> For the complete documentation index, see [llms.txt](https://docs.langstack.com/welcome/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.langstack.com/welcome/get-started/learn-langstack/validation-pipeline/exercise-customer-information.md).

# Exercise: Customer Information

## Requirements

* A validation will be defined for the API “UserName\_Acc\_AddCustomer”. 
* When the API is executed and attempted to create or update an entity record, this validation will be called.
* Two (2) validations need to be applied through the Validation Steps: 
  * The first Validation Step checks if the mandatory fields of First Name, Last Name, Email, and Phone fields contain values. 
  * The second Validation Step checks if the Phone number digits count entered is between 7 and 10.
* An API gateway will be created, which uses this Validation pipeline. 
* The target entity is “UserName\_Acc\_customers”. 
* If the information entered is correct, a record will be created in the target entity. 
* If the information is missing or is not updated correctly, the record will not be created in the target entity and the error response will be responded back to the API.

## Solution

This exercise comprises the following steps: 

* Step 1: Create a Validation pipeline. 
* Step 2: Create an API gateway and define the Validation pipeline in the Entities tab.