Regras para otimizar a performance de sites web

As 14 regras, segundo Steve Souders (Chief Performance Yahoo!), para otimizar o desempenho de sites web:

• Rule 1 – Make Fewer HTTP Requests
• Rule 2 – Use a Content Delivery Network
• Rule 3 – Add an Expires Header
• Rule 4 – Gzip Components
• Rule 5 – Put CSS at the Top
• Rule 6 – Move Scripts to the Bottom
• Rule 7 – Avoid CSS Expressions
• Rule 8 – Make JavaScript and CSS External
• Rule 9 – Reduce DNS Lookups
• Rule 10 – Minify JavaScript
• Rule 11 – Avoid Redirects
• Rule 12 – Remove Duplicate Scripts
• Rule 13 – Turn Off ETags
• Rule 14 – Make AJAX Cacheable and Small

A otimização do Front-End é o fator chave para um alto desempenho:

There are three main reasons why front-end performance is the place to start.

1. There is more potential for improvement by focusing on the front-end. Cutting it in half reduces response times by 40% or more, whereas cutting back-end performance in half results in less than a 10% reduction.
2. Front-end improvements typically require less time and resources than back-end projects (redesigning application architecture and code, finding and optimizing critical code paths, adding or modifying hardware, distributing databases, etc.).
3. Front-end performance tuning has been proven to work. Over fifty teams at Yahoo! have reduced their end-user response times by following our performance best practices, often by 25% or more.

Our performance golden rule is: optimize front-end performance first, that’s where 80% or more of the end-user response time is spent.