> ## Documentation Index
> Fetch the complete documentation index at: https://docs.mainwp.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Does MainWP have Visual Regression Tests?

> The Regression Testing add-on monitors Child Site source code changes after plugin, theme, or core updates. Compare HTML snapshots, review CSS/JS changes, and receive email notifications when changes exceed thresholds.

MainWP offers the **[Regression Testing](https://mainwp.com/add-on/regression-testing/)** add-on to detect visual and code changes on your child sites after updates.

## What You'll Learn

* What the Regression Testing add-on does
* Key features available
* How to get started

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## What It Does

The Regression Testing add-on monitors changes in your child sites' source code. It helps you spot unexpected modifications after plugin, theme, or WordPress core updates by comparing HTML snapshots between scans.

<img src="https://mintcdn.com/mainwp/ZezLcvKnTQaPggvh/images/faq/visual-regression-before.jpg?fit=max&auto=format&n=ZezLcvKnTQaPggvh&q=85&s=bb6ceedb9c7795cbdda80851e49bdc31" alt="Regression Testing add-on overview showing monitoring features" width="1024" height="504" data-path="images/faq/visual-regression-before.jpg" />

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## Key Features

| Feature             | Description                                           |
| ------------------- | ----------------------------------------------------- |
| HTML snapshots      | Compare page source before and after updates          |
| Change threshold    | Set acceptable change percentage before notifications |
| Email alerts        | Receive notifications when changes exceed thresholds  |
| Flexible scheduling | Daily, weekly, twice monthly, or monthly scans        |
| Auto-trigger        | Run scans automatically after updates                 |
| CSS/JS tracking     | Monitor changes to stylesheets and scripts            |
| Custom pages        | Monitor any page, not just the homepage               |

***

## Comparison Views

The add-on provides multiple ways to review differences:

* Raw HTML comparisons
* Rendered before/after views
* CSS/JS file changes (when tracking enabled)

<img src="https://mintcdn.com/mainwp/ZezLcvKnTQaPggvh/images/faq/visual-regression-after.jpg?fit=max&auto=format&n=ZezLcvKnTQaPggvh&q=85&s=539758c2b26b2e485b53d8056ceb5520" alt="Regression Testing comparison view showing HTML differences between scans" width="1024" height="504" data-path="images/faq/visual-regression-after.jpg" />

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## Get Started

For complete setup instructions and configuration options, see the [Regression Testing documentation](/add-ons/security/regression-testing-extension).

***

## Related Resources

* [Regression Testing Add-on](https://mainwp.com/add-on/regression-testing/) - Product page
* [Manage Updates](/sites/updates/manage-updates) - Update management in MainWP
* [Does MainWP Have Safe Updates](/sites/updates/does-mainwp-have-safe-updates) - Update safety features