Compare REST and GraphQL API architectures.

REST: resource-based URLs, HTTP methods for operations, multiple endpoints, fixed data shapes, potentially over/under-fetching. GraphQL: single endpoint, client specifies exact data needed, reduces round trips, typed schema, introspection. REST: simpler, cacheable with HTTP, mature tooling. GraphQL: flexible queries, better for complex UIs, requires query complexity limits, caching more complex. REST suits simple CRUD; GraphQL suits complex, client-driven data needs.