WebChange Detector for MainWP adds a visual safety net to the updates you already run from your MainWP Dashboard. Before the updates, it captures screenshots of the pages you selected on every child site. It then installs the updates and captures the same pages again. The screenshots are compared au
PricingFree downloadThe WordPress.org download is free. Pro versions, add-ons or external services may cost extra.
CompatibilityRequires WordPress 6.0 and PHP 7.4.
SourceWordPress plugins · Nov 1, 2026
01 / Source details
Aboutthistool.
WebChange Detector for MainWP adds a visual safety net to the updates you already run from your MainWP Dashboard. Before the updates, it captures screenshots of the pages you selected on every child site. It then installs the updates and captures the same pages again. The screenshots are compared automatically, and you instantly see which pages changed, with the visual difference highlighted.
Everything runs from your MainWP Dashboard. Nothing is installed on your child sites.
What is an on-demand check?
An on-demand check is a visual diff you run around a change you make yourself, like installing updates. WebChange Detector takes a screenshot of each selected page before the change, applies the change, takes another screenshot after , and compares the two automatically. The comparison runs on desktop and mobile, and the AI ignores moving parts like sliders, carousels, ads and animations, so you only get flagged on changes that actually matter. In MainWP, this on-demand check is wrapped directly around the updates you run from your dashboard: pre-update screenshots, the updates, post-update screenshots, and the comparison all happen in one run across all your child sites.
How it works
01Create a free WebChange Detector account at webchangedetector.com if you do not have one yet, then copy your API token from your account and enter it in MainWP.
02Enable the child sites you want to check.
03Sync each enabled child site’s pages with “Sync WP URLs” so its pages become available, then select the pages to check (desktop and/or mobile).
04Click “Run visual checks & updates” on your MainWP dashboard or Updates page.
05The plugin captures pre-update screenshots, installs all pending updates, captures post-update screenshots and compares them. Before the pre-update screenshots and after the updates, the cache on each child site is cleared automatically, so the screenshots always show the real, freshly generated state of the site.
06Review the results on the Checks tab: every page with a visual change is flagged, including an AI summary of what changed.
Features
One-click WCD Updates: pre-update screenshots, updates, post-update screenshots, comparison: all in one run across all child sites.
Start a run where you already work: “Update Selected with Checks” and “Update All with Checks” on MainWP’s own Updates page (WordPress, Plugins, Themes and Translations) with MainWP’s row selection, on each child site’s Updates subpage, from the WCD Updates widget on your Operations dashboard and every site overview, or for the whole fleet from the Run tab.
Automatic cache clearing: the child site’s cache is cleared before the pre-update screenshots and after the updates, so screenshots never show a stale cached page. Works with 20+ caching plugins (WP Rocket, LiteSpeed Cache, W3 Total Cache, WP Super Cache and more) through the MainWP Child plugin, with nothing extra to install.
Page selection per site: choose which URLs are checked, separately for desktop and mobile.
Check settings per site: screenshot region, difference threshold, alert emails, which devices new URLs are activated for, Basic Auth, static IP proxy, screenshot delay, and CSS or JS injection.
Checks overview: all runs across your sites with filters, change percentages and side-by-side comparisons.
Live run popup: a Pre-update, Updates, Post-update and Done timeline with per-site progress, and automatic resume if you navigate away mid-run.
Your account in the dashboard: sign up on the Account tab or connect an existing account with your API token, and see your plan, remaining checks and active sites.
Auto-enable new sites: optionally provision every newly added MainWP child site for visual checks automatically.
External service: WebChange Detector
This plugin relies on the WebChange Detector service ( https://www.webchangedetector.com ) as a third-party service to capture, store and compare the screenshots. A WebChange Detector account is required (free plan available).
The plugin sends data to api.webchangedetector.com only after you have entered your API token or submitted the account signup form, and only in these circumstances: when you create your free trial account from the Account tab (your first and last name, email address, a hashed version of your chosen password (never the plain text password), your dashboard site’s domain and server IP address are transmitted to create the account), when you connect or verify your account, when you enable a child site or sync its page URLs (the public URLs and page titles of that site are transmitted), when you start a visual check (screenshots are taken of the selected public URLs), and when you review or update results. Your API token is sent with each request to authenticate your account. No data about your WordPress users or any non-selected content is transmitted.
Service: https://www.webchangedetector.com
Terms of use: https://www.webchangedetector.com/terms-of-use/
A MainWP Dashboard (the free MainWP plugin ) with at least one connected child site.
A WebChange Detector account and API token. If you do not have an account yet, create a free one at webchangedetector.com ; the free plan includes monthly checks. See plans for paid options.
See it in action
Screenshots & previews.
The WCD Updates widget on your MainWP Operations dashboard: how many sites have updates, how many pages and checks the next run will cover, and one button to start it.Pre-flight summary before the run: sites, pages, checks and credit coverage, plus the exact updates that will be installed, per site.The live run popup: a Pre-update, Updates, Post-update and Done timeline with per-site progress. When it finishes you see "All good" or the number of pages to review, with Re-check and View results.Side-by-side before/after comparison with the AI change analysis: real changes flagged, dynamic content auto-ignored, with the visual difference percentage and a browser-console check.The Run tab on the WebChange Detector extension page: start a WCD Updates run across all your enabled sites.The Checks tab: every run across your sites with filters for date, status, website and detection, plus an AI summary per run.The Settings tab: activate a website and choose which URLs are checked, separately for desktop and mobile. One click activates checks for all your managed websites.The Account tab: your plan, remaining checks and active sites, the API token, auto-enable for new sites, and the reset-connection option.
02 / Source details
Gettingstarted.
01Install and activate the plugin on the WordPress site running your MainWP Dashboard (not on the child sites).
02Create a free WebChange Detector account at www.webchangedetector.com if you do not have one yet.
03Copy your API token from your WebChange Detector account.
04Go to MainWP > Extensions > WebChange Detector and paste the API token into the “WebChange Detector API Token” field.
05Enable the child sites you want to check.
06Sync each enabled child site’s pages with “Sync WP URLs” so its pages become available.
07Select the pages to check for desktop and/or mobile.
08Run your next update from the MainWP dashboard with “Run visual checks & updates”.
03 / Source details
Frequently asked questions.
What is an on-demand check?
An on-demand check is a visual diff you run around a change you make yourself. WebChange Detector takes a screenshot of each selected page before the change, you apply the change, it takes another screenshot after, and the two are compared automatically on desktop and mobile. In MainWP this is wrapped around the updates you run: the plugin captures the pre-update screenshots, installs the updates, captures the post-update screenshots, and shows you every page that changed, with an AI summary. The AI ignores moving parts like sliders, carousels and ads, so you only get flagged on real changes.
Do I need to install anything on my child sites?
No. The plugin runs entirely on your MainWP Dashboard and talks to the WebChange Detector service. Child sites are captured through their public URLs.
Do I need a WebChange Detector account?
Yes. The screenshots are captured and compared by the WebChange Detector service, so you need an account and API token. A free plan is available.
Which pages are checked?
You choose. After enabling a child site, its published pages and posts are synced and you select which URLs are checked, separately for desktop and mobile. Every selected URL and device counts as one check per capture.
Why do I need to sync the child site’s pages?
Before it can check a site, the plugin needs the list of public URLs on that site. Syncing fetches the published pages and posts from the child and makes them available for selection. It runs automatically when you enable a site and again after MainWP syncs the child. Until a site is synced, there are no pages to select and no checks can run.
What happens if a site is offline during an update run?
The run tolerates it: the offline site is skipped for updates and the other sites continue. The post-update screenshots still run for the sites that were updated.
Do I need to clear the cache on my child sites after updates?
No, the plugin does that for you. It clears each child site’s cache before the pre-update screenshots and again after the updates, using the cache clearing built into the MainWP Child plugin (supports 20+ caching plugins, detected automatically). This makes sure the comparison shows the actual state of the site after the updates instead of a cached old version. If no supported caching plugin is active, this step is simply skipped.
Does this work with MainWP updates started elsewhere (e.g. scheduled)?
No. Only updates you start with one of the plugin’s own “with Checks” buttons are checked. Updates started with MainWP’s own update buttons, and scheduled or automatic updates, run without any screenshots or comparisons, so they never use check credits.
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