Backend Integration Patterns

Professional Track: Complete this lesson with a working implementation, architecture notes, and a documented trade-off decision.

Overview

Backend integration is where product UX meets security and reliability constraints. Your Vue architecture must align with authentication, authorization, and contract lifecycle management.

Authentication and Session Patterns

  • Cookie-based session: stronger browser protections, needs CSRF handling.
  • Token-based flow: flexible across clients, requires careful storage and refresh strategy.

Refresh and expiry flow

if (response.status === 401) {
  await auth.refreshSession()
  return retryOriginalRequest()
}

Security Boundaries

CORS and CSRF basics

  • CORS controls cross-origin access policy.
  • CSRF protection is mandatory for cookie-authenticated mutation endpoints.
  • Do not expose internal tokens in logs or query parameters.

Frontend secret handling

Client apps do not protect secrets. Keep secret operations server-side and expose only necessary capabilities via API.

API Contract Lifecycle

Versioning and deprecation

Adopt explicit endpoint versioning and maintain migration windows so frontend releases are decoupled from backend deployments.

BFF pattern use cases

Use a backend-for-frontend layer when multiple backend services need orchestration, normalization, or policy control for one UI flow.

Learning Objectives

  • Implement authentication flows and token/session handling.
  • Apply CORS, CSRF, and API boundary best practices.
  • Use a BFF layer when frontend requirements diverge.

Common Mistakes

  • Confusing authentication with authorization and skipping server-side permission checks.
  • Hardcoding environment-specific API URLs across components.
  • Failing to align frontend error handling with backend status-code semantics.

Engineering Notes

Maintain a shared contract changelog between frontend and backend teams with version bump rules and rollout coordination.

Practice Scope

Deliver one production-style mini-feature, include implementation notes, and record one performance, reliability, or maintainability trade-off in your commit summary.

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