Fixing PHP cURL SSL Error: Self Signed Certificate in Certificate Chain

When using PHP cURL to make HTTPS requests, you may encounter the error "SSL certificate problem: self signed certificate in certificate chain". This issue occurs because the client root certificate cannot be verified. Below are the solutions.

Method 1

Ignore certificate verification by adding the following code to your cURL method:

curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);

Disadvantage: You must add the above code to every cURL method, which can be cumbersome.

Method 2

Download the root certificate from the cURL official website: cacert.pem, then modify php.ini to include this certificate and restart your web server.

# Add to php.ini
[SSL]
curl.cainfo = "D:\xampp\php\cacert.pem"
openssl.cafile = "${curl.cainfo}"

Parts of this article reference: [PHP] PHP cURL https SSL certificate problem: unable to get local issuer certificate