* Bulk API is a RESTful API that allows you to load or delete large sets of data in Salesforce. It does not bypass the storage limits of your environment, but it can handle more records and run faster than other APIs12. Bulk API is useful for development, testing, and integration scenarios.
* Developer and Developer Pro sandboxes are two types of sandboxes that you can use to create and test applications in Salesforce. They have different storage limits and refresh intervals. Developer sandboxes have a 200 MB data storage limit and can be refreshed once per day. Developer Pro sandboxes have a 1 GB data storage limit and can be refreshed once every 5 days3 .
* Data import wizard is a web-based tool that you can use to import or update up to 50,000 records in Salesforce. It is not a client application, but a feature that is available in the Setup menu of Salesforce .
References:
* 1: Bulk API Developer Guide
* 2: Cert Prep: Platform Developer I: Data Modeling and Management
* 3: Sandbox Types and Templates
* : Cert Prep: Platform Developer I: Testing and Debugging
* : [What Is the Data Import Wizard?]
* : Cert Prep: Platform Developer I: Business Logic and Process Automation