Free Learning Roadmap

How to Become a Software Engineer

The generalist trunk that backend, frontend, full-stack, and platform careers fork from. Deep foundations in code, systems, and shipping product.

Topics
12
Resources
57
Cost
Free
Most resources are free or freemium
Format
Self-paced

1. Programming Fundamentals

core
A Primary Language, Deeply

Pick one — Python, TypeScript, Go, Java, C# — and get past syntax. Understand its memory model, concurrency model, and error handling.

Data Structures & Algorithms

Arrays, hashmaps, trees, graphs, dynamic programming — not just for interviews. Knowing when a hashmap collapses O(n²) to O(n) is table stakes.

Clean Code & Refactoring

Names that don't lie, functions that do one thing, tests that document behaviour. The daily discipline that separates seniors from juniors.

2. Version Control & Collaboration

core
Git Fluency

Beyond commit/push — rebase, cherry-pick, bisect, reflog. When production is broken and you need to find the commit that did it, this is what you reach for.

Code Review

Writing PRs that are easy to review, reviewing PRs kindly and rigorously. This is where team culture is transmitted.

3. Computer Science Foundations

core
Operating Systems

Processes, threads, memory management, filesystems, syscalls. Explains every weird production behaviour you'll ever encounter.

Networking Basics

TCP/IP, HTTP, DNS, TLS. When your service can't reach another service, this is what you debug.

4. Systems Design

core
Design Fundamentals

Latency, throughput, availability, consistency. The five words every senior interview loop hinges on.

Caching Strategies

Cache invalidation is one of the two hard things. Learn Redis, cache aside, write-through, TTLs, and stampede prevention.

Monolith vs Microservices

The industry has swung back toward modular monoliths. Understand when each shape actually serves the team, not the résumé.

5. Testing

core
Unit Tests

Fast, deterministic, isolated. AAA (arrange-act-assert), test doubles, table-driven tests.

Integration & End-to-End Tests

The tests that catch what unit tests miss. Docker Compose, testcontainers, Playwright, Cypress.

6. Databases

core
SQL

Every backend engineer writes SQL. Master joins, aggregations, window functions, and reading EXPLAIN plans.

NoSQL — When and Why

Document (Mongo), key-value (Redis, DynamoDB), wide-column (Cassandra), search (Elasticsearch). Pick by access pattern, not hype.

7. Web Fundamentals

core
HTTP

Methods, status codes, headers, caching, cookies, CORS. The layer everything web-shaped runs on.

REST, GraphQL, gRPC

When to use each. REST for public APIs, GraphQL for aggregating many backends, gRPC for internal service-to-service.

8. CI/CD & DevOps Basics

core
Docker & Containers

Every modern deploy is containerized. Learn images, layers, multi-stage builds, and image size hygiene.

GitHub Actions / CI Pipelines

Build, test, deploy on every push. Pipeline-as-code is the norm.

9. Security Fundamentals

recommended
OWASP Top 10

The vulnerabilities that ship in production every day. Read the list, understand each one, know how to prevent it in your stack.

AuthN vs AuthZ

Sessions, JWTs, OAuth2, OIDC, RBAC. The subject of ~30% of interview design questions.

10. Observability & Debugging

recommended
Logs, Metrics, Traces

The three pillars. Structured logs, RED/USE metrics, distributed tracing with OpenTelemetry.

Debugging in Production

Reproducing bugs from logs alone, reading heap dumps, using profilers. The skill that separates senior from mid.

11. Cloud Fundamentals

recommended
AWS Basics

EC2, S3, IAM, RDS, Lambda, VPC. The subset every backend engineer touches.

12. Career & Craft

optional
Writing Technical Design Docs

Every non-trivial change deserves a doc: problem, options, chosen approach, rollout plan.

The Staff / Principal Path

What it takes to get past Senior. Scope, impact, technical leadership without direct reports.

Take it further

Curated by WhatTNext Ai · methodology · all roadmaps · last updated 2026-07-29