For example:

1. If you use residential rotating proxies and a site blocks you with some specific test, you might want to retry the request instead of getting the successful screenshot of the page with the CAPTCHA or an error.
2. Setting fail_if_content_missing=<some string that present in the working page content> for your screenshot requests allows you to automatically ignore captures showing “Coming Soon” on a product page, ensuring you only get notified when the page updates to show the product is available for purchase.
3. To focus monitoring on actual uptime and avoid capturing screenshots during nightly maintenance, configure your requests with fail_if_content_missing=<some string that present in the working page content>, thereby skipping any maintenance messages displayed on your application’s homepage.

That’s exactly what you need the option fail_if_content_missing for.

Let’s quickly see how it works and how you can use it. Let’s first render the example.com page:

https://api.screenshotone.com/take?url=https://example.com&fail_if_content_missing=example+domain&access_key=<your access key>

The result is:

As you might notice, the match is case insensitive, it is done for simplicity.

Now, let’s try to fail it:

https://api.screenshotone.com/take?fail_if_content_missing=some+random+string+to+fail&url=https://example.com&access_key=<your access key></your>

The result is:

{
    "is_successful": false,
    "error_message": "The page content is missing the requested string `some random string to fail` by the `fail_if_content_missing` option. If it seems to be a mistake or not what you expected, please, reach out to `support@screenshotone.com` as quickly as possible, and will assist and try to resolve your problem.",
    "error_code": "content_missing_requested_string"
}

It works!

Also check out the fail_if_content_contains option.