git:20260529.7c05904 to git:20261004.4b0ddb9

---

name: browser-required

description: "Use when auditing slow page loads, heavy assets, or rendering delays related to Perform browser-based performance audits. Verify the actual bottleneck in DevTools, Lighthouse, or field data before recommending changes."

metadata:

category: performance

priority: medium

difficulty: intermediate

estimatedTime: "10"

source: frontendchecklist.io

---

# Perform browser-based performance audits

Static analysis alone cannot simulate the complex rendering, script execution, and layout processes of modern web browsers, which is essential for capturing real-world performance.

## Quick Reference

- Use real browser engines to capture runtime metrics (LCP, CLS, INP)

- Synthetic tests in full browsers reveal execution bottlenecks

- Verify performance across different device and connection simulations

## Check

Ensure that performance audits are conducted in an environment that executes JavaScript and renders the page (e.g., Lighthouse, Puppeteer).

## Fix

Integrate browser-based testing tools like Lighthouse or WebPageTest into the development workflow and CI/CD pipeline.

## Explain

Explain the limitations of static analysis for performance and why a full browser environment is necessary.

## Code Review

Review the routes, assets, and loading behavior that affect Perform browser-based performance audits. Flag exact files, requests, or rendering steps that add unnecessary network, CPU, or layout cost, and describe the measurement method used to confirm the issue.

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For full implementation details, code examples, and framework-specific guidance,

see `references/rule.md`.