> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pillsoftware.com/llms.txt
> Use this file to discover all available pages before exploring further.

# In-checkout settings

> Configure checkout rules for house numbers, duplicate names, special characters, email typos, regex patterns, and field limits in AddressPill.

## In-checkout validation settings

Use this tab to define what AddressPill checks in checkout.

## How to enable

1. Open **Settings** in AddressPill.
2. Open **In-checkout validation**.
3. Turn the top toggle on.
4. Select your rules.
5. Click **Save settings**.
6. Confirm Shopify **Checkout rules** are enabled for AddressPill.

## Rules explained

* **Address validation (require house number)**: checks if a street number exists.
* **Check names (first and last name must differ)**: catches duplicate names.
* **Block special characters in address**: flags unusual symbols.
* **Check email typos**: catches common domain typos.
* **Block address with custom regex**: blocks patterns you define.
* **Length limits**: restricts max characters for address fields, names, and company.

For many rules, you can choose:

* **Show warning only**
* **Block checkout**

<Warning>
  If you are new, start with warnings first, then move to blocking rules after testing.
</Warning>

## FAQ

### What is the most important in-checkout rule?

Most merchants start with **require house number** because it prevents common delivery failures.

### Can I activate only some in-checkout rules?

Yes, you can enable only the rules you need and leave others off.

### Is it safe to block checkout immediately?

It is safer to start with warnings, validate behavior, and then block critical rules.