Variables in GraphQL

Hardcoding values in queries works for testing, but production code should use variables.

Instead of:

query {
  user(id: 1) {
    name
  }
}

Use:

query GetUser($userId: ID!) {
  user(id: $userId) {
    name
  }
}

Then pass variables separately:

{
  "userId": "1"
}

Why variables?

• Reusability - Same query, different values
• Security - No string interpolation means no injection attacks
• Caching - Query structure stays constant, only values change

The $userId: ID! declares the variable type. The ! means it's required.

In Python, you pass variables as a dictionary alongside the query.

I explain variable patterns in my GraphQL with Python course.