Explain the Composite API family. What are the differences between composite request, sObject tree, batch, and graph?

The Composite API family allows multiple REST API calls in a single HTTP request, reducing round trips:

Composite Request: Execute up to 25 sub-requests sequentially. Each sub-request can reference the response of a previous one using @{referenceId}. Supports mixed object types. All requests share one governor limit context. If one fails and allOrNone: true, all are rolled back.

sObject Tree: Create up to 5 parent records and their related children (up to 200 records total) in one call. Ideal for inserting a hierarchy (e.g., Account + Contacts + Opportunities) atomically.

Composite Batch: Execute up to 25 independent sub-requests. Requests do NOT share context — each is processed independently. No cross-referencing between requests. Failures do not roll back others.

Composite Graph: Execute multiple independent composite graphs in one request. Graphs within a request are independent; sub-requests within a graph can cross-reference each other. More powerful than composite request for complex dependency trees.