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Tools

A selection of useful web performance tools.

Tags
Interface

Responsive Images Automator

Responsive images automator helps to build valid responsive image markup.

ImageOptim

A Mac app and web tool to bulk optimise images of all formats. Super useful if you have a large number of assets to optimise at once.

Web Performance Snippets

A curated list of snippets to get Web Performance metrics to use in the browser console.

DNS Trace

A simple online `dig +trace` tool which explains each step in a DNS trace, useful for finding issues with DNS records and TTLs.

Treo Sitespeed

Treo's Sitespeed report is a fantastic view on Google's Chrome Real User Experience Report. It gives an easy interface to analyse your largest contentful paint, cumulative layout shift and more, over a twelve month period.

Resource Hint Validator

The resource hint validator analyses hints in headers and documents, ensuring that you are not using too many and that each is a valid hint.

HTML Size Analyzer

A super quick tool to view what makes up the size of your HTML document.

Lighthouse Metrics

Lighthouse Metrics allows you to quickly run lighthouse tests against a page from multiple regions.

WakamaiFondue

Wakamai Fondue is a font diagnostic tool, invaluable when working with font subsets and variable fonts.

WebPerf Heatmap

This web performance heatmap is generated by comparing filmstrip images from a webpagetest result. This gives a visual indication of when elements are painted to the screen.

CDN Finder

CDN Finder by CDN Planet will run DNS lookups against a domain or all domains on a page to determine which CDNs they are mapped to.

SVGOMG

SVGOMG is the ultimate SVG optimisation tool, providing a graphical user interface to the Nodejs tool [SVGO](https://github.com/svg/svgo).

TinyPNG

TinyPNG is a handy tool to quickly optimise images, including JPGs!

WebPageTest

WebPageTest is the ultimate performance testing tool, allowing you to run simple or complex tests on browsers around the globe.

RedBot

RedBot is a header diagnostic tool, use it to validate response headers like `ETag` and `Vary`.

PageSpeed Insights

Google's favourite tool for measuring web performance, both in a lab setting (using a server and emulated browser) and with field data from the Chrome Real User Experience Report.

YellowLab Tools

YellowLab tools provides an in-depth audit of web performance best practices.

Request Map

Request map plots every request on a web page, showing what connects all of the third-party content.

Qualys SSL Labs

A deep technical analysis of the SSL / TLS configuration of a domain.

DNSPerf Speed Benchmark

DNS is the very first step a browser makes when trying to load a web page. A slow DNS lookup can make initial pageviews slow, DNSPerf's benchmark queries your DNS record from around the world to get a global view on performance.

Font Drop

Font drop is a font diagnostic tool, unfortunately it does not support WOFF2. See Wakamai Fondue for wider format support.

Glpyhhanger

Glyphhanger is an open source font utility belt - use it to create subset fonts.

Performance Proxy

A simple web UI on top of a Cloudflare Worker to dynamically apply optimisations. Useful for testing the potential impact of simple changes without having to change any code.