A practical curriculum for backend developers
194 focused lessons connect Spring, Java, API design, authentication, security, algorithms, and system design—then turn the ideas into deliberate practice.
Your learning plan
Choose a course, follow the lessons in order, and check your understanding as you go.
The knowledge atlas
Follow a full course or enter through the problem you are solving today. Shared lessons count across every relevant path.
Design reliable backend systems through data, traffic, async work, and failure trade-offs.
Build production Spring services across request, transaction, data, security, operations, testing, and recovery boundaries.
Design message-driven systems across contracts, publication, consumption, ordering, recovery, and production operations.
Master shared-state correctness, task execution, cancellation, virtual threads, finite capacity, and production concurrency evidence.
Ship and operate backend services through immutable artifacts, Kubernetes workload boundaries, capacity, safe rollout, and verified recovery.
Operate Spring services through trustworthy telemetry, bounded signals, SLO alerting, incident command, and verified recovery.
Operate PostgreSQL 18 and MySQL 8.4 InnoDB through transactions, concurrency, capacity, change, recovery, and incident evidence.
Choose Java collections by access pattern, correctness constraints, and performance behavior.
Build clear API contracts that remain predictable through errors, retries, and change.
Understand identity, tokens, sessions, OAuth, and browser security boundaries.
Protect APIs, credentials, sessions, integrations, and operational trust boundaries.
Build practical complexity judgment for search, arrays, heaps, and backend code reviews.
Continue exploring
Reliability Labs Aug 19, 2026 3 min read
Use six deterministic browser scenarios to reason about pools, locks, retries, replica lag, failover interruption, and evidence boundaries.
Observability Aug 19, 2026 3 min read
Correlate demand, pools, sessions, transactions, locks, plans, storage, logs, and replicas without leaking sensitive database data.
Databases Aug 19, 2026 3 min read
Interpret estimates, runtime plans, statistics, parameters, and index choices using each engine's documented evidence boundaries.
Local-first workbench
Format, inspect, compare, and transform backend data without sending inputs to a server.
Available tool
Encode text to Base64 and decode Base64 back to readable text locally in your browser.
Open toolAvailable tool
Look up common Big-O complexities for Java collections, algorithms, and backend patterns with a fast browser-based reference table.
Open toolAvailable tool
Explain standard five-field cron expressions and preview upcoming run times locally in your browser.
Open tool