Are URLs Case Sensitive? Best Practices Revealed

In SEO, every detail matters. From dashes, slashes, and spaces to upper and lower cases, all components must be orchestrated seamlessly to compose the ideal rankings and user experience.

In this context, a popular question I often come across in SEO industry forums is:

Are URLs Case Sensitive?

Some parts of a URL (or web address) are case sensitive. In a typical URL, everything after the domain name (or hostname) is considered case sensitive.

These elements are mainly paths, queries, and fragments.

Let’s illustrate that.

Parts Of A URL

A common URL is comprised of the following parts:

URL= scheme: //host /path ?query #fragment

Scheme

The scheme specifies the protocol used to access a resource on the Internet, such as HTTP (without SSL) or HTTPS (with SSL). It is case insensitive.

Host

A host in a URL can be either a registered name (a hostname, like: www.upper-lower.com) or an IP address. Neither are case sensitive.

Path

The path specifies the exact resource on the host that the web client intends to access, such as: /category/products/persian-carpet. Paths in URLs are case sensitive.

Query

If a query string is included, it is denoted by a question mark (?) and placed after the URL path.

A URL query provides a string of information for various purposes, like parameters for extra data or a specific search. These are case-sensitive.

Here’s an example of a URL query when choosing a product’s color variations:

/category/products/persian-carpet/?variant=red

And here’s a search query when looking for a product in an online store:

/search?q=persian+carpet&type=product

Fragment

A fragment in a URL is preceded by a hashtag (#) and contains a fragment identifier that directs to a secondary resource within the primary one. It is a case sensitive element.

URL fragments are used, for instance, to identify a section within an article. For example:

/blog/rugs-carpets/persian-carpets-for-summer#types-and-styles

So, what’s the deal?

For a website and SEO campaign to run smoothly, pay particular attention to your URL character case. Here is why:

Why Case-Sensitive URLs Matter

Search engines and some types of servers treat upper and lowercase URLs differently. This can provoke a series of issues and discrepancies, like:

1. 404 errors
2. Duplicate content
3. Divided page authority and link equity
4. Search engine confusion
5. Indexing discrepancies
6. Analytics data issues

404 Errors Caused By URL Case Sensitivity

Some search engines, like Google, and some web servers, like Apache, are fundamentally case sensitive.

As a result, they treat a single URL with upper-lower case discrepancies like two (or more) different URLs. In cases like this, your website is prone to unexpected 404 errors.

For instance, a user looking for your page: www.example.com/anna-smith - will be served a 404 error when clicking on: www.example.com/Anna-Smith.

But other URL components, like trailing slashes at the end of a URL, matter as well.

My advice? Always pay extra attention to URL spelling, syntax, and structure.

Duplicate Content Due To URL Case Difference

If you are using mixed capitalization for the same URL on your website, Google may index it and treat it as duplicate content, thus downgrading its ranking potential.

For the /anna-smith example above, let’s say there’s an internal link to a news article like:

Last week, <a href=”/Anna-Smith”>our CEO, Anna Smith</a> attended the annual Women in Tech EU summit.

Here, it’s likely that Google indexes both versions of your URL, treating your page as duplicate content.

Divided Page Authority And Link Equity

Common problems with web address case sensitivity include:

a. mixing capitalization when referring to the same URL by mistake, or
b. creating two pages with identical URLs and diverse capitalization.

Either way, both alternatives can be indexed by search engines, dividing page authority and link equity in a lose-lose ranking scenario.

Search Engine Confusion

Search engines attempt to crawl every URL variation they come across, even nearly identical character case URLs. It can therefore take them longer to discover other valuable content on your website.

However, my experience is that this doesn’t really affect rankings.

What does matter is that, if left unguided, search engines must figure out which URL version to keep on their own - oftentimes not your preferred one.

Indexing Discrepancies

Mixing upper and lower casing of the duplicate URLs on your website gets Google mixed up, too!

So, you may face Search Console warnings, low indexing ratio, redundant indexed URLs, etc.

Analytics And Data Issues

Keep in mind that in Google Analytics, different case URL versions appear as different pages altogether - each with its own set of data.

Just filter out your least preferred version to see accurate results.

How To Avoid URL Case-Sensitive Issues?

There are five major issues to consider when it comes to case-sensitive URLs.

1. Your Website’s URLs Are In Mixed-Case Type

Do It Right From Day #1

This is the best way to shield your website’s URLs from case sensitivity issues. Lowercase is the ideal option, so during the development stage, make sure all your page URLs and files are in small letters.

And share this procedure with your team.

Server Configuration

Don’t forget to look into your server’s configurations.

For instance, Apache (case sensitive) servers offer the mod_spelling module that overcomes miscapitalized or slightly misspelled URLs. Linux servers are also case sensitive, while Windows servers are case insensitive.

Platform Settings

Always check your CMS’s default setup on URL case sensitivity and monitor any custom settings that might affect it.

2. Users Typing URLs In Mixed Case: Enforce Redirects

It’s common for returning visitors to write some URLs straight in their address bar. And use syntax-based capitalization.

For instance, if you run a multi-branch store, you may have a URL like:

www.my-store.com/contact/boston - that can often be written as: www.mystore.com/contact/Boston

No matter what, you wouldn’t like users to get a 404. So, it’s always a good idea to set up an .htaccess or server configuration rule to automatically create 301 redirects for mixed-case URLs.

Depending on your platform, there are different workarounds you could follow. Further down this article, I've put together some basic information to get you started.

3. File Names Or Extensions Use Capitals: Lowercase Everything

We’ve all seen it! File extensions, such as ‘.jpg’, are often in capitals - .JPG, for that matter.

What I do in cases like this is turn all file extensions into lowercase before uploading them to a website. This saves me from future problems.

Another good idea is to standardize lowercase for all file names to prevent any issues if the underlying file system is case sensitive.

4. Outbound Links Misspellings: Copy And Paste

Not everyone uses lowercase URLs. So, when inserting external links in your posts and pages, avoid writing or editing them by hand. Always copy/paste them.

5. Robots.txt Rules: Double Check And Test

Just like search engines, your robots.txt file is case sensitive. So, if you want to add a robots.txt rule to prohibit crawling a page like: /lower-case.html

... adding a rule like:

User-agent: *
Disallow: /Lower-Case

... will still allow bots to crawl what you want them to disregard. Again, always copy and paste any URL path you add to your robots.txt.

And always test everything right after implementation.

Best Practices For URL Case Management

Enforcing 301 redirects is the most popular method to avoid mixed case issues. Here’s how to redirect uppercase URLs to their lowercase version:

Enforce Lower Case URIs

Use your server config files to enforce lowercase URLs. If you don’t have access to your httpd.conf file, ask your hosting company to activate the feature.

Here are some resources to help you out:

• Lowercase URIs in Apache
• Enforce Lower Case URLs in NGINX
• Convert URL To Lowercase In IIS
• Add a 404 Uppercase Redirect in Webflow

Note that in WordPress, all uppercase letters are transformed into lowercase by default inside the native slugs. However, you can customize this setting if you need to.

Redirect Using .htaccess

An alternative method to enforce 301 redirects to lowercase is adding a rule in your .htaccess file, if available.

However, the .htaccess solution can be problematic.

So, before implementing any redirects here, remember: Check if your Apache version or other existing rules are likely to create issues like slow speed, broken images, or 500 errors.

If everything looks good, here’s a nice workaround to redirect uppercase to lowercase URLs in .htaccess.

Again, always test your website meticulously after implementing redirects.

Set Up URL Case Redirects From The Start

You never know who will be editing your website or what future implementations you’ll need. That’s why it’s always best to proactively set up these standard redirects before your website goes live.

This is the best way to prevent any future problems or incompatibilities.

Use Canonical Tags

If you already have mixed case URLs indexed, using the rel=canonical tag encourages search engines to focus on your preferred URL.

In cases of distinct pages, consider merging any valuable, non-canonical content to an existing page.

Always Use Lower Case

I can’t stress this one enough. Always use lowercase in your site’s files, folders, and URLs.

This is the best way to avoid letter-case issues impacting your website performance and search engine optimization initiatives.

URL Capitalization: Does It Matter For SEO?

Yes, a website with numerous URL capitalization discrepancies can face indexing issues. Even though this doesn’t directly affect search engines, your indexing will suffer.

A neat and consistent website can improve crawlability and indexability. So, why just not make it easy for search engines?

That’s exactly what we do at Atropos Digital.

We analyze and plan, methodically streamlining your entire website with the latest search engine trends and SEO principles.

Plus, we thoughtfully incorporate topics and answers your audience is looking for.

The result? Increased visibility for search engines and prospects alike!

So, if you are ready to take your website to the next level, contact us for a strategy call.