bff-architecture-and-api-aggregation

BFF Architecture And API Aggregation

Use When

• Frontend depends on multiple backend services per screen
• Different clients (web, mobile, partner) need tailored payloads

Workflow

1. Define client-specific BFF boundary and ownership.
2. Design response contracts optimized for UI rendering.
3. Implement upstream call orchestration with timeouts and fallbacks.
4. Add partial-failure handling and graceful degradation.
5. Measure end-to-end latency and payload efficiency.

Required Checks

• BFF does not duplicate core domain business rules
• Upstream failure handling is deterministic
• Aggregated endpoint performance budget is documented

Decision Framework

• Prefer explicit contracts and compatibility rules before implementation.
• If dependency risk is high, require timeout, retry, and fallback strategy per call path.
• If async messaging is used, require idempotency, replay, and dead-letter handling.
• If traffic patterns are volatile, require load, failover, and scaling validation before ship.

Common Rationalizations And Rebuttals

• "Retries will handle failures automatically." -> Unbounded retries can amplify outages; use budgets.
• "We can skip runbooks for now." -> Operational ambiguity delays incident recovery.
• "Contract changes are minor." -> Small breaking changes cause broad downstream regressions.

Evidence Pack

• Contract compatibility note and migration strategy (if applicable)
• Failure-mode test evidence for dependency degradation and recovery
• Observability snapshot (latency, error, saturation, or queue health)
• Rollout and rollback steps with clear trigger thresholds

Exit Criteria

• Client complexity decreases without coupling domain services
• BFF reliability is observable and operable