Backend Engineering
Build robust backends: REST APIs, authentication, gRPC, caching, and system design.
Backend ownership at senior levels means APIs, auth, state, and scaling—and the failures here are visible: outages, security incidents, and "it works on my machine" in production. Interviewers and peers probe whether you understand how services communicate, where state lives, and how to scale under real constraints.
These topics build a rigorous mental model of boundaries, consistency, and failure modes—so you can design and operate backends, diagnose issues under pressure, and explain trade-offs clearly. You'll signal that you own the full request path, not just the handler.
Topics in this category
API Design: Versioning, Errors, Pagination & Best Practices
Read →Design scalable APIs: versioning, pagination, errors, rate limits, idempotency, and practical REST conventions.
API Documentation: OpenAPI, Examples & Developer Experience
Read →Write clear API docs with OpenAPI/Swagger, examples, auth flows, error contracts, and keeping docs in sync.
API Filtering & Sorting: Query Design, Indexing & Safety
Read →Build robust list endpoints: filters, sorting, pagination interplay, index strategy, validation, and abuse prevention.
API Pagination: Cursor vs Offset, Consistency & Performance
Read →Implement pagination correctly: cursor vs offset, stable ordering, backfills, consistency, and performance trade-offs.
Authentication & Authorization: JWT, OAuth, RBAC & Security
Read →Secure systems with authn/authz: sessions vs JWT, OAuth flows, RBAC/ABAC, token rotation, and threat basics.
Background Jobs & Queues: Retries, DLQs, Ordering & Backpressure
Read →Run work async with queues: retries, DLQs, idempotency, scheduling, priorities, ordering, and backpressure.
Caching Strategies (Backend Fundamentals)
Read →Learn caching basics: read-through vs write-through, TTLs, invalidation, and when caches help or hurt.
Circuit Breakers: Prevent Cascades & Handle Dependency Failure
Read →Use circuit breakers to prevent cascading failures: states, thresholds, fallbacks, and how they pair with retries/timeouts.
Content Negotiation: Accept Headers, Versioning & Formats
Read →Serve multiple formats safely: Accept/Content-Type, versioning strategies, caching, and pitfalls with clients.
Database Connection Pooling: Sizing, Timeouts & Failure Modes
Read →Tune connection pools: sizing, timeouts, queueing, max connections, and avoiding thundering herds under load.
Error Handling & Logging: Reliability, Debugging & Observability
Read →Handle errors well: typed errors, retries, logging strategy, correlation IDs, and practices that speed debugging.
Graceful Shutdown: Draining, Timeouts & In-Flight Requests
Read →Shut down safely: signal handling, connection draining, in-flight requests, timeouts, and load balancer coordination.
Health Checks & Monitoring: Liveness, Readiness & Alerts
Read →Implement health checks: liveness vs readiness, dependency checks, alerting, and avoiding false positives.
Message Queues: Ordering, Delivery Guarantees & Patterns
Read →Use queues well: pub/sub vs queues, ordering, retries, dead-letter queues, and delivery guarantees.
Rate Limiting & Throttling: API Protection & Trade-offs
Read →Protect APIs from abuse: rate limiting vs throttling, algorithms, distributed enforcement, and implementation trade-offs.
Request Batching: Performance, Rate Limits & Trade-offs
Read →Improve performance with batching: when to batch, sizing, latency trade-offs, and avoiding head-of-line blocking.
Request Timeouts: Prevent Cascades & Resource Exhaustion
Read →Handle timeouts in distributed systems: budgets, retries interplay, cascading failures, and safe defaults.
Request Validation: Schemas, Sanitization & Security
Read →Validate inputs safely: schemas, sanitization, rate limits, auth checks, and preventing injection and abuse.
REST vs GraphQL: Choosing the Right API Style
Read →Choose REST or GraphQL: caching, performance, tooling, versioning, and when each approach fits best.
Webhooks: Delivery Guarantees, Retries & Security
Read →Implement reliable webhooks: retries, idempotency, signing, replay protection, and handling delivery at scale.
WebSockets & Real-Time: Connections, Scaling & Protocols
Read →Build real-time systems with WebSockets: connection management, message protocols, scaling, and fallback strategies.