The MaskType property is a newer and more powerful alternative to ExtendedDatatype = Masked.

It defines whether a field’s value should appear concealed in the user interface — but unlike the older version, it provides a Hide/Show eye icon 🔒👁️‍🗨️ that lets users toggle visibility.

This property gives end users control to reveal or conceal sensitive information temporarily, improving usability without custom actions or control add-ins.

The value appears concealed (••••••) by default.

A small 👁️ eye icon appears next to the field, allowing the user to reveal or hide the value.

When revealed, the actual text is displayed; when hidden, dots appear again.

Works for the following field types: Text, Code, Decimal, Integer, BigInteger.

The “Confidential Note” field appears as dots with an eye icon 👁️ beside it. Clicking the icon reveals or hides the real text.

MaskType = Concealed is the modern way to handle field masking in Business Central.

It provides better user experience, a built-in toggle, and supports numeric fields too.

Still, it’s a UI-layer protection only — for sensitive data, pair it with permission sets or encryption.

MaskType can't be defined together with the ExtendedDatatype Property set to Masked, this will throw an error. Also, the MaskType property isn't allowed in repeater controls and in ConfigurationDialog pages.

It is not enabled by default. To use it in both standard and custom objects, you must first enable it in Feature Management.