> Note:
> The REST Admin API is a legacy API as of October 1, 2024. All apps and integrations should be built with the [GraphQL Admin API](/docs/api/admin-graphql). For details and migration steps, visit our [migration guide](/docs/apps/build/graphql/migrate).




You can simplify GraphQL queries and mutations by extracting data into separate variables. GraphQL variables let you reuse the same requests with different arguments.

## Variable structure

GraphQL requests can be split into query and variable sections.

### Query section

In the query section, GraphQL variables begin with the `$` symbol and are declared after the `query` or `mutation` keyword, similar to passing an argument to a function.

When you declare a variable, you need to specify its type, such as [`CustomerInput`](/docs/api/admin-graphql/latest/input-objects/CustomerInput). This lets GraphQL know that you intend to refer to this type by this variable name later in the actual query.

For example, the following query declares an `$input` variable and passes it to the `input` argument:


```graphql
mutation($input: CustomerInput!) {
  customerCreate(input: $input) { ... }
}
```



### Variable section

In the variable section, variables are defined as a JSON object.

The following JSON object defines the `$input` variable for the query section:


```json
{
  "input": {
    "firstName": "Ayumu",
    "lastName": "Hirano",
    "email": "ayumu@example.com"
  }
}
```



## Simplify the customer creation request

The following example simplifies the [`customerCreate` mutation example](/docs/apps/build/graphql/basics/mutations#example-create-a-customer) by using variables, resulting in an abstracted mutation that can be reused to create multiple customers.


```graphql
mutation ($input: CustomerInput!) {
  customerCreate(input: $input)
  {
    customer {
      id
      displayName
    }
    userErrors {
      field
      message
    }
  }
}
```



```json
{
  "input": {
    "firstName": "Ayumu",
    "lastName": "Hirano",
    "email": "ayumu@example.com"
  }
}
```




```json
{
  "data": {
    "customerCreate": {
      "customer": {
        "id": "gid://shopify/Customer/1310038130710",
        "displayName": "Ayumu Hirano"
      },
      "userErrors": []
    }
  }
  ...
}
```




## Next steps

Learn how to optimize your GraphQL implementation further with [inline fragments and multi-query requests](/docs/api/usage/graphql-basics/advanced).