The sections below cover the file structure and the fields Lead uses for routing, matching, and funds movements.Documentation Index
Fetch the complete documentation index at: https://docs.lead.bank/llms.txt
Use this file to discover all available pages before exploring further.
File Structure
- Each X9 file contains one or more cash letters, each of which contains one or more bundles of check items.
- Each check item includes the front image, back image, and structured MICR data.
- Do not mix forwards and returns in the same X9 file.
Key Fields
The following fields are critical for correct processing:| Field | Notes |
|---|---|
| Settlement Date | Lead uses this date to determine when to move funds between the Fed GL and the Checks In Process GL. |
| Amount | Integer value in cents. Lead uses this for daily limit checks and funds movements. |
| Routing Number | Lead uses this to route incoming checks to the correct partner. For dedicated routing numbers, Lead forwards all items on the routing number to you. |
| OnUs Field (MICR) | Contains the account number. Lead uses this for item matching on shared routing numbers. Lead works with each partner to configure the structure of this field. |
| ECE Institution Item Sequence Number | A mandatory 15-digit field. Lead uses this to match incoming returns to the original outgoing entry. Populate it consistently on all outgoing X9 files. |
| Return Reason | Populated on return items. Indicates why a check is being returned — for example, an account closed or fraud detected. |
| Cash Letter ID | An eight-character alphanumeric identifier for the cash letter within the file. |
| BOFD Indicator | Bank of First Deposit indicator. Mandatory field; valid values are Y, N, or U. |