Sonar allows you to integrate with Fannie Mae’s Desktop Originator (DO) or Desktop Underwriter (DU) and Freddie Mac’s Loan Product Advisor (LPA) to run automated underwriting directly within your workflow.
Before running AUS inside Sonar, you will need to enter your credentials inside Sonar.
You can set up these connections at either the Company level (shared across your team) or at the User level (for your individual use only).
Set Up and Activate an AUS Integration
Follow these steps to connect to Fannie Mae or Freddie Mac:
Go to Settings > Integrations
Click Add Integration
Select Integration Type:
AUS – Fannie Mae (DO) or Fannie Mae(DU)AUS – Freddie Mac (LPA)
Enter the required credentials (see below)
Click Test to verify the connection
Click Save
Use the Active Integration toggle to make the AUS connection active
Required Credentials by AUS Provider
Fannie Mae (DO or DU)
Field | Description |
Username | DO/DU account username the user name should be entirely lower case |
Password | DO/DU account password |
Not sure which to use?
DO (Desktop Originator) – For mortgage brokers sponsored by a Fannie Mae Seller/Servicer
DU (Desktop Underwriter) – For lenders who are Fannie Mae-approved Seller/Servicers
Freddie Mac (LPA)
Field | Description |
S2S Username | Your system-to-system username (usually includes |
S2S Password | System-to-system password |
Party Type | Your LPA Role (e.g., Mortgage Broker) |
Party Number | TPO Number or Seller/Servicer Number
This will be 7 digits for a mortgage broker or correspondent lender. If you are a seller, this will be 6 digits |
Note: You must provide System-to-system (S2S) credentials, not your credentials. Your S2S username will contain "sys2sys" in the username.