What is a URL Slug & How to Optimise It For SEO

Author: Maciej Grzymkowski, Content Writer

Some things in SEO can be quite complicated and daunting to deal with when optimising your page, but URL slugs are not one of them. 

With WordPress and most other content management systems (CMS), you can easily edit the URL slug for each one of the pages on your website in a matter of seconds. It’s a quick SEO win that will surely go a long way as far as user-friendliness is concerned. 

But what are they, and why should you care about them in the first place? As you may have already guessed from the title, it’s got something to do with SEO. 

Keep reading to find out what URL slugs are, and why it’s important to put some thought into them. I’ll also take you through some best practices, which will help you consistently put out concise, readable URLs on your website. 

What is a URL Slug?

In the simplest of terms, URL slugs are what go into the final part of any URL linking to a particular page on your website. 

Each page has a unique slug that helps identify it and set it apart from other parts of a larger site. 

There are very few limits as to what you can put in your URL slug. You can freely edit it to say whatever you want in your CMS software, or keep the structure as automatically generated by the program. 

Here is an example of two very different URL slugs: 

❌ www.website.com/blog/3lknl124hli

✅ www.website.com/blog/an-interesting-post-about-seo

Both of these are valid links that will successfully take you to a blog post on a website (don’t actually click them; they’re not real). 

However, one is a random string of letters and numbers that doesn’t tell you anything about the page being linked, while the other contains a clear, short statement of what you can expect to find after following the URL. 

You could probably easily memorise it if you had to.  

This difference is key to understanding the importance of URL slugs in the context of SEO and navigability of your website. 

Why Are URL Slugs Important For SEO? 

According to Google’s John Mueller, the leading authority on all things SEO-related, the URL slug is a “very, very lightweight factor.” 

In other words, the search engine’s crawlers take it into account before they index a page, but that’s about the only instance where it matters for the algorithms. 

In Mueller’s own words, “if this is the absolute first time we see this URL [and] we don’t know how to classify its content, then we might use the words in the URL as something that helps us rank better.” 

The entire conversation with Mueller where he addresses URL slugs, along with other useful SEO knowledge, is available on YouTube. 

User-Friendliness Above All 

So URL slugs don’t play a major role in how your pages rank on search engine results pages (SERPs). That must mean that you don’t really need to worry about making them coherent and readable, right? 

Not exactly. Search engine algorithms are one thing, but the most important factor when it comes to URL slugs is the user experience. 

Imagine receiving a poorly-optimised link via email or an instant messenger, with an overly long slug that contains a string of random characters. It doesn’t tell you anything about its content, and if you’re particularly mindful of your online security and privacy, it can be a major red flag, deterring you from following the link at all. 

Now consider a URL with a well-thought-out, informative and descriptive slug that tells you exactly what you can expect from the page it’ll take you to. Without any confusion or mystery about the contents of the link’s final destination, people are much more likely to follow it. 

Furthermore, descriptive slugs that let you know what lies on the other side are easy to remember, and increase the likelihood of the link being shared to more people. 

By striving to keep your links as user-friendly as possible, you’re making it easier for viewers to spread the word about your website via link sharing, as well as allowing people to head to pages that are of particular interest to them on a whim, by simply typing out the URL in their browser. If you optimise the slug correctly, it should be almost as easy as googling it! 

URL Slug Best Practices

The key thing to remember when drafting your URL slugs is to make them as descriptive or informative as possible. With that said, there are still some things to be wary of when writing them, which will help you maximise their usefulness and user-friendliness.

Keep Them Clear & Concise 

While each and every URL slug you create should describe your pages’ contents to give users an idea of what to expect, it doesn’t mean you should turn them into long, verbose sentences that paint a vivid picture of your blog post or landing page. Ideally, you should fit the main gist of your content in five words or less. 

Let’s take this article as an example. There are quite a few ways to go about writing a URL slug for it. Here’s two: 

❌ www.susodigital.com/blog/what-is-a-url-slug-and-how-to-optimize-it-for-seo 

✅ www.susodigital.com/blog/optimising-url-slugs-for-seo 

Both links give readers a clear idea of what they’re going to learn from this blog post, but the first one, a word-for-word copy of its title, contains way too many unnecessary words, making it difficult to remember, and even harder to type from memory. 

The latter one, “optimising-url-slugs-for-seo,” on the other hand, sends virtually the same message in 5 words, as opposed to 12. 

Be Descriptive

As you strive for simplicity and conciseness in your slugs, don’t forget about the informative factor. 

Create URL slugs that will give a clear idea of your content even to people who are unfamiliar with your brand and niche. 

Let’s take a look at another way to phrase the slug for this article, this time using one word only: 

❌ www.susodigital.com/blog/slug 

Those with basic SEO knowledge might infer that the link will take them to a blog post about URL slugs. If they’re familiar with SUSO as a company, they might even figure out that it contains some useful SEO tips. 

But what if the user is someone who’s never heard of SUSO Digital and doesn’t know what “SEO” stands for? For that person, this URL might pose more questions than answers. Is this a link to a post about slimy molluscs? Is SUSO Digital the website of a slug farm that advertises itself online? Maybe the link will take me to a browser game that’s a “Snake” rip-off? It might sound silly, but that’s only because you’re well into this article and know what it pertains to. 

Instead, it’s better to give users some more information to help them form better assumptions. Here are some examples of a short, yet descriptive slugs for this blog post: 

✅ www.susodigital.com/blog/url-slugs-definition-and-tips

✅ www.susodigital.com/blog/url-slugs-and-seo 

✅ www.susodigital.com/blog/what-is-a-url-slug

All of the above URLs give the viewers a better hint about what they’ll see after following the link. They’ll know the page is about “URL slugs,” not the gooey animals, and they’re likely to figure out that they’re about to read some tech-related content. 

Separate Words With Hyphens, Not Underscores

URLs that use hyphens to separate words are easier to read to humans than those that utilise underscores, especially in the tiny bar of an internet browser. 

Google itself also recommends you to choose hyphens in its URL Structure guidelines, where they suggest that their crawlers identify hyphens as word separators, which is not necessarily the case with underscores. 

So, to fully optimise your URLs for SEO and avoid confusing your users, write slugs that look like this:

✅ www.susodigital.com/blog/url-slugs-and-seo

… instead of ones that look like this: 

❌ www.susodigital.com/blog/url_slugs_and_seo

Avoid Including Dates to Make It Future Proof 

Always strive to make your URLs as evergreen as possible, i.e. retaining relevance well into the future. 

Do so even when your content is date-specific. That way, if you ever update your article, all you’ll have to do is replace the content while keeping the same URL. 

Let’s say you run a blog about cars and you’ve published a review of the best phone mounts in 2023. That article is likely to lose relevance next year, as new mounts get released. Thus, there will be little reason for people to visit the 2023 article. 

Updating that page to be relevant in 2024 with a date-specific slug, such as the following will be confusing to both users and web crawlers. 

❌ www.carlover.com/best-phone-mounts-2023

Instead of creating a new page with all the work that goes into it, you can simply use a future-proof slug, which in this case, just entails removing the year from the URL: “

✅ www.carlover.com/best-phone-mounts

That way, you’ll have a neat, useful URL you can keep updating for the years to come. 

It also means that you won’t have to worry about implementing any redirects, serving 404 pages and updating any internal/external links to the page.

Use Lowercase Characters

More often than not, URLs are treated as case-sensitive. This is why you should always stick to lowercase letters in your URL slugs. Otherwise, if someone types the URL of one of your pages into their browser without thinking of the proper casing, they won’t reach your site. 

✅ All-lowercase URL slug: www.susodigital.com/blog/url-slugs-and-seo 

❌ URL slug with uppercase letters: www.susodigital.com/blog/URL-Slugs-And-SEO 

Avoid Using Emojis or Special Characters 

Google’s official guidelines are clear about this: you should not use non-ASCII characters in your URL, if you want it to be as well-optimised as possible. 

This includes emojis, as well as characters from all languages that do not use the Latin alphabet, even if your page is written in one of them.

For search engines, this is mainly important before your page is indexed, but when it comes to user-friendliness, using emojis and special characters in your URL slug can pose more serious issues to your viewers.

In many instances, non-ASCII characters will not display correctly on people’s screens, making it impossible to copy-paste, or type out your link. 

✅ User-friendly URL: www.susodigital.com/blog/what-is-a-url-slug 

❌ User-hostile URL: www.susodigital.com/blog/URL-蛞蝓-是-什么 

Frequently Asked Questions 

What’s the Difference Between a URL and a URL Slug? 

A URL is the body text of the entire link to a page, or its web address. The URL slug, on the other hand, is the last part of that address, which serves as a unique identifier of that particular page. 

What Happens If You Change the URL Slug? 

When you change the URL slug of an already-published page without taking the right precautions, you will automatically deactivate the link with the old slug. 

This means that users who’ve saved that address and want to use it to access your site will not be able to do so, and see a 404 error instead. 

The simplest way to keep this from happening is by implementing a 301 redirect, which directs users using an outdated URL to the new address. 

Are URL Slugs a Ranking Factor? 

Google doesn’t consider URL slugs to be a major ranking factor, but it is, in fact, taken into consideration, especially before your site is indexed. Thus, it is safe to say that URL slugs are, indeed, a factor when it comes to ranking your site on SERPs. 

What is the Maximum Length of a URL Slug? 

The maximum length of a URL for most browsers nowadays is 2048 characters. Don’t try to use them all, though! 

Your URL slugs should give readers a hint of the content they’re about to see while using as few characters as possible. In addition, concise URLs are also easier to remember and share.

The Bottom Line 

Optimising your URL slugs is an easy and quick way to improve your website’s navigability and make it more user-friendly. They may not be the most decisive ranking factor, but Google still does take URL slugs into account when crawling and indexing your pages. With how easy it is to do in most CMS software, there really is no reason why you shouldn’t optimise your slugs to be descriptive, informative, and concise. 

If you’re looking to go beyond URL slugs and take your website to the top of search results pages, feel free to check out the chapters in our comprehensive SEO textbook.