...
XML
Standards based
WSDL (a package to define all the methods) needs to be downloaded and saved to the server
System to system
State maintained
Built in security
OAuth or Session ID (OLD)
Can build Custom SOAP Web Services
Standard Salesforce WSDL
SOA (Service Oriented Architecture) Callout (eg bring data into external systems)
Synchronous
Web Service API
Anything referring to Web Service relates to SOAP.
Custom Web Service is inbound
Enterprise WSDL
Strongly Typed
For a specific org - has all of the customisations in that org
Changes if the org changes (eg custom fields added)
...
Loosely typed
Can be used against any org (eg used by partners)
Static - only changes based on API version?
REST
“lower level on the networking stack” (dunno if it’s important, but it was repeated many times in a 2011 video)
XML or JSON
REST has in-built discovery of the available methods / endpoints
Lightweight
Security usually via OAuth
Old via Session ID
Standard Salesforce endpoints on every object (Standard and Custom)
Web service implementations
Expose your own APEX classes as REST Endpoints
GET POST DELETE PATCH PUSH
Bulk API uses REST See https://tddprojects.atlassian.net/wiki/pages/createpage.action?spaceKey=SF&title=Salesforce%20APIs&linkCreation=true&fromPageId=1310556166
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One way SSL is enabled by default.
Two way SSL needs self-signed or CA-signed certificates
TLS
Transport Layer Security
You upload your certificate to Salesforce
You can download salesforce client certificate to authenticate on your web server.