api-graphql-resolver

To implement a Magento 2 GraphQL resolver, define the mutation in your schema.graphqls and create a resolver class that validates input, enforces authorization, and delegates execution to service contracts. This ensures thin resolvers without leaked transport concerns.

Adding authorization checks to Magento 2 GraphQL queries involves enforcing customer and admin access rules directly within the resolver class before delegating to repositories. Denied access attempts are thrown as structured GraphQL exceptions for predictable API behavior.

Handling GraphQL errors in Magento 2 resolvers requires throwing specific GraphQL exceptions for invalid input, missing entities, and denied access. This approach delivers structured failure responses to clients, maintaining a backward-compatible and error-safe API.

You need a thin resolver delegation pattern in Magento GraphQL when mapping schema fields to services to prevent leaking transport concerns into business logic. Resolvers focus strictly on input validation and authorization while delegating execution to service contracts.

Schema-first design works for extending Magento 2 GraphQL endpoints by defining or modifying types, queries, and mutations in schema.graphqls with explicit resolver bindings. This enables structured response shaping and backward compatibility for custom modules.