12 learning paths · 194 unique lessons
Choose the system you need to understand next.
Lessons may support more than one path. Completing a shared lesson counts everywhere it appears.
01 Design reliable backend systems through data, traffic, async work, and failure trade-offs.
Data and consistency · Database performance and operations · Production database query performance · Reliability and resilience · Async reliability · Production observability · Production resilience and overload control · Traffic and API architecture · Additional guided lessons
60 lessons → 02 Build production Spring services across request, transaction, data, security, operations, testing, and recovery boundaries.
Request and HTTP boundaries · Application and data boundaries · Security, operations, testing, and recovery
16 lessons → 03 Design message-driven systems across contracts, publication, consumption, ordering, recovery, and production operations.
Foundations and architectural decisions · Event contracts and reliable publication · Consumption, duplicates, ordering, and recovery · Coordination and production operations · Interactive failure lab
17 lessons → 04 Master shared-state correctness, task execution, cancellation, virtual threads, finite capacity, and production concurrency evidence.
Shared state and correctness · Task execution, composition, and cancellation · Virtual threads and structured tasks · Capacity and production operations · JVM performance, GC, and runtime diagnostics · Interactive concurrency lab
24 lessons → 05 Ship and operate backend services through immutable artifacts, Kubernetes workload boundaries, capacity, safe rollout, and verified recovery.
Container artifact and runtime boundaries · Kubernetes application boundaries · Capacity, availability, and scaling · Release and production operations · Capstone lab
15 lessons → 06 Operate Spring services through trustworthy telemetry, bounded signals, SLO alerting, incident command, and verified recovery.
Evidence foundations · Production signals · Telemetry delivery and reliability objectives · Incident operations · Capstone lab
18 lessons → 07 Operate PostgreSQL 18 and MySQL 8.4 InnoDB through transactions, concurrency, capacity, change, recovery, and incident evidence.
Engine and transaction boundaries · Concurrency and application correctness · Query and connection capacity · Change, replication, and recovery · Scale and incident operations · Capstone lab
17 lessons → 08 Choose Java collections by access pattern, correctness constraints, and performance behavior.
Map fundamentals · Equality and hashing · Set choices · List choices · Queues and priority · Complexity and performance
14 lessons → 09 Build clear API contracts that remain predictable through errors, retries, and change.
API style and contracts · Responses and errors · HTTP caching and delivery · Authentication and access · Reliability and retries · Data and integrations · Implementation and delivery
37 lessons → 10 Understand identity, tokens, sessions, OAuth, and browser security boundaries.
Authentication architecture · Token lifecycle and claims · Browser security risks · Protected API behavior
30 lessons → 11 Protect APIs, credentials, sessions, integrations, and operational trust boundaries.
Identity and access control · Token and session safety · Browser and cross-origin risks · Operational security · Secure API behavior
36 lessons → 12 Build practical complexity judgment for search, arrays, heaps, and backend code reviews.
Complexity fundamentals · Array and subarray patterns · Search and sorted data · Heaps and top K · Graph traversal · Probabilistic data structures · Java collection choices
18 lessons → 