Learning Paths
Ordered tracks that combine courses, decision guides, coding practice and quizzes. Sign in to track your progress along a path.
Coding Interview Prep
Pattern-by-pattern algorithm practice, the most-asked problems, practical backend tasks and language gotchas — with code you run in the browser.
Backend Engineer Foundations
The core every backend engineer needs regardless of stack: HTTP APIs, auth, caching, retries, queues and observability.
API Architect
Design, govern and evolve API platforms: REST, GraphQL, contracts, versioning, gateways, security and developer experience.
Reliability Engineer
Keep systems correct and available under retries, overload and partial failure.
Event-Driven & Distributed Systems
Queues, streams, event sourcing, real-time delivery and the distributed-systems theory behind them.
Mobile Backend Engineer
Build APIs that survive flaky networks, old app versions and battery limits.
API Security
Authentication, authorization, the OWASP Top 10 for web and APIs, abuse protection and secure delivery.
AI-Integrated Products
Ship features on top of LLM APIs safely: streaming, structured outputs, cost control, evaluation and abuse limits.
Payments & Fintech Engineer
Move money correctly: idempotent charges, payment state machines, webhooks, ledgers, reconciliation and security.
Data at Scale Engineer
Concurrency, transactions, database scaling and caching for high-traffic, resilient systems — with runnable simulations and practice tasks.
Engineering Leadership: Tech Lead to Engineering Manager
From senior engineer to tech lead, team lead and engineering (development) manager — technical direction, running a team, hiring, performance and organisation design, with interview prep for each role.
Design Patterns: From SOLID to Real Refactoring
Learn to design code that is easy to change: SOLID and dependency injection, all 23 classic patterns, the modern patterns frameworks use, when not to use a pattern, then practise with code reviews, a quiz and interview questions.
Data Engineer: Reliable Pipelines from Source to Warehouse
Build pipelines people can trust: extraction and change data capture, idempotent loading, late data and backfills, dimensional modelling, dbt and orchestration, data quality, cost and privacy, plus the messaging and idempotency foundations underneath.