To integrate Salesforce and other system, you need to make sure they may communicate with each other.
Web-to-lead is an example for Salesforce to capture message from others. Another example is a variant of “Get data through Salesforce REST API” section in my last post. You may change the Salesforce Object Query Language (SOQL) in Apex code into Salesforce Object Search Language (SOSL) for more flexible database operation in Salesforce.
Another case is when Salesforce need to pass data to other service. This is our focus. Here I am going to how to capture Salesforce Outbound Message with PHP.