Wells Fargo
Describes the Wells Fargo lockbox file format, which uses two fixed-width flat files (images.dat and optional fields.dat) to provide check MICR data, image paths, and operator-keyed remittance and invoice information.
How to identify this file
Two flat text files delivered together in a folder/archive:
images.dat — check (MICR) data
fields.dat — keyed-in remittance data (optional; if absent, no invoice data is extracted)
images.dat – Fixed-Width Field Mapping
Positions 14–23: Lockbox number
Positions 24–31: Deposit date (yyyyMMdd)
Positions 36–43: Batch number
Positions 47–49: Transaction ID
Positions 59–60: Document type
Must be "CK"
Non-CK records are skipped
Positions 61–74: Cheque amount
Positions 75–86: Cheque serial number
Positions 88–107: Routing number
Positions 108–127: Account number
Positions 128–180: Image path
fields.dat – Fixed-Width Field Mapping
Positions 14–23: Lockbox number
Positions 24–31: Deposit date
Positions 36–43: Batch number
Positions 47–49: Transaction ID (links to images.dat)
Positions 57–59: Field sequence number
Positions 61–96: Field name
Examples: INVOICE NUMBER, INVOICE AMOUNT, REMITTER NAME
Positions 98–133: Field value (keyed-in data)
Key considerations
Format type: Two fixed-width flat files (images.dat + fields.dat)
Keyed-in (remittance data)? Yes — fields.dat contains operator-keyed invoice and remitter data
Image files? Yes — image path in images.dat
What IS parsed: Check amount, routing, account, serial, lockbox/batch/date, image path (from images.dat); invoice number, invoice amount, remitter name (from fields.dat)
What is NOT parsed: Lines in images.dat where document type is not "CK" are ignored
fields.dat is optional. If missing, the check is still processed but without invoice or remitter data.