Pagespeed optimization guide

Page speed performance

by Patrick Sexton

Make your pages faster. Common page speed issues and their solutions are discussed and illustrated by Patrick Sexton.

Render blocking CSS

CSS is render blocking and often can not be removed, so how is it optimized?

Render blocking javascript

When javascript is keeping the page from loading as fast as it should, your users wait.

Reduce server response time

Make sure your server is providing your pages quickly to the browser.

Enable Compression / Gzip

Compressing with gzip helps speed up your pages and reduce bandwidth used.

Leverage browser caching

Help browsers "remember" your resources (logo,css, etc.) so it can load faster.

Enable keep-alive

Keep-alive enables the browser to get files without repeated and wasteful server communication.

Minimize redirects

Redirects cause major performance and speed issues. Use with caution.

Critical Rendering Path

The most important concept in all of pagespeed. Make big pages load faster.

Prioritize visible content

Above the fold content optimizations for your users (and your ranking).

Content Delivery Networks

Content delivery networks (CDNs) get your webpage files closer and faster to your users.

Optimize CSS delivery

Your CSS should help your webpage render fast, not slow down your webpage.

Avoid bad requests

Sometimes your HTML or CSS will request a resource like an image or a html file that doesn't exist.

Defer loading javascript

Until your javascript is downloaded your page won't display unless you defer it.

How a webpage is displayed

An overview of how a webpage is retrieved and displayed in a browser. Touches on the request, response, build, and render.

Avoid CSS @import

The @import method of retrieving CSS files affects your page speed and should not be used.

Minimize DNS lookups

As a webpage becomes more feature-rich it often uses more DNS lookups which makes it render much slower.

Optimize style / script order

Style tags and calls to stylesheets should be placed before your scripts. If you do this your pages load faster.

Combine external javascript

Combining javascript allows page to load faster by requesting less files.

The .htaccess file

The .htaccess file controls enables a webmaster to control many page speed issues from one file.

Combine external CSS

Combining css files allows page to load faster by requesting less files.

Minify CSS

No matter how you use your CSS, smaller is better and will help your webpages load faster.

Deferring Images

A way to defer images without using jQuery or lazy loading.

CSS image sprites

Combining small images into one bigger one means the page needs to load less to render.

Inline small CSS

Inlining CSS is just putting your CSS into your HTML file instead of keeping it as an external CSS file.

Web font option

Finding the fastest way to deliver your web fonts to your users.

Inline small JS

Inlining JS is just putting your javascript into your HTML file, not an external JS file.

Defer videos

Videos from Youtube, Vimeo and other sources can be deferred using this simple method.

Time to first byte - TTFB

Learn what TTFB is and how to optimize it to be faster.

Defer multiple javascripts

Most webpages need to defer many things, but most articles only show how to defer one thing. Learn how to defer just about anything here.

Base64 image encoding

Smaller images can be inlined into the html to save requests and round trips, rather than downloading each image.

Page interaction point

Optimize for the pages core functionality. Let the user do they want as soon as possible.

HSTS

HTTP Strict Transport Security can be used to remove the redirect needed for secure sites from http to https.

Intro to HTTP

An introduction to HTTP. Understanding how HTTP works can help your pages perform better.

First View

The first view performance metric replicates the experience of a user encountering a webpage for the first time.

Cache-Control guide

Using Cache-Control to leverage browser caching provides a great set of advantages over other methods.

Critical CSS calls

Serving critical CSS files from the same domain as your HTML file can save precious time.

Use less external CSS files

Reducing the amount of external CSS files means your pages load faster and your server functions better.

Call CSS first

Calling CSS files first helps to ensure the browser gets it faster.

TCP slow start

TCP slow start restricts how much data may be initially transmitted over a connection, then increases that capacity methodically.

Web performance glossary

Glossary of web performance metrics and terms.