What is the 'Service Layer' pattern?
Updated Apr 28, 2026
Short answer
A boundary that defines available operations and coordinates the application's response in each operation.
Deep explanation
Middle-tier architecture often deals with reliability. Using a Circuit Breaker prevents a cascading failure where one slow service bogs down the entire system. Onion architecture ensures the core business logic remains independent of the database or external APIs.
Real-world example
A payment gateway middleware that retries a transaction only if it hasn't been processed yet (Idempotency).
Common mistakes
- Mixing business logic directly into the middleware, making it hard to test the core domain.
Follow-up questions
- How does a 'Sidecar' pattern relate to middleware?