ACH File Converter

ACH File Masker

Create a structurally valid test copy with sensitive data removed.

1

Source ACH/NACHA file

Check the sanitized test file

Browse all tools

Continue with a tool that fits the next step in this workflow.

Data replaced in a masked copy

Sensitive names, account values, identifiers, and payment-related text are substituted in the downloadable copy. The original is not overwritten.

Structure retained for testing

Record types, hierarchy, field widths, batch relationships, addenda relationships, and recalculated controls remain available for parser and workflow tests.

What to inspect before sharing

  • Search raw records for real names and identifiers.
  • Review free-form addenda and discretionary data.
  • Confirm routing and account substitutes are fictitious.
  • Validate the masked output after controls are rebuilt.

When fully synthetic data is safer

Use the sample generator when a test does not depend on the shape of a real file. Masking reduces exposure, but a source-derived file can retain operational patterns or overlooked free text.

Questions about masking ACH data

Is masking the same as encryption?

No. Masking replaces values in a test copy; encryption protects data using a key.

Will the masked file remain structurally valid?

The workflow preserves field widths and rebuilds dependent controls, but validate the result before using it in a test.

Can I share a masked file publicly?

Review it first. Free-form fields and organizational patterns may still be sensitive even after standard fields are replaced.

Which authoritative sources support this page?

Technical explanations are checked against these primary sources. Bank-specific requirements can be narrower than general format guidance.

  1. Nacha ACH File Details — Official record-field guidance, including Batch Header SEC codes and addenda capabilities.
  2. Nacha ACH File Overview — Official explanation of files, batches, entries, controls, and batch grouping.
  3. Nacha: How ACH Works — Official overview of ACH participants, consumer and corporate payments, and authorization responsibilities.
  4. Nacha Operating Rules Topics — Current rule changes and implementation topics published by Nacha.

Sources reviewed August 20, 2026. Nacha owns and maintains the linked materials.