> For the complete documentation index, see [llms.txt](https://help.getalltool.com/king-checkout-validation/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.getalltool.com/king-checkout-validation/how-does-missing-house-number-work.md).

# How does "Missing House Number" work?

Ensure address Line 1 is not blank and has at least one number. If not, show an error and halt the process.

<figure><img src="https://3472108367-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FhCm3B02n2rLZWcOZM7ET%2Fuploads%2F7lEg3oO8MLJX2FrMfvnq%2FMissing%20House%20Number.gif?alt=media&amp;token=c0340aa2-3ee8-4a2d-8d41-175a185b622b" alt=""><figcaption></figcaption></figure>

**Note**: The rule check is triggered only after all Delivery fields are filled in.