What is backendforfrontend?

A Backend‑for‑Frontend (BFF) is a special type of server that sits between a user interface (like a mobile app or web page) and the main backend services. Instead of the UI talking directly to many different APIs, it talks to one tailored backend (the BFF) that knows exactly what that UI needs and formats the data accordingly.

Let's break it down

  • Frontend: the part of an app you see and interact with (React web app, iOS app, etc.).
  • Backend: the services that store data, run business logic, and expose APIs.
  • BFF: a thin layer built just for one kind of frontend. It receives requests from that UI, calls the necessary backend services, reshapes or aggregates the data, and sends a response that the UI can use directly.

Why does it matter?

  • Simplifies the UI code: the frontend gets data in the exact shape it needs, so it doesn’t have to stitch together multiple API calls.
  • Improves performance: the BFF can combine several backend calls into one, reducing network round‑trips.
  • Enables UI‑specific logic: things like pagination, caching, or security rules that differ between a mobile app and a web app can be handled in the BFF without polluting the core services.
  • Decouples frontends from backend changes: if a backend API changes, only the BFF may need updating, keeping the UI stable.

Where is it used?

  • Large companies with multiple client types (e.g., a web portal, iOS app, Android app) often create a separate BFF for each.
  • Projects that need to aggregate data from several microservices into a single response for the UI.
  • Situations where the UI requires custom authentication or rate‑limiting that differs from the main API.
  • Any architecture that follows microservices but still wants a clean, simple contract for each client.

Good things about it

  • Tailored responses: each UI gets exactly what it asks for, no extra fields.
  • Reduced frontend complexity: less code for handling multiple calls, error handling, and data transformation.
  • Better performance: fewer network hops, possible server‑side caching, and batch requests.
  • Isolation of concerns: UI‑specific concerns stay in the BFF, keeping core services focused on business logic.
  • Easier versioning: you can evolve the BFF independently for each client without breaking others.

Not-so-good things

  • Additional layer to maintain: you now have another service to develop, test, deploy, and monitor.
  • Potential duplication: similar logic may appear in multiple BFFs if many frontends need the same data.
  • Latency overhead: if not designed well, the extra hop can add delay instead of reducing it.
  • Complexity in routing: deciding what belongs in the BFF versus the core backend can be tricky and may lead to blurred boundaries.
  • Scalability concerns: each BFF must be scaled separately, which can increase infrastructure costs.