Sandbox
The Sandbox is a free environment for application development and testing with mock data. It supports all Plaid functionality, including the Plaid API and Plaid Link. The Sandbox provides a variety of test accounts and institutions to test against, and developers can create an unlimited number of test Items.
The Sandbox is designed for development purposes and does not interact with any real data, which is ideal for developers who are experimenting with Plaid or still working out the bugs in their application.
Production
Use the Production environment to deploy an application with Plaid’s products or to test with live data. This environment provides access to real data.
Approval for the Production environment takes a couple of business days, and you'll need to provide more information about their company and how you plan to use the Plaid API. The Plaid dashboard walks you through the process of requesting production access.
Limited Production
Limited Production is a special mode of the Production environment that is available for some Plaid products and can be used to try the Plaid API with real data before obtaining full Production access. In Limited Production, you have access to Plaid's Production server and can make a limited number of free API calls, but your API usage is capped and some functionality is unavailable. Unlike Sandbox, Limited Production is not a separate environment from Production. For more details on Limited Production, see Testing with Real Data in Limited Production.