> ## Documentation Index
> Fetch the complete documentation index at: https://docs.truv.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Day 1 Certainty (D1C)

> Day 1 Certainty validation through Desktop Underwriter for income, employment, and assets

Truv is an authorized report supplier for Fannie Mae's [Desktop Underwriter](https://singlefamily.fanniemae.com/applications-technology/desktop-underwriter) (DU). Truv reports provide representation and warranty relief on validated loan components: income, employment, and assets.

Truv's vendor ID is **Truv**.

## How it works

```mermaid theme={null}
sequenceDiagram
    participant Borrower
    participant Lender
    participant Truv
    participant DU as Fannie Mae DU

    Lender->>Truv: Create order (VOIE + VOA)
    Truv->>Borrower: Launch Bridge widget
    Borrower->>Truv: Connect payroll & bank accounts
    Truv->>Lender: Webhook: verification complete
    Lender->>Truv: Retrieve Report ID
    Lender->>DU: Submit loan with Report ID
    DU->>Truv: Fetch report data
    DU->>Lender: DU Findings (D1C eligible)
```

***

## Day 1 Certainty eligibility

Official Fannie Mae resource: [Desktop Underwriter](https://singlefamily.fanniemae.com/applications-technology/desktop-underwriter)

D1C provides:

* **Rep and warranty relief** on income, employment, and assets
* **Reduced documentation** requirements
* **Free re-verifications** for up to 90 days after the initial report

<Note>
  **"Current as of" date:** For DU, this reflects the end of period from the borrower's last pay statement.
</Note>

***

## Implementation checklist

Use this sequence for a production-ready Fannie Mae flow:

1. Complete your Truv integration using [LOS integrations](/mortgage/integration/los-overview) or [Custom Integration](/mortgage/integration/custom-pos)
2. Collect borrower income and, when needed, asset verification through Truv
3. Retrieve the latest `voie_report_id` and `voa_report_id`
4. Submit the Report ID into Desktop Underwriter
5. Validate DU findings and confirm Day 1 Certainty eligibility
6. If data is refreshed, use the newest Report ID for resubmission

***

## Integrate with Encompass

For [ICE Encompass](/mortgage/integration/ice-encompass) clients, Truv's Report ID appears in the **Loan: GSE Additional Provider Data** screen as **Truv (Bor, CoBorr)**.

### VOIE field mapping

Write the Report ID to Encompass FieldID `GSEVENDOR.X50`. For borrower and coborrower, comma-separate the Report IDs:

```
borrower_report_id,coborrower_report_id
```

### VOA field mapping

| Borrower        | Coborrower      |
| --------------- | --------------- |
| `GSEVENDOR.X37` | `GSEVENDOR.X38` |

***

## Validation checklist

<Steps>
  <Step title="Verify report generation">
    Confirm Truv generated the latest VOIE and VOA reports and that the borrower completed all required verifications before you submit to DU.
  </Step>

  <Step title="Confirm field mapping">
    If you use Encompass, verify `GSEVENDOR.X50`, `GSEVENDOR.X37`, and `GSEVENDOR.X38` are populated correctly before DU submission.
  </Step>

  <Step title="Submit to DU">
    Submit the current Report ID in Desktop Underwriter and confirm DU can retrieve the report successfully.
  </Step>

  <Step title="Review DU findings">
    Check for Day 1 Certainty eligibility, missing data, or any partial-validation conditions caused by incomplete borrower verification.
  </Step>
</Steps>

***

## Test in sandbox

For DU-oriented borrower test accounts, pre-generated VOIE and VOA report IDs, and sample report PDFs, see [GSE Testing](/developers/testing/gse-testing). For the general payroll credential matrix and non-GSE scenarios, see [Income & Employment Testing](/developers/testing/income-employment) and [Assets Testing](/developers/testing/assets).

***

## Next steps

<CardGroup cols={2}>
  <Card title="Asset and Income Modeler (AIM)" icon="building-columns" href="/mortgage/d1c-aim/freddie-mac">
    Freddie Mac Loan Product Advisor integration
  </Card>

  <Card title="Sample Reports" icon="file-contract" href="/mortgage/testing/sample-reports">
    Shared report retrieval patterns and Encompass mappings
  </Card>

  <Card title="Sandbox" icon="flask" href="/developers/testing/test-credentials">
    Sandbox credentials and test scenarios
  </Card>

  <Card title="Launch Checklist" icon="list-check" href="/developers/testing/launch-checklist">
    Pre-production validation
  </Card>
</CardGroup>