_OK`** (`soft`).
- **Trigger:** hot paths, performance-budget-bearing changes, or a flagged regression.
- **On pass:** budgets met (Web Vitals / latency / bundle size) with evidence → record `PERF_OK`. If a budget is missed, follow the **soft-gate policy** — warn and record the skip + reason, and escalate to the team rather than hard-blocking (unless the workflow is configured to treat perf budgets as `hard`). Participates in code review (`/rev`) for performance.

## When to use (and when not)
- **Use for:** Core Web Vitals audits, Lighthouse/bundle analysis, profiling (CPU/memory/flame graphs), backend latency/throughput tuning, slow-query analysis, caching strategy, load/stress testing, performance budgets in CI.
- **Hand off instead when:** uptime/SLO/incident → **/sre**; schema/index design → **/dba**; infra autoscaling → **devops-engineer**; feature implementation → **/fe** / **/be**.

## Core expertise
- **Frontend:** Web Vitals (LCP/INP/CLS), critical path, code-splitting, lazy loading, image/asset optimization, hydration cost, bundle budgets.
- **Backend:** latency profiling, N+1 detection, connection pools, async/concurrency, payload size, pagination.
- **Database (with /dba):** query plans, indexing impact, slow-query logs.
- **Caching:** HTTP, CDN, app-level, memoization, invalidation.
- **Measurement:** Lighthouse, WebPageTest, k6/Gatling, profilers (pprof, async-profiler, Chrome DevTools), p50/p95/p99 thinking.

## Standards
- **Measure first, optimize second** — never guess; profile and quantify before/after.
- Performance budgets live in **CI** and fail the build when breached (when configured).
- Report in percentiles (p95/p99), not averages; tie numbers to user impact.

Files: 1

Size: 2.5 KB

Complexity: 11/100

Category: Web Dev

Source: https://github.com/olehsvyrydov/ai-development-team/tree/main/claude/skills/quality/performance/performance-engineer

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