Western Alliance Bank Positive Pay: Building Your Check Issue File
Western Alliance Bank offers positive pay to its commercial and business customers as a check fraud control. You send the bank a list of the checks you have issued, and the bank pays only the checks that match that list. Anything that does not match becomes an exception that you review and decide to pay or return. This page explains how positive pay works at Western Alliance Bank, what the check issue file generally contains, and how to build a file that matches your account using the free custom format builder on this site.
One important point up front: the exact check issue file layout is provided by the bank when you enroll, and it can vary by account and by service. Do not copy field positions from a generic template you found online. The details below describe the general shape of a positive pay file and the specific way Western Alliance Bank handles submission. Always confirm your first file against the format the bank gives you.
What positive pay at Western Alliance Bank covers
Western Alliance Bank publishes several related fraud controls under its treasury management services. According to the bank's own materials, the available services include:
- Check Positive Pay, which compares presented checks against your issued list, looking at the check number and amount.
- Check Payee Positive Pay, an add-on that also confirms the payee name before a check is released for payment.
- Reverse Positive Pay, where you review a list of all checks presented for payment and decide which to pay, instead of sending an issue file first.
- ACH Positive Pay and ACH Debit Block, which protect against unauthorized electronic debits rather than paper checks.
If you want to understand the difference between sending an issue file ahead of time and reviewing items after the fact, see positive pay vs reverse positive pay. The rest of this page focuses on Check Positive Pay and Check Payee Positive Pay, since those are the services that need a check issue file from you.
Where positive pay lives in the Western Alliance portal
Positive pay at Western Alliance Bank requires enrollment in Business Online Banking. That is the bank's commercial banking portal, and it is where you submit issue files, review exception items with check images, and approve or return them. The bank states that your check list can be handled three ways: uploaded into online banking, manually entered into online banking, or directly submitted by your ERP. When an exception is found, the bank notifies you by email or text message, and you review the check image online to make the pay or return decision before the cutoff.
A note on branding worth knowing if you bank with one of the legacy divisions: Western Alliance has long operated divisions such as Alliance Bank of Arizona, Bank of Nevada, and Bridge Bank under a single charter, and in 2025 the company announced it would unify those divisions under the single Western Alliance Bank brand. Your treasury management services and online banking access carry over, but the name on your portal and statements may have changed. If your file or login still references a division name, that is expected during the transition.
The general shape of a check issue file
Western Alliance Bank says it will provide you with a formatted template so you can list the checks you have issued. The exact columns, order, and format come from that template, so treat the following as the general field set rather than a precise spec. Most positive pay issue files, including bank-provided templates, are built from these elements:
- Account number, the checking account the checks are drawn on.
- Check or serial number, the number printed on each check.
- Amount, the dollar value, sometimes with the decimal implied so
1234.56is written as123456. See implied decimal amounts if your template requires this. - Issue date, the date the check was written, usually in a format like
MM/DD/YYYYorYYYYMMDD. - Action or status code, marking each row as issued or void. Voids matter because a voided check that is later presented should be flagged. See void checks in positive pay.
- Payee name, optional unless you use Check Payee Positive Pay, in which case the bank matches this against the printed payee. See payee positive pay.
For a fuller explanation of how these fields are arranged in fixed-width and CSV files, read the positive pay file format reference.
Building a matching file from your check register
Most accounting systems can export a check register, but the columns rarely line up with what the bank expects. That is the gap the free positive pay file generator closes. You define the layout once and reuse it every cycle.
- Export your check register from QuickBooks, Xero, your ERP, or a spreadsheet as a CSV.
- Open the custom format builder and recreate the layout from the template Western Alliance Bank gave you: set each field, its order, fixed-width or delimited, the date format, and whether the amount uses an implied decimal.
- Map your register columns to the bank's fields, including the issued or void action code.
- Generate the file and run it through the file validator to catch obvious problems before you upload.
- Upload it in Business Online Banking, or hand it to whoever submits the file from your ERP.
If a file ever comes back rejected, the usual causes are a wrong date format, a misplaced decimal, or a header the bank does not expect. The guide on a rejected positive pay file walks through fixing these.
Verify your first file with the bank
This is the step you should not skip. Because the layout is account-specific and comes from a template the bank issues, the only reliable way to confirm your file is correct is to send a small first file and have your Western Alliance Bank treasury contact confirm it loaded cleanly and matched. Do not assume a format you built from general guidance will work on the first try. Confirm field order, the date format, the amount format, and the issued and void codes directly against the bank's template and a real submission. You can review the official service description on the bank's site at Western Alliance Bank's positive pay page. Once your first file is verified, the same custom format will produce a correct file every cycle.