Advanced performant Lazy Loader using Intersection Observer API.
A fetching async loader and DOM injection sequencer for performance-minded webapps.
CLI tool and lib to gather performance metrics via Lighthouse. Progressive web metrics at your fingertipz.
A very light solution that uses Ajax and pushState to deliver a faster navigation experience inspired by turbolinks and pjax.
CLI tool and lib to gather results about mobile friendly site using Mobile-Friendly Test API
A Web Performance checklist for web designers.
Measures Performance and Reports to Google Analytics-
BPG (Better Portable Graphics) is a new image format.
Generates a website with perfromance metrics of your website from PageSpeed Insights and dev-perf
Automated tool for improving the quality of your progressive web apps. Run as a Chrome Extension, from the CLI, or used programmatically as a Node module.
The easiest way to measure your performance budget.
SVG based HAR Waterfall Viewer
Optimize CSS delivery by checking for redundancy, validation errors, and following best practices.
Html-Speed is a reverse proxy written in Java. It is used for accelerating performance of websites by improving page load speed and reducing load on webservers. This is achieved by applying front-end ...
Website Performance Battles. Compare two URLs. Who will prevail?
The progressive image loading library for great good! Reduce loading time of page to less than a second on slow connections by loading and rendering nicely blurred micro images on the page while loadi...
The PageSpeed modules are open-source server modules that optimize your site automatically.
Louis is a gulp task that is used to analyze the performance of a website against a performance budget.
Big Rig is an experimental, proof-of-concept system for generating and parsing Chrome's trace files. It has a web app dashboard that will allow you to track performance statistics over time, as well a...
The Timeline provides a complete overview of where time is spent when loading and using your site
The percentages of Chrome page loads (across all channels and platforms) that use the corresponding CSS property
The transparency of PNGs for the file size of JPEGs
How strong is your website?
A modular minifier, built on top of PostCSS. Does more than simple whitespace transforms: custom identifier reduction, z-index rebasing, adjacent selector merging and more.
CSS selectors complexity and performance analyzer
A Grunt Task to Measure and Grade Web Page Performance
Find your way through the performance optimization maze in this NodeSchool workshopper
Performance of ES6 features relative to the ES5 baseline operations per second.
Micro-library for gathering web page performance data. Surf-N-Perf provides a simple to use API to gather User Timing and other important performance data in any browser.
Implement localStorage web font caching in seconds. LocalFont is an online Vanilla JS tool that converts your font family files into a ready to use solution for localStorage web font caching.
Webapp to visualize various stats about your css. Rules, selectors, declarations, unique colors, unique font sizes and specificity.
A free online speed check service including waterfall breakdown and website preview.
An api of endpoints to build charts from WebPagetest results. It runs tests, stores them, and offers endpoints to access the data.
This tool displays how CSS is used on a page. Examines the external and internal use of CSS.
Test a page for common page speed issues.
A performance metric bar with a streaming FPS graph and page timing stats. Timing budgets supported.
lazysizes is high performance, fast (jank-free) and self-initializing lazyloader for images (including responsive images picture/srcset), iframes, scripts/widgets and much more.
Fast, on-demand resizing, optimizing and conversion of high-resolution images. Balances quality with file size. Works with existing storage and CMS solutions.
The fastest Node.js module for resizing JPEG, PNG, WebP and TIFF images. Uses the libvips library.
Find out how much it costs for someone to use your site on mobile networks around the world.
WebPerf IO helps you transform Web Performance into Business Performance.
Gather important web performance data. It runs five times providing a good view on understanding how a web page is loaded. It has been rewritten to pull the latest Navigation Timing API data from Phan...
Minimal monitor for JS Heap Size via performance.memory. Like stats.js but for JS memory.
Discover the percent of unused JS on a page with this simple browser proxy. There are already several tools that tell you the percent of unused CSS on a webpage. But what about unused JS? Well this to...
SVGOMG is SVGO's Missing GUI, aiming to expose the majority, if not all the configuration options of SVGO.
A web performance tool aimed to help developers find critical performance issues
uCSS is made for crawling (large) websites to find unused CSS selectors.
Image optimization for humans. Once you sign in with your Github account, you can optimize all of the images in your repos with a single click. Even large sites with hundreds of images can be optimize...
Free online test to help speeding up heavy web pages
ImageOptim optimizes images by finding the best compression parameters and removing unnecessary comments and color profiles. It handles PNG, JPEG, and GIF formats.
Advanced lossy compression for PNG images that preserves full alpha transparency.
Simple way to collect and look at your website performance metrics quickly, that supports budgeting and adding custom metrics.
GTmetrix is a free tool that analyzes page speed performance.
WebPagetest is used for measuring and analyzing the performance of web pages.
Synthetic testing for web apps, highlighting performance bottlenecks from page structure, content domains or individual resources. Analyze requests by geography, network speed, and resources by type, ...
Next generation web performance monitoring. Rigor’s powerful reporting and diagnostic functionalities allow business and technical users to understand exactly how their applications are performing at ...
Monitor front-end performance. Beat the competition. Get continuous feedback on how your front-end code is affecting the performance of your website.
Performance testing tool for Responsive web designs.
Analyze your CSS in a new way. Consolidate, refactor, and gawk at the 37 shades of blue your site somehow ended up with.
A bookmarklet and Chrome extension to create a front-end performance heatmap of resources loaded in the browser using the Resource Timing API. A browser with support for the Resource Timing API is req...
Bookmarklet to analyze the current page through the Resource Timing API, Navigation Timing API and User-Timing - requests by type, domain, load times, marks and more. Sort of a light live WebPageTest.
Concatenate a set of Web Components into one file.
Bindings for Zopfli compressing lib. Compress gzip files 5% better than gzip.
Inline linked css in an html file. Useful for emails.
A function for loading CSS asynchronously.
Critical extracts & inlines critical-path (above-the-fold) CSS from HTML.
PerfJankie is a tool to monitor smoothness and responsiveness of websites and Cordova/Hybrid apps over time. It runs performance tests using browser-perf and saves the results in a CouchDB server. It ...
Sitespeed.io is an open source tool that helps you analyze your website speed and performance based on performance best practices and metrics.
DareBoost offers performance analysis and monitoring (real browsers). It integrates Google Page Speed, YSlow, W3C validators and its own best practices, with tailor-made tips on specific technologies ...
Convert images to WebP
A CSS redundancy analyzer that analyzes redundancy. csscss will parse any CSS files you give it and let you know which rulesets have duplicated declarations.
Produce images at different sizes for responsive websites.
Performance, covered. Calibre tracks how long your pages take to load, how big or small your pages are becoming as well as browser scroll performance. Janky page? You’ll know about it straight away.
A tool for measuring browser performance metrics (like frame rates, expensive layouts, paints, styles, etc.). For Web pages, Cordova/Phonegap and other Hybrid applications. Metrics are measured while ...
Keep a watchful eye on your css colors.
Automates ImageOptim, ImageAlpha, and JPEGmini for Mac to make batch optimisation of images part of your automated build process.
SVGO is a Nodejs-based tool for optimizing SVG vector graphics files.
Grunt task for Performance Budgeting.
Discover your image weight on the web. Find out the image weight in your pages, compare to the HTTPArchive average and discover what images you can optimize further.
Parker is a stylesheet analysis tool. It runs metrics on your stylesheets and will report on their complexity.
PhantomJS-based web performance metrics collector and monitoring tool.
Merge svgs from a folder.
StyleStats is a Node.js library to collect CSS statistics.
Minify images seamlessly
Because CSS is on the critical path to rendering pages. It must be small! Or else!
Combine matching media queries into one media query definition. Useful for CSS generated by preprocessors using nested media queries.
A game of layout, paint, and composite.
PageSpeed Insights With Reporting. Run mobile and desktop performance tests for your deployed site using Google PageSpeed Insights with tidy reporting for your build process.
Enter a URL to test the load time of that page, analyze it and find bottlenecks.
Make your web pages fast on all devices.
A fast, efficient, and well tested CSS minifier for node.js.
Monitor various website performance metrics over time. ShowSlow graphs the results to help you understand how various changes to your site affect its performance.