Specifying a width and height for all images allows for faster rendering by eliminating the need for unnecessary reflows and repaints.

Inlining small external CSS files can save the overhead of fetching these small files. A good alternative to inline CSS is to combine the external CSS files.

Correctly ordering external style-sheets and external and inline scripts enables better palatalization of downloads and speeds up browser rendering time.

Compacting JavaScript code can save many bytes of data and speed up downloading, parsing, and execution time.

Compacting CSS code can save many bytes of data and speed up downloading, parsing, and execution time.

Specifying a width and height for all images allows for faster rendering by eliminating the need for unnecessary reflows and repaints.

Compacting HTML code, including any inline JavaScript and CSS contained in it, can save many bytes of data and speed up downloading, parsing, and execution time.

Reduce the load times of pages by loading appropriately sized images.

• Resize image files themeselves instead of via CSS
• Save files in appropriate format depending on usage
• Cost benefit ratio: high value
• Access needed

Removing “broken links”, or requests that result in 404/410 errors, avoids wasteful requests.

Redirections on landing pages add delays to the page load and while the redirections are occurring, nothing is shown to the client. In many cases, redirections can be eliminated without changing the function of a page.

Reduce the size of files sent from your server to increase the speed to which they are transferred to the browser.

• Increase page speed
• Cost-benefit ratio: high
• Access needed to the .htaccess files or server administration files

Enabling HTTP Keep-Alive or HTTP persistent connections allow the same TCP connection to send and receive multiple HTTP requests, thus reducing the latency for subsequent requests.

Inlining small external JavaScript files can save the overhead of fetching these small files. A good alternative to inline JavaScript is to combine the external JavaScript files.

Page load times can be significantly improved by asking visitors to save and reuse the files included in your website.

• Particularly effective on websites where users regularly re-visit the same areas of the website
  Benefit-cost ratio: high
• Access needed
• General guidelines for setting expiries:
• Truly static content (global CSS styles, logos, etc.) – access plus 1 year
  Everything else – access plus 1 week

Minimizing HTTP redirects from one URL to another cuts out additional RTTs and wait time for users.

Moving inline style blocks and <link> elements from the document body to the document head improves rendering performance.

It’s important to serve a resource from a unique URL, to eliminate duplicate download bytes and additional RTTs.

Serving appropriately-sized images can save many bytes of data and improve the performance of your webpage, especially on low-powered (eg. mobile) devices.

All static resources should have either a Last-Modified or ETag header. This will allow browsers to take advantage of the full benefits of caching.

Combining images into as few files as possible using CSS sprites reduces the number of round-trips and delays in downloading other resources, reduces request overhead, and can reduce the total number of bytes downloaded by a web page.

Using CSS @import in an external stylesheet can add additional delays during the loading of a web page.

Fetching resources asynchronously prevents those resources from blocking the page load.

Setting the character set at the server level reduces browser processing.

• Avoid setting it in the meta http-equiv tag
• Reduce page load times
• Cost benefit ratio: high value
• Server access needed

Specifying a character set in a meta tag disables the lookahead downloader in IE8. To improve resource download parallelization, move the character set to the HTTP Content-Type response header.

Most proxies, most notably Squid up through version 3.0, do not cache resources with a “?” in their URL even if a Cache-control: public header is present in the response. To enable proxy caching for these resources, remove query strings from references to static resources, and instead encode the parameters into the file names themselves.

Bugs in some public proxies may lead to compressed versions of your resources being served to users that don’t support compression. Specifying the Vary: Accept-Encoding header instructs the proxy to store both a compressed and uncompressed version of the resource.