How to Monitor Website Changes Automatically in 2026
Why monitor websites?
The internet changes constantly. Prices drop, job listings appear, competitors update their pages, legal terms shift — and most of it happens without anyone noticing.
If you've ever:
- Missed a price drop on something you wanted to buy
- Found out about a job posting after it was already filled
- Discovered a competitor launched a new feature weeks ago
- Had a client's website go down without anyone catching it
…then you already know the pain of manually checking websites.
The good news: you don't have to do it manually anymore.
Manual checking vs automatic monitoring
Manual checking means opening a browser, visiting a URL, and scanning the page for changes. This works for one or two sites. It breaks down completely when you're tracking five, ten, or fifty pages.
Automatic monitoring uses a tool that periodically fetches a webpage, compares it to the previous version, and alerts you when something changes. The key advantages:
- You never forget to check. The tool runs on a schedule whether you remember or not.
- You see exactly what changed. Good tools show you a visual diff — additions in green, removals in red — so you don't have to hunt for the difference.
- You get notified instantly. Push notifications, email, or even AI-powered alerts mean you react faster.
How to set up automatic website monitoring with Site Spy
Site Spy is a free browser extension that monitors websites and shows you visual diffs of exactly what changed. Here's how to get started in under 60 seconds.
Step 1: Install the extension
Install Site Spy from the Chrome Web Store or Firefox Add-ons. It's free — no account required for basic monitoring.
Step 2: Add a URL to watch
Click the Site Spy icon in your browser toolbar. You'll see the popup with your watch list (empty at first). Paste any URL and click Add Watch.
Alternatively, you can right-click on any page and select "Watch this page" from the context menu.
Step 3: Pick specific elements (optional)
This is where Site Spy really shines. Instead of monitoring the entire page (which triggers on every ad rotation or cookie banner change), you can click on a specific element — like a price, a headline, or a status badge.
Open any page, click the Site Spy icon, and choose "Pick Element". A visual overlay lets you click on exactly the part of the page you care about. Site Spy generates a stable CSS selector and only monitors that element.
Step 4: Set your check interval
Choose how often Site Spy should check for changes:
- Free plan: Every hour (great for most use cases)
- Starter plan (€4/mo): Down to every 10 minutes
- Pro plan (€8/mo): Down to every minute
For price tracking, hourly is usually fine. For job boards or time-sensitive pages, consider faster intervals.
Step 5: Get notified when something changes
When Site Spy detects a change, you'll get:
- A browser push notification (free)
- An email notification (Starter and Pro plans)
- A badge count on the extension icon showing unread changes
Click the notification to open the visual diff viewer, where you can see exactly what was added, removed, or modified — highlighted in green and red.
Common use cases
Track price drops
Monitor product pages on Amazon, Best Buy, or any e-commerce site. Use the element picker to select just the price element so you don't get false alerts from changing reviews or "customers also bought" sections.
Watch job boards
Add career pages from companies you're interested in. Site Spy will notify you the moment a new listing appears — often hours before job aggregators pick it up.
Monitor competitors
Track competitor landing pages, pricing pages, and feature lists. When they change their positioning or launch something new, you'll know immediately.
Follow government and legal pages
Regulations, permit statuses, court filings — many of these are published on websites that update without any announcement. Site Spy catches those updates automatically.
Keep tabs on content
Blogs, news sites, forums, release notes — any page that updates irregularly. Instead of checking manually, let Site Spy watch it for you.
How Site Spy compares to alternatives
| Feature | Site Spy | Visualping | Distill.io |
|---|---|---|---|
| Free plan | 5 URLs, hourly | 5 URLs, daily | 25 URLs (local only) |
| Element picking | Visual click-to-select | Screenshot regions | CSS selectors (manual) |
| Visual diffs | Side-by-side + unified | Screenshot overlay | Text only |
| Browser extension | Chrome + Firefox | Chrome only | Chrome + Firefox |
| Web dashboard | Yes | Yes | No (paid feature) |
| AI integration (MCP) | Yes | No | No |
| Starting price | €4/mo | €10/mo | €8/mo |
Tips for effective monitoring
- Use element picking instead of full-page monitoring. This eliminates false positives from ads, dynamic content, and cookie banners.
- Start with hourly checks. Most websites don't change every minute. Hourly catches 99% of meaningful changes.
- Organize with tags. Group your watches by category (shopping, jobs, competitors) to keep your dashboard clean.
- Check the diff viewer. Don't just rely on notifications — the visual diff often reveals context around the change that's just as useful.
Get started
Site Spy is free for up to 5 watched URLs with hourly checks. No credit card required.
Install for Chrome · Install for Firefox · Open the Web Dashboard