Backend Starter
If I’m hiring a backend developer and I want them to be immediately productive, there are a few non-CS fundamentals I would require expertise in, depending on the maturity and scale of the system. Here are the most impactful backend-specific domains that I’d lean heavily on:
🚨 Must-Have Domain Expertise (Beyond CS Basics)
Section titled “🚨 Must-Have Domain Expertise (Beyond CS Basics)”1. Data Modeling + Query Optimization (SQL)
Section titled “1. Data Modeling + Query Optimization (SQL)”-
Not just CRUD.
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Must be able to:
- Design normalized + denormalized schemas based on use case.
- Understand query plans and indexes.
- Optimize slow queries.
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Why: Backend work is often bottlenecked by bad data access patterns more than bad code.
2. API Design + Versioning Principles
Section titled “2. API Design + Versioning Principles”-
Knows REST vs GraphQL tradeoffs.
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Understands:
- Contract stability.
- Pagination, filtering, error handling.
- Breaking vs non-breaking changes.
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Why: Poor API design causes years of tech debt and pain.
3. Authentication + Authorization (OAuth2/OIDC/Role-based access control)
Section titled “3. Authentication + Authorization (OAuth2/OIDC/Role-based access control)”- Knows how token-based systems work (JWT vs opaque).
- Can implement scopes, roles, tenants, etc.
- Why: Backend devs deal with access control daily, and mistakes here lead to security breaches.
4. Observability / Debuggability
Section titled “4. Observability / Debuggability”- Fluent in logs, traces, and metrics.
- Can instrument code with structured logs.
- Why: Debugging distributed systems is brutal without this. It’s where junior devs waste the most time.
5. Job Queues / Async Processing
Section titled “5. Job Queues / Async Processing”- Knows when to offload to background jobs.
- Has experience with queues (e.g., RabbitMQ, Kafka, SQS) and workers.
- Why: Backends need to scale beyond just HTTP request lifecycles.
👑 Bonus That Makes Them Senior Fast
Section titled “👑 Bonus That Makes Them Senior Fast”- Caching Strategies
Section titled “- Caching Strategies”- Knows what to cache (and what not to).
- Can use Redis, CDNs, in-memory caches wisely.
- Understands invalidation techniques.
- Distributed Systems Fundamentals
Section titled “- Distributed Systems Fundamentals”- Knows CAP theorem, consistency models.
- Familiar with leader election, retries, idempotency, etc.
- Especially if the system spans multiple services or regions.
- Containerization + Deployment (Docker/K8s)
Section titled “- Containerization + Deployment (Docker/K8s)”- Can write a clean Dockerfile and debug container failures.
- Doesn’t need to be infra-heavy, but must understand how their app runs in prod.
Summary: If I had to pick one, I’d require data modeling + query optimization. It has the highest ROI for backend dev productivity, especially in systems that touch any non-trivial data.