Deliver loan closing data to Fannie Mae and Freddie Mac using the Uniform Closing Dataset v2.0 API

Steps

1. Generate a UCD v2.0 compliant XML file from the closing disclosure data in the LOS, using the UCD v2.0 schema published by the GSEs and validating against the Phase 3B and Phase 4 critical edit rules now active in production since September 2025
2. Authenticate to the Fannie Mae UCD Collection Solution API using lender credentials and POST the UCD XML file, receiving a Fannie Mae Document File ID in the response
3. Authenticate to the Freddie Mac Loan Closing Advisor via its API or UI and submit the same UCD XML file, receiving a Freddie Mac Document File ID
4. Check the submission summary from each GSE for any fatal edits; resolve and resubmit if fatal edits are present—warning edits in the current phase do not block delivery but are expected to become fatal in Phase 4B
5. Store both GSE-issued document file IDs in the LOS and include them in the loan delivery data file (ULDD) when selling the loan to each respective GSE
6. Monitor GSE announcements for the Phase 4A and 4B critical edit subset release planned for Q1 2026, which will tighten closing data quality requirements and may require additional LOS field mapping