Frontend Performance

Specialist frontend skill. Produces the three deliverables that give a team an operable performance posture: a budget per critical flow, a measurement plan tied to the SLO set, and a regression gate in CI. Not a generic optimisation checklist.

Prerequisites: Load system-architecture-design (for the critical-flow table) and observability-monitoring (for the SLO set and RUM dashboard conventions) before this skill. Load react-development or nextjs-app-router if the stack is React/Next.

Use When

• Defining the performance budget for a new product or critical flow.
• Diagnosing a field regression on LCP, INP, or CLS captured by RUM.
• Wiring up a regression gate before a team scales frontend merges.
• Auditing an existing frontend and translating findings into budgets and gates.
• Choosing between inline CSS vs deferred, server vs client rendering, or route vs component code-split.

Do Not Use When

• The bottleneck is server latency or database query time — use observability-monitoring, the relevant database skill, or reliability-engineering.
• The work is API contract design — use api-design-first.