Create a structurally valid test copy with sensitive data removed. Free, no signup, and your file is processed locally in your browser.
Primary topic: ACH file masker
The ACH file masker creates a safer test copy while preserving enough NACHA structure for demonstrations, debugging and development. Use this ACH file masker as a practical first step, then review its results carefully. treat masked output carefully because de-identification may be incomplete for unusual addenda or proprietary content.
A reliable ACH file masker workflow starts by confirming the business purpose before changing or exporting any data. This page is designed for creates a safer test copy while preserving enough NACHA structure for demonstrations, debugging and development. It performs the supported work locally, so the source does not need to be sent to a conversion service. Use the ACH file masker with an approved source and a clearly defined expected result.
Start with an ACH file containing names, routing numbers, account numbers, identifiers or other sensitive fields. Work from a copy, preserve leading zeros and remove unrelated report headings or totals that could be mistaken for transaction data.
Use the on-page controls, then compare the displayed batch count, entry count, total debits and total credits with the source expectation. Investigate warnings instead of assuming that a downloadable result is correct.
The expected result is a structurally valid masked copy with replacement values and rebuilt controls. Before transmission or downstream import, review that all sensitive fields are replaced, the output still validates and no original details remain in filenames or notes, save the source separately and follow your organization’s approval process.
Confirm that the selected input really contains an ACH file containing names, routing numbers, account numbers, identifiers or other sensitive fields. A renamed extension does not convert a spreadsheet, PDF or binary export into a valid ACH-related source.
Compare entries one batch at a time. Missing rows, duplicated rows, amount scaling, debit-versus-credit selection and malformed addenda can all change counts or monetary totals.
Format validation does not verify enrollment or bank policy. treat masked output carefully because de-identification may be incomplete for unusual addenda or proprietary content. Ask the ODFI for the rejection code and compare it with the company profile, identifiers and processing date.
It creates a safer test copy while preserving enough NACHA structure for demonstrations, debugging and development. The ACH file masker processes the data locally in your browser and does not require an account.
It needs an ACH file containing names, routing numbers, account numbers, identifiers or other sensitive fields. Files remain on your device during processing.
You will get a structurally valid masked copy with replacement values and rebuilt controls. Review the result before using it in an operational workflow.
Check that all sensitive fields are replaced, the output still validates and no original details remain in filenames or notes. Also remember that treat masked output carefully because de-identification may be incomplete for unusual addenda or proprietary content.
No. Processing creates a separate result in browser memory and leaves the source file unchanged. Keep the original as the audit baseline until the new output has been reviewed and accepted.
Confirm that the files share compatible originator and processing settings, then review that all sensitive fields are replaced, the output still validates and no original details remain in filenames or notes. Do not rely on matching filenames or creation dates alone.
When the tool creates a new ACH output, it rebuilds affected counts, hashes, debit and credit totals, batch controls, file controls, block count and padding from the resulting entries.
Preserve the source, review a preview, validate the output and obtain any required approval before transmission. treat masked output carefully because de-identification may be incomplete for unusual addenda or proprietary content.
Technical explanations are checked against these primary sources. Bank-specific requirements can be narrower than general format guidance.
Sources reviewed August 20, 2026. Nacha owns and maintains the linked materials.
ACH files use the NACHA fixed-width format: every record is 94 characters, files contain one or more batches, and control records reconcile entry counts, routing-number hashes, debits and credits. Always confirm bank-specific settings with your financial institution before uploading a production file.