HTTP is a protocol(rules) used in web-based communications. There exist various types of HTTP methods, Some of them are:
- Get: To get the data through the API
- Post: To post the data through the API
- Put: To put the data through the API
- Delete: To delete the data through the API
Out of all of the HTTP methods, GET and POST methods are majorly used as nowadays APIs come up with lots of customization.
Introduction To API Callout
API callout means sending a request to the external system to get some data or to send some data like calling an API of google sheets to get data from Google Sheets. API callout in salesforce is done in apex language.