15 SEO Best Practices for Structuring URLs
#1: Whenever possible, use a single domain & subdomainIt's hard to argue this given the preponderance of evidence and examples of folks moving their content from a subdomain to subfolder and seeing improved results (or, worse, moving content to a subdomain and losing traffic). Whatever heuristics the engines use to judge whether content should inherit the ranking ability of its parent domain seem to have trouble consistently passing to subdomains.
That's not to say it can't work, and if a subdomain is the only way you can set up a blog or produce the content you need, then it's better than nothing. But your blog is far more likely to perform well in the rankings and to help the rest of your site's content perform well if it's all together on one sub and root domain.
this recent Whiteboard Friday on the topic.
#2: The more readable by human beings, the betterIt should come as no surprise that the easier a URL is to read for humans, the better it is for search engines. Accessibility has always been a part of SEO, but never more so than today, when engines can leverage advanced user and usage data signals to determine what people are engaging with vs. not.
Readability can be a subjective topic, but hopefully this illustration can help:
#3: Keywords in URLs: still a good thingIt's still the case that using the keywords you're targeting for rankings in your URLs is a solid idea. This is true for several reasons.
First, keywords in the URL help indicate to those who see your URL on social media, in an email, or as they hover on a link to click that they're getting what they want and expect, as shown in the Metafilter example below (note how hovering on the link shows the URL in the bottom-left-hand corner):
#4: Multiple URLs serving the same content? Canonicalize 'em!If you have two URLs that serve very similar content, consider canonicalizing them, using either a 301 redirect (if there's no real reason to maintain the duplicate) or a rel=canonical (if you want to maintain slightly different versions for some visitors, e.g. a printer-friendly page).
Duplicate content isn't really a search engine penalty (at least, not until/unless you start duplicating at very large scales), but it can cause a split of ranking signals that can harm your search traffic potential. If Page A has some quantity of ranking ability and its duplicate, Page A2, has a similar quantity of ranking ability, by canonicalizing them, Page A can have a better chance to rank and earn visits.
#5: Exclude dynamic parameters when possibleThis kind of junk is ugly:
Most CMS platforms have become savvy to this over the years, but a few laggards remain. Check out tools like mod_rewrite and ISAPI rewrite or MS' URL Rewrite Module (for IIS) to help with this process.
Some dynamic parameters are used for tracking clicks (like those inserted by popular social sharing apps such as Buffer). In general, these don't cause a huge problem, but they may make for somewhat unsightly and awkwardly long URLs. Use your own judgement around whether the tracking parameter benefits outweigh the negatives.
#6: Shorter > longerShorter URLs are, generally speaking, preferable. You don't need to take this to the extreme, and if your URL is already less than 50-60 characters, don't worry about it at all. But if you have URLs pushing 100+ characters, there's probably an opportunity to rewrite them and gain value.
This isn't a direct problem with Google or Bing—the search engines can process long URLs without much trouble. The issue, instead, lies with usability and user experience. Shorter URLs are easier to parse, to copy and paste, to share on social media, and to embed, and while these might all add up to only a fractional improvement in sharing or amplification, every tweet, like, share, pin, email, and link matters (either directly or, often, indirectly).
#7: Match URLs to titles most of the time (when it makes sense)This doesn't mean that if the title of your piece is "My Favorite 7 Bottles of Islay Whisky (and how one of them cost me my entire Lego collection)" that your URL has to be a perfect match. Something like
randswhisky.com/my-favorite-7-islay-whiskieswould be just fine. So, too would
randswhisky.com/blog/favorite-7-bottles-islay-whiskyor variations on these. The matching accomplishes a mostly human-centric goal, i.e. to imbue an excellent sense of what the web user will find on the page through the URL and then to deliver on that expectation with the headline/title.
It's for this same reason that we strongly recommend keeping the page title (which engines display prominently on their search results pages) and the visible headline on the page a close match as well—one creates an expectation, and the other delivers on it.
#8: Including stop words isn't necessaryIf your title/headline includes stop words (and, or, but, of, the, a, etc.), it's not critical to put them in the URL. You don't have to leave them out, either, but it can sometimes help to make a URL shorter and more readable in some sharing contexts. Use your best judgement on whether to include or not based on the readability vs. length.
You can see in the URL of this particular post you're now reading, for example, that I've chosen to leave in "for" because I think it's easier to read with the stop word than without, and it doesn't extend the URL length too far.
#9: Remove/control for unwieldy punctuation charactersThere are a number of text characters that become nasty bits of hard-to-read cruft when inserted in the URL string. In general, it's a best practice to remove or control for these. There's a great list of safe vs. unsafe characters available on Perishable Press:
#10: Limit redirection hops to two or fewerIf a user or crawler requests URL A, which redirects to URL B. That's cool. It's even OK if URL B then redirects to URL C (not great—it would be more ideal to point URL A directly to URL C, but not terrible). However, if the URL redirect string continues past two hops, you could get into trouble.
Generally speaking, search engines will follow these longer redirect jumps, but they've recommended against the practice in the past, and for less "important" URLs (in their eyes), they may not follow or count the ranking signals of the redirecting URLs as completely.
The bigger trouble is browsers and users, who are both slowed down and sometimes even stymied (mobile browsers in particular can occasionally struggle with this) by longer redirect strings. Keep redirects to a minimum and you'll set yourself up for less problems.
#11: Fewer folders is generally betterTake a URL like this:
randswhisky.com/scotch/lagavulin/15yr/distillers-edition/pedro-ximenez-cask/750mlAnd consider, instead, structuring it like this:
randswhisky.com/scotch/lagavulin-distillers-edition-750mlIt's not that the slashes (aka folders) will necessarily harm performance, but it can create a perception of site depth for both engines and users, as well as making edits to the URL string considerably more complex (at least, in most CMS' protocols).
There's no hard and fast requirement—this is another one where it's important to use your best judgement.
#12: Avoid hashes in URLs that create separate/unique contentThe hash (or URL fragment identifier) has historically been a way to send a visitor to a specific location on a given page (e.g. Moz's blog posts use the hash to navigate you to a particular comment, like this one from my wife). Hashes can also be used like tracking parameters (e.g. randswhisky.com/lagavulin#src=twitter). Using URL hashes for something other than these, such as showing unique content than what's available on the page without the hash or wholly separate pages is generally a bad idea.
There are exceptions, like those Google enables for developers seeking to use the hashbang format for dynamic AJAX applications, but even these aren't nearly as clean, visitor-friendly, or simple from an SEO perspective as statically rewritten URLs. Sites from Amazon to Twitter have found tremendous benefit in simplifying their previously complex and hash/hashbang-employing URLs. If you can avoid it, do.
#13: Be wary of case sensitivityA couple years back, John Sherrod of Search Discovery wrote an excellent piece noting the challenges and issues around case-sensitivity in URLs. Long story short—if you're using Microsoft/IIS servers, you're generally in the clear. If you're hosting with Linux/UNIX, you can get into trouble as they can interpret separate cases, and thus randswhisky.com/AbC could be a different piece of content from randswhisky.com/aBc. That's bad biscuits.
#14: Hyphens and underscores are preferred word separatorsNotably missing (for the first time in my many years updating this piece) is my recommendation to avoid underscores as word separators in URLs. In the last few years, the search engines have successfully overcome their previous challenges with this issue and now treat underscores and hyphens similarly.
Spaces can work, but they render awkwardly in URLs as %20, which detracts from the readability of your pages. Try to avoid them if possible (it's usually pretty easy in a modern CMS).
#15: Keyword stuffing and repetition are pointless and make your site look spammyCheck out the search result listing below, and you'll see a whole lot of "canoe puppies" in the URL. That's probably not ideal, and it could drive some searchers to bias against wanting to click.
Best of luck with all your URL creation and optimization efforts! Please feel free to leave any additions, ideas, or observations in the comments below.