Understanding Regex In Google Analytics 4 (GA4)

If you’ve ever tried to filter data in Google Analytics 4 (GA4) and come across the term "regex", you might have wondered what it is and how it works. 

Regex (short for Regular Expressions) is a tool that helps you search for and match specific patterns in text.

In GA4, regex is used to filter reports, define segments , exclude traffic , and create more accurate data insights. 

Instead of manually listing multiple conditions, regex allows you to write a single expression that captures all relevant data points efficiently.

This post will help you understand regex in GA4 in simple terms, with clear examples to help you apply it with confidence.

👉 Next Content: Check out our post, "How to Use Regex in GA4" for a detailed explanation, step-by-step guide, and screenshots. It’s the next step to applying what you’ve learned about regex in GA4.

Basic Regex In GA4

Understanding basic regex can help you filter data more precisely, like viewing only blog page traffic. It allows you to exclude unnecessary traffic, such as internal company visits.

You can also create dynamic audience segments, like users who visited product pages, and improve event tracking by grouping similar URLs.

In this section, we'll explain basic regex in GA4 with real-world examples.

Real-World Examples of Basic Regex in GA4

Let’s say you run an online store, and your product pages follow this URL structure:

• yourstore.com/products/12345
• yourstore.com/products/67890
• yourstore.com/products/11223

If you want to see only product page visits in GA4, you can’t just use a basic “contains” filter for /products/, because it might also include /products-list/ or /products-on-sale/.

With regex, you can write:

.*/products/\d+$

This means:

•   .* → Matches anything before /products/
•   /products/ → Ensures we only capture product pages
•   \d+ → Matches any numbers (product IDs)
•   $ → Ensures the URL ends there (avoids capturing additional text)

What is Regex In Google Analytics 4 (GA4)?

Regex, as an abbreviation of “Regular Expressions” is a special way of searching for patterns in text. 

Instead of looking for exact words or numbers, regex allows you to define rules that match different variations of text.

Think of regex like a smart search tool. Instead of manually listing every possible match, you can create one rule that captures all the data you need.

For example, if you want to find all URLs that start with /blog/, you could write:

^/blog/ 

This tells GA4:

•  ^ → Match only if the text starts with /blog/
•  /blog/ → The part you are searching for

How Does Google Analytics 4 (GA4) Use Regex?

In Google Analytics 4, regex is mainly used to filter, segment, and group data more efficiently. Here are some ways you might use it:

• Filtering reports → Show only specific types of pages (e.g., product pages, blog posts).
• Creating audience segments → Group users based on their browsing behavior.
• Excluding unwanted traffic → Block internal traffic or spam referrals.
• Setting up custom channel groups → Categorize traffic sources dynamically.

Regex vs. Normal Filters in Google Analytics 4 (GA4)

Example: Why Use Regex Instead of Basic Filters?

Imagine you want to track visits to your product pages, and they follow different URL structures:

• /products/12345
• /shop/product/67890
• /store/items/11223

A basic GA4 filter would require you to enter multiple conditions. But with regex, one rule can match them all:

.*(products|shop/product|store/items)/\d+$ 

Now, any page that fits this pattern will be included without needing multiple conditions.

Why Use Regex in Google Analytics 4 (GA4)?

Google Analytics 4 (GA4) provides different ways to filter and analyze data, but regex is the most flexible and efficient method.

Instead of manually entering multiple conditions, regex allows you to define one concise rule that captures everything you need.

Using Regex For Filtering Data More Precisely

Example: You want to track only users visiting your blog pages.

• Without regex, you would need to enter multiple filters such as:
• • /blog/
  • /news/
  • /articles/
• With regex, a single rule covers all cases:

.*/(blog|news|articles)/.*

This ensures GA4 captures any page containing these words in its URL.

Using Regex For Excluding Unwanted Traffic

If you want to prevent internal company visits from affecting your GA4 reports, you can exclude internal IP addresses using regex.

• Instead of entering every IP manually, such as 192.168.1.1, 192.168.1.2, and so on,

Use a regex rule to cover a range of addresses:

192\.168\.1\.\d+

Using Regex For Creating Dynamic Audiences

GA4 allows you to group users into segments and audiences. Regex helps define these groups more efficiently.

• Example: You want to create an audience for users who visited any product page, such as /products/item123 or /shop/item987.
• Regex rule:

.*/(products|shop)/item\d+$

This matches any URL containing /products/ or /shop/ followed by an item number.

Using Regex For Customizing Traffic Source Grouping

Regex allows you to categorize multiple traffic sources under a single group.

• Example: You want to track social media traffic from Facebook, Instagram, and LinkedIn.
• Instead of manually entering each source, use regex:

(?i)(facebook|instagram|linkedin)

• (?i) makes it case-insensitive, so it matches both "Facebook" and "facebook".
• | acts as an OR operator, allowing it to match any of the listed platforms.

Regex vs. Manual Filters: Which is Better?

Here is a quick comparison table of regex filters vs. manuel filters in Google Analytics 4 (GA4):

Understanding Basic Regex Syntax In Google Analytics 4 (GA4)

To use regex in GA4 effectively, it is important to understand its basic syntax. 

Regex consists of special characters and rules that help define search patterns. 

Below is a beginner-friendly explanation of these key elements, along with examples of how they work.

Google's Approach to Regex: The RE2 Engine

Many tools and programming languages, such as Python and Java, use different versions of regex with their own rules.

However, Google keeps things consistent by using the RE2 Regex engine across most of its products, including Google Analytics 4 (GA4), Looker Studio , and BigQuery.

This means that once you learn how regex works in GA4, you can apply the same knowledge in other Google tools without needing to adjust for different formats.

To make sure your regex patterns work correctly in GA4, you can test them using Regex101. Simply select the "RE2 (Google)" option when testing your expressions.

This helps you refine your patterns and avoid errors before applying them to reports or data filters.

Wildcards: Matching Any Character or Repetition

Wildcards allow flexibility when searching for patterns in text.

Anchors: Specifying Start or End of Text

Anchors define where a match should begin or end.

Escape Characters: Using Special Characters as Normal Text

Some characters in regex have special meanings, such as . or ?. To use them as normal text , add a backslash (\) before them.

Groups and Ranges: Matching Specific Character Sets

Groups help organize parts of a regex pattern, while ranges allow matching multiple characters.

Repetition: Controlling the Number of Matches

Curly brackets { } help define how many times a pattern should appear.

Conclusion: Guide To Regex In Google Analytics 4 (GA4)

Regex in GA4 helps you filter, segment, and analyze data more efficiently by defining patterns instead of using multiple filters. 

Understanding basic syntax like wildcards, anchors, and groups allows for more precise data control. 

Since GA4 uses Google’s RE2 regex engine, the same skills apply to other tools like Looker Studio and BigQuery.