Choosing the IRS environment

The IRS Environment toggle in the header controls which IRS environment you authenticate and transmit to.

Test: The IRS Assurance Testing System (ATS) environment. Use this for testing. Test is the default environment.
Production: The live IRS production environment. Use this only for real 1099 filings.
Note: Switching the environment ends your current authenticated session. After you switch, you must authenticate again before you can transmit or check status. The status bar confirms the change with a message such as "IRS environment set to Production. Re-authentication required."

The toggle is locked (disabled) while a transmission batch is running, while a single file is being sent, and while a status check is in progress, because changing the environment during those operations would interrupt them.