LCP
A curated list of web performance metrics, tools, and concepts for measuring page speed and user experience.
What is LCP?
Awesome Page Speed Metrics is a curated repository listing and explaining the key metrics, tools, and concepts for measuring and understanding web performance. It helps developers identify what to measure for page speed and user experience, covering everything from Core Web Vitals like LCP and CLS to network timing and interactivity metrics. The project aggregates official specifications, documentation, and practical implementation guides into a single reference.
Web developers, performance engineers, and site reliability engineers (SREs) who need a reliable, comprehensive reference for web performance measurement techniques and tools. It's particularly useful for those implementing performance budgets or setting up monitoring.
It saves significant research time by providing a well-organized, community-vetted list of performance resources. Unlike generic articles, it offers depth on each metric, distinguishes between lab and field data, and includes practical code snippets, making it a trusted one-stop reference for performance professionals.
Overview
⚡Metrics to help understand page speed and user experience
Use Cases
Best For
- Understanding and implementing Core Web Vitals (LCP, FID, CLS) measurement
- Setting up a performance monitoring strategy with both lab and field data
- Learning the differences between synthetic testing tools like Lighthouse and real-user monitoring
- Finding JavaScript code snippets to measure network performance timings
- Researching the full spectrum of web performance metrics beyond the basics
- Building a performance budget and deciding which metrics to track
Not Ideal For
- Teams needing an integrated, out-of-the-box performance monitoring dashboard with real-time alerts
- Developers seeking automated optimization recommendations or code fixes based on metrics
- Individuals preferring interactive, hands-on tutorials over static reference materials
- Projects requiring custom metric aggregation and visualization without manual tool setup
Pros & Cons
Pros
Covers essential metrics like Core Web Vitals, network timing, and interactivity with clear definitions and measurement contexts, as outlined in the extensive README sections.
Includes ready-to-use JavaScript examples for browser-based measurement, such as calculating DNS latency and TTFB using the Performance API, directly from the network metrics section.
Clearly distinguishes between synthetic testing tools (e.g., Lighthouse) and real user monitoring solutions, helping users choose appropriate data collection methods, as explained in the concepts section.
Aggregates links to official specifications, documentation (like web.dev), and both open-source and commercial tools, saving significant research time for performance professionals.
Cons
Does not provide active monitoring, tools, or implementation guides; users must separately seek out and configure the listed resources for practical use.
While it lists performance tools, it lacks in-depth comparisons, setup tutorials, or recommendations for specific use cases, requiring additional research.
As a GitHub repository, updates depend on manual curation and may not reflect the latest tool changes or metric evolutions without frequent checks by users.
Frequently Asked Questions
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