How to monitor content changes on any website and get alerts

Step-by-step guide to setting up a content watcher to monitor changes. Automatically get email or Slack alerts when content changes on any website.

Content

Some websites, typically in the area of e-commerce, provide a feature called a watchdog that you can use to get a notification when something changes (usually a product price). This feature is really handy –  you don’t need to remember to regularly open the same page to see if something changed. Our Content Checker lets you set up such a watchdog for any website and get an email notification whenever the content you want to monitor changes.

Just think about how often you’ve checked the same page every evening to see if tickets are already available or on sale, a product price is below what you want to pay, your competitor changed their homepage, or there’s a new version of a library your work depends on. This is the issue that Content Checker was created to solve, and we’ll show you how to set up this watchdog to keep you in the loop before everyone else.

Applications of a watchdog program

Content Checker is one of the most popular Actors on the Apify platform. The reason for this is simple: it allows you to monitor specific content on any web page and sends a notification with before and after screenshots whenever that content changes. This allows automated monitoring of anything from prices to availability which can be useful both for business and personal use.

This makes Content Checker a truly universal solution because you can use it to:

Basically, Content Checker enables you to automate tracking changes in any content that you want to keep an eye on. It can be literally any parameter that gets updated – that’s the best part of the idea behind web automation and, in part, web scraping. You don’t have to spend time doing things manually if you can get a bot to do it!

How Content Checker works

The logic behind the website checker is simple as well: it searches for specific text in a chosen CSS selector and compares the current results to the original state. If there is any change, Content Checker launches another Actor to send an email or a Slack notification and also makes and sends screenshots before and after the change occurred on the website. Let's find out how to use it...

Step-by-step guide on how to set up your own website watcher program

No time for reading today? Video guide to the rescue:

Content Checker video tutorial

1. Go to Content Checker on Apify Store

First, we need to go to Content Checker on Apify Store. Click the Try for free button to get started. If you don't already have an Apify account, you'll be prompted to sign up for a free account first.

1. Go to Content Checker on Apify Store
You can try Content Checker for free on Apify Store

If you already have an account, you'll be taken straight to Apify Console, where you can configure the tool.

The Content Checker Actor in Apify Console

If you don't already have an Apify account, you'll be prompted to sign up for a free account first.

Sign up for a free Apify account

2. Provide the URL you want to monitor

We're going to replace the default input URL with a mock website URL created for this demo.

Mock website

You can just copy the URL and paste it into the URL to check field.

2. Provide the URL you want to monitor
Insert the website URL in the input field

3. Select the area you want to monitor

In this example, we want to monitor any price changes on this website. Go to the web page you want to monitor and click Inspect to open Developer Tools and find the CSS selector for price.

Select Inspect in the developer tools
Select Inspect in the developer tools
3. Select the area you want to monitor
CSS selector for price

Now paste it into the Monitored area selector field. Don't forget to put a period (.) in front.

Paste the CSS selector in the input field (add a period in front)
Paste the CSS selector in the input field (add a period in front)

4. Select the area you want to screenshot

Go back to the developer tools to select the area you want to screenshot. In our case, we want to take a screenshot of the entire product view.

4. Select the area you want to screenshot
Select the area you want to screenshot

Select the CSS selector and paste it into the Screenshot selector field. Again, don't forget to put a period (.) in front.

Paste the CSS selector into the screenshot selector field (add a period in front)
Paste the CSS selector into the screenshot selector field (add a period in front)

5. Choose an email address for receiving notifications

Insert the email address for notifications in the Email address field. You can also adjust the text in the Notification Text field. The default is Apify found a new change!

5. Choose an email address for receiving notifications
Choose an email address to receive notifications and choose a notification text

6. Save your configuration as a new task

Click Save as new task at the bottom of the screen. This will save your configuration so you can re-use it later. Now that your task is created click the Start button to run it.

6. Save your configuration as a new task
After saving your configuration, click Start, and the run will begin. The status will change to Succeeded when a successful run has finished.

Once the run has finished, the status will change to Succeeded, and you can see the results in the Output tab. As this was the first run, there's no data to compare and so no email will be sent to us. Now we need to set up Content Checker to run on a schedule so we can regularly check the website and monitor any price changes.

7. Schedule the Actor

To schedule Content Checker to run automatically:

a. Go to saved tasks and select the task you want to schedule.

Scheduling a. saved task
Choose the saved task you want to schedule

b. Go to Actions and select Schedule.

Go to Actions and select schedule in the dropdown
You can find and adjust your scheduled tasks by clicking the Schedules tab in the left sidebar

c. Choose the frequency of the run (in our case, we'll choose Hourly), then click Create.

7. Schedule the Actor
Choose how often you want Content Checker to run

Now your schedule is set up. You can find and adjust your scheduled tasks by going to the Schedules tab in the left sidebar.

Once Content Checker detects a change on the page, you'll receive an email with before and after screenshots.

Email notification for a website change
Email notification for a website change
Before and after screenshots for a price change
Before and after screenshots for a price change

And that’s everything you need to know to get started using Content Checker.

If you prefer getting Slack notifications rather than emails, check out our video tutorial on integrating Apify Actors with Slack.

Natasha Lekh
Natasha Lekh
Crafting content that charms both readers and Google’s algorithms: readmes, blogs, and SEO secrets.

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