> For the complete documentation index, see [llms.txt](https://docs.infotopics.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.infotopics.com/writebackextreme/features/tableau-extension/configuration/schemas/general-features/field-masking.md).

# Field masking

Automatically format user input to match expected patterns (e.g., phone numbers)

**Field Masking** allows you to define an input format that automatically structures user input as they type, ensuring clean, consistent data every time.

***

#### 🧠 What it does

Masking improves the user experience and enforces correct formatting without requiring the user to think about it.

When applied, the form **guides the user visually** by formatting the input according to a defined mask pattern.

<figure><img src="https://content.gitbook.com/content/0gkOLIfzuEyMP2kvoT9o/blobs/VM0S3jvMKx3wCRNiVduV/image.png" alt="" width="375"><figcaption></figcaption></figure>

#### Use Cases

* Phone numbers with international formatting
* Postal codes (e.g., Dutch format `1234 AB`)
* Social security numbers or tax IDs
* IBAN or credit card numbers (auto-grouped by 4 digits)
* Dates (e.g., `DD/MM/YYYY`)

<figure><img src="https://content.gitbook.com/content/0gkOLIfzuEyMP2kvoT9o/blobs/0CC7BAzWuFmwpg2jcgIS/image.png" alt=""><figcaption></figcaption></figure>

Here’s how Field Masking looks in action:

* **Phone number field**: Automatically formats input as\
  `+12 (312) 312-3123`\
  This prevents inconsistent number formatting and simplifies international phone number entry.
* **Postal Code field**: Enforces a structure like\
  `1234 DD`\
  Ensuring that postal codes are correctly entered with both numbers and letters in the required layout.

<figure><img src="https://content.gitbook.com/content/0gkOLIfzuEyMP2kvoT9o/blobs/tVSvzu0k5FvLasmlPSKk/image.png" alt="" width="536"><figcaption></figcaption></figure>

#### Why it matters:

* Consistent input formatting
* Fewer user errors
* No need for manual data cleanup
* Better alignment with back-end validation

> 🔄 Combine this with **Field Validation (Regex)** for even stronger input control and custom error messages.


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