Can servers block curl requests?

Question

I am working on ZOHO API and trying to update the record using cURL. I tried different cURL variations, but it always returns \"false\". But when I call the same URL using a

Answer 1

Servers cannot block cURL requests per se, but they can block any request that they do not like. If the server checks for some parameters that your cURL request does not satisfy, it could decide to respond differently.

In the vast majority of cases, this difference in behavior is triggered by the presence (or absence) and values of the HTTP request headers. For example, the server might check that the User-Agent header is present and has a valid value (it could also check lots of other things).

To find out what the HTTP request coming from the browser looks like, use an HTTP debugging proxy like Fiddler or your browser's developer tools.

To add your own headers to your cURL request, use

curl_setopt($ch, CURLOPT_HTTPHEADER, array('HeaderName: HeaderValue'));