Data Loader is a tool that allows administrators to import or export large amounts of data (more than 50,000 records) from or to Salesforce using CSV files. Data Loader can be used for inserting, updating, deleting, upserting, exporting, or extracting data. Bulk API is an API that allows administrators to process large batches of records asynchronously in the background. Bulk API can handle millions of records with high performance and minimal system resources. By using Data Loader with Bulk API enabled, an administrator can import a large amount of historical data (more than 100,000 records) from another system efficiently and securely. References: https://help.salesforce.com/s/articleView?id=sf.data_loader.htm &type=5 https://help.salesforce.com/s/articleView?id=sf.loader_api.htm &type=5 https://help.salesforce.com/s/articleView?id=sf.bulk_api_intro.htm &type=5