Running Apex

You can access many features of the Salesforce user interface programmatically in Apex, and you can integrate with external SOAP and REST Web services. You can run Apex code using a variety of mechanisms. Apex code runs in atomic transactions.

Invoking Apex
You can run Apex code with triggers, or asynchronously, or as SOAP or REST web services.
Apex Transactions and Governor Limits
Apex Transactions ensure the integrity of data. Apex code runs as part of atomic transactions. Governor execution limits ensure the efficient use of resources on the Lightning Platform multitenant platform.
Using Salesforce Features with Apex
Many features of the Salesforce user interface are exposed in Apex so that you can access them programmatically in the Lightning Platform. For example, you can write Apex code to post to a Chatter feed, or use the approval methods to submit and approve process requests.
Integration and Apex Utilities
Apex allows you to integrate with external SOAP and REST Web services using callouts. You can use utilities for JSON, XML, data security, and encoding. A general-purpose utility for regular expressions with text strings is also provided.