System-to-System Integration Patterns Flashcards

Which integration pattern uses a central component to query multiple backend services and combine their results into a single response for the caller?

Answer: Scatter-Gather

Scatter-Gather broadcasts a request to multiple recipients and aggregates their responses into one unified reply for the original requester.

What is the primary purpose of a 'Dead Letter Queue' (DLQ) in messaging-based integration?

Answer: Capturing messages that could not be processed successfully so they can be inspected and reprocessed

A DLQ holds messages that failed all processing attempts, enabling operations teams to investigate failures and replay messages after fixing the root cause.

In GraphQL federation, what integration problem does schema stitching solve?

Answer: Combining data from multiple GraphQL services into a single unified schema for clients

Schema stitching (and federation) merges schemas from multiple GraphQL services, allowing clients to query across service boundaries through a single endpoint.

Which integration anti-pattern occurs when point-to-point connections grow unmanageably between many systems, often called 'spaghetti integration'?

Answer: Full mesh / point-to-point sprawl

Point-to-point sprawl results in O(n²) connections as systems grow, creating a brittle, hard-to-maintain integration landscape often visualized as tangled spaghetti.

A 'Wire Tap' pattern in system integration is used to:

Answer: Intercept and copy messages to a secondary channel for monitoring without affecting the primary flow

Wire Tap transparently copies each message to a diagnostic or audit channel alongside the main channel, enabling logging and monitoring without altering the primary path.

When designing an integration that must handle schema evolution between a producer and consumer, which approach allows backward-compatible changes without breaking existing consumers?

Answer: Adding optional fields with default values while keeping existing fields intact

Adding optional fields with defaults is backward-compatible because existing consumers that don't know about new fields can still process the message correctly.

In a hybrid cloud integration scenario, which tool category primarily provides secure, managed connectivity between on-premises systems and cloud services?

Answer: Integration Platform as a Service (iPaaS)

iPaaS solutions (e.g., MuleSoft, Boomi, Azure Integration Services) provide pre-built connectors, secure tunneling, and managed runtimes for hybrid cloud integration.