Who this is for
- People who enjoy building the invisible backbone of apps: data, APIs, and reliability.
- Developers moving from frontend, scripting, or QA into infrastructure and services.
- Career changers comfortable with logic, systems thinking, and patient debugging.
Prerequisites
- Comfortable with at least one programming language (e.g., JavaScript/TypeScript, Python, Java, Go, C#).
- Basic command line usage and Git.
- Understanding of HTTP and JSON.
Quick self-check (no pressure)
- Can you explain what an HTTP request and response look like?
- Have you used Git to branch, commit, and merge?
- Have you written a script or small program that reads/writes files or calls an API?
What a Backend Engineer does
Backend Engineers design, build, and operate the server-side of software. You focus on APIs, databases, integrations, scalability, and reliability.
- Design and implement APIs that are clear, secure, and fast.
- Model data and write queries that are correct and efficient.
- Integrate with internal and external services (payments, auth, messaging).
- Plan for performance, caching, and scalability.
- Automate build, test, and deployment pipelines; monitor systems in production.
- Write docs, review code, discuss trade-offs, and handle incidents.
A day in the life (example)
- Standup: share progress, blockers, and today’s plan.
- Focus block: implement a new endpoint and its tests.
- Design review: discuss database changes for an upcoming feature.
- Debug: investigate a latency spike using logs, metrics, and traces.
- Infra: update CI pipeline to run integration tests in parallel.
- Docs: write API usage notes and release summary.
Where you can work
- Industries: fintech, e-commerce, SaaS, healthcare, gaming, media, government, education, logistics.
- Team types: product teams, platform/core services, data platform, SRE/ops-adjacent roles.
- Company sizes: startups (generalist), scale-ups (service ownership), enterprises (specialized domains).
Hiring expectations by level
Junior
- Implements well-scoped tasks with guidance.
- Writes simple APIs, CRUD queries, and unit tests.
- Understands code reviews and basic debugging.
- Portfolio: 2–3 small services and a clear README.
Mid-level
- Owns features end-to-end from design to deploy.
- Makes schema changes, adds indexes, and considers performance.
- Designs APIs that are versioned and well-documented.
- Participates in on-call with guidance; proposes improvements.
Senior
- Leads system design and cross-team integrations.
- Improves reliability (SLOs, capacity planning, incident response).
- Mentors others, raises engineering standards and velocity.
- Makes pragmatic build/buy/iterate decisions with trade-offs.
Salary ranges (rough)
- Junior: roughly $55k–$90k USD
- Mid-level: roughly $85k–$140k USD
- Senior: roughly $130k–$200k+ USD
Varies by country/company; treat as rough ranges.
Skill map
- Backend Engineering Foundations: Core language, HTTP, JSON, testing, Git.
- API Development: REST/gRPC design, versioning, auth, pagination.
- Database Design And Access: Data modeling, SQL/ORMs, indexing, transactions.
- System Design Basics: Caching, queues, consistency, scaling patterns.
- Performance And Reliability: Latency, throughput, timeouts, retries, circuit breakers.
- Microservices And Integration: Service boundaries, contracts, messaging, idempotency.
- Security And Compliance: Secrets, authN/Z, input validation, data minimization.
- CI CD And DevOps Basics: Pipelines, testing stages, environments, deployments.
- Observability And Operations: Logs, metrics, traces, alerts, SLOs, on-call.
- Documentation And Collaboration: ADRs, READMEs, runbooks, clear proposals.
Learning path
- Foundations: Refine your main language, HTTP/JSON, and testing basics.
Mini task
Write a tiny service with one endpoint that returns version info and current time. Add a unit test.
- APIs + Database: Build REST endpoints on top of a relational DB, including pagination and validation.
Mini task
Create a /users endpoint with POST/GET, store to a DB, and add an index for email.
- System design + Reliability: Add caching, rate limits, and graceful timeouts. Practice reading logs and metrics.
Mini task
Add a simple in-memory cache with TTL; log cache hits/misses and compare latency.
- Operations + Collaboration: Wire a CI pipeline, write runbooks, and practice incident response drills.
Mini task
Make CI run tests on every push and block merges on failures. Write a short runbook for your service.
Practical projects (portfolio-ready)
1) Task Tracker API
- Scope: CRUD for projects and tasks; users can list, filter, and complete tasks.
- Acceptance: Auth, pagination, validation, error handling, OpenAPI spec, seed data.
- Stretch: Background job to send reminders; add rate limiting and a cache layer.
2) URL Shortener with Analytics
- Scope: Create short links, redirect, count clicks.
- Acceptance: Unique codes, 301 redirects, per-link metrics (clicks/day, referrer, country).
- Stretch: Expiring links, custom domains, write-ahead log and retries for metrics.
3) E-commerce Checkout (Mock)
- Scope: Cart, checkout, order creation, inventory reservation.
- Acceptance: Idempotent order creation, transactional updates, compensating logic on failure.
- Stretch: Async order confirmation email via queue; saga pattern for payment + inventory.
4) Feed Service
- Scope: Follow users, publish posts, read personal feed.
- Acceptance: Event-driven fan-out, eventual consistency, cursor pagination.
- Stretch: Caching hot timelines, backfill job, anti-stampede measures.
5) Incident Simulator
- Scope: Inject timeouts and errors to test resiliency.
- Acceptance: Timeouts, retries with jitter, circuit breaker, dashboard with error rate/latency.
- Stretch: Runbook with mitigation steps; add synthetic checks and alerts.
Interview preparation checklist
- Explain trade-offs for REST vs gRPC and pagination strategies.
- Walk through data modeling choices and indexes for a sample feature.
- Whiteboard or narrate a design for a read-heavy service with caching and replicas.
- Discuss reliability patterns: timeouts, retries, backoff, circuit breakers.
- Security basics: authN vs authZ, SQLi prevention, storing passwords safely.
- Operational readiness: CI stages, deployment strategies, runbooks, alerting noise control.
- Behavioral: ownership, incident learning, cross-team collaboration.
Practice prompt
Design a rate-limited, paginated public API for listing articles. Consider versioning, caching, and abuse prevention. Outline endpoints, data model, and error codes.
Common mistakes (and how to avoid them)
- Skipping tests: Add unit tests for core logic and happy-path API tests in CI.
- Under-indexing or over-indexing: Measure queries, add targeted indexes, verify with EXPLAIN.
- Ignoring timeouts: Set client and server timeouts; add retries with exponential backoff and jitter.
- Poor error handling: Standardize error shapes; log with context; avoid leaking sensitive data.
- Silent breaking changes: Version APIs; deprecate with notices; support dual versions during migration.
- Opaque systems: Add logs, metrics, traces; define SLOs and alert only on symptoms that matter.
Next steps
Pick a skill to start. Build one small project per skill, and keep notes on design trade-offs. When ready, try the exam below to gauge your readiness. Progress is saved for logged-in users; everyone can take it.