If you want to check if a URL exists while using the REST API task, you can use this example:
There are scenarios where the success of a URL is critical. If a URL fails, you may want your SSIS process to stop. Here’s an example of how to set up a REST API Task to handle errors, save the result in a variable, and use the Validator Task to mark a URL as invalid in case of failure.
Now for the validator task use the output from the REST API’s variable and use the expression false. If the variable’s value is false, then the URL is not valid
The last step is running the package. Here you will see the two cases