GraphQL Introspection & API Discovery

Source: https://graphql.org/learn/introspection/, https://www.apollographql.com/docs/apollo-server/performance/apq/

Purpose

Discover the full schema of a GraphQL API at runtime using the introspection system — the primary mechanism for probing unknown GraphQL endpoints. Covers the standard introspection queries (__schema, __type, __typename), how to enumerate types/fields/queries/mutations, and how to use Automatic Persisted Queries (APQ) for efficient high-volume probing.

When to Use

• Probing an unknown GraphQL endpoint to enumerate all available types, queries, mutations, and fields
• Determining whether a GraphQL API has introspection enabled or disabled (production hardening check)
• Extracting schema documentation (type/field descriptions) from a live endpoint
• Navigating wrapper types (NON_NULL, LIST) to reach the actual inner types
• Reducing request overhead when repeatedly querying the same large introspection payload via APQ
• Building schema-aware tooling that dynamically adapts to any GraphQL API

Basic Usage