By sending HTTP requests to Salesforce endpoints, you can create, manipulate, and search data using REST API tools. Depending on where you send requests, you access and operate on different pieces of information, called resources. Resources include records, query results, metadata, and more.
There are a number of web interfaces you can use to access your Salesforce data without having to access the Salesforce user interface. With API access, you can perform operations and integrate Salesforce into your applications as you like.