The structure of your site’s URLs has a serious impact on crawlability, SEO, and user-friendliness. A solid SEO will know how to craft effective URLs, but other people who have a direct impact on building your site – developers, IT staff, and management – may not necessarily be in a position to think about how they structure your URLs.

Below, SEO Ethan Hays describes URL best practices that should always be adhered to when creating new, or modifying any existing URL on your domain.

Preferred Format

The preferred format for any URL is one that satisfies the following guidelines:

• Short – Users click on URLs with shorter character counts up to 2x as much as longer URLs
• Static – Static URLs are easier for user to remember and share
• Descriptive – Presence of keywords, separated by hyphens, is beneficial for ranking in search engines, and is easier for users to understand

There will, of course, always be edge cases where URLs cannot conform to the above standards. However, these edge cases must always be explicitly agreed to during SEO review before being released in production.

Best URL Practices

1. ALWAYS 301 Redirect Old URLs to the New, Canonical Version

Search engines are easily confused by multiple URLs that resolve to the same piece of content. For any given page, you want exactly ONE URL that references that content – the canonical URL. All other URLs that may have existed previously, or could be created by an application in the future, should be 301 redirected to the new, canonical URL.

2. Describe Your Content

An obvious URL is a great URL. If a user can look at the Address bar and make an accurate guess about the content of the page before ever reaching it, you’ve done a great job. This issue also addresses search engines. Engines place greater weight on URLs that contain identifiable, descriptive keywords.

3. Static URLs are Superior

Some engines treat static URLs differently than dynamic ones. And from a user’s perspective, it’s more difficult to understand, remember, and tell a friend about a URL with lots of “?,” “&,” and “=.”

4. Fewer Folders

A URL should contain no unnecessary folders (or words, or characters). Ideally, there should never be a URL that resolves from your root domain longer than: http://www.mysite.com/content-type/article-title/

5. Descriptive Folder Names are Better than Numbers, Alphanumeric

Instead of using: http://www.mysite.com114/cat223/
Go with: http://www.mysite.com/galecontent/asthma/

Even if the descriptive folder name isn’t a keyword or particularly informative to an unfamiliar user, it’s far better to use keywords when possible.

6. Hyphens Separate Best

Ordered list of how to separate keywords, in a URL:

1) hyphens are best to separate terms (e.g. http://www.mysite.com/content-type/article-name/)
2) followed by underscores (_)
3) pluses (+)
4) no separation between words

7. Always Use Absolute, Fully Qualified URLs

At your code level, always reference your absolute, fully-qualified URL structure:

Use: a href=”http://www.mysite.com/content-type/article-name/”
Do not use: a href=”content-type/article-name/”

8. Omit File Extensions

They serve no purpose for a search engine, (outside of extensions like .exe), and introduce extra QA and engineering hassle to maintain.

9. Named Anchors Are Only For Inter-page Navigation

URL normalization by engines results in removal of anything after the hash tag (http://www.mysite.com/content-type/article-title#subsection). If you have a piece content that is only findable with a named anchor, make it accessible in other ways.

10. Don’t Pass Through Anything Except Letters, Numbers and Hyphens for any URL

When creating URLs for content pages, we should pass through only letters, numbers, and hyphens: Commas, apostrophes, ellipses, ampersands [,’{}()&] should all be replaced or removed. For applications, more complex URLs are sometimes necessary, and it is the responsibility of your SEO lead to identify any that are potentially problematic.

11. Don’t be Case Sensitive

Since URLs can accept both uppercase and lowercase characters, don’t ever allow any uppercase letters in your URL structure. Any capitalized versions should be redirected to all-lowercase versions. There are edge-cases where capitalization is allowed, but consult with your SEO before implementing.

12. Do Not Append Extraneous Data

There’s no point to having a URL exist where removing characters generates the same content. You can be virtually assured that people on the web will link to you in different ways and confuse themselves, their readers and the search engines with duplicate content issues.

13. Subdomains Should be Avoided, Except for Partner Deals

Never use multiple subdomains (e.g. siteexplorer.search.yahoo.com) – it’s unnecessarily complex. More importantly, subdomains have the potential to be treated separately from the root domain when it comes to passing link authority and trust value.

14. NEVER Pass Session-Level Information in an URL

Session IDs should never be included in a URL. Session-level information should be tracked with cookies.