Reliability & Security

Keeping a system up and safe: resilience, observability, SLOs, disaster recovery, threat modelling, authentication and incident response. 2 modules, about 3 hours of reading. Every lesson ends in something to do.

Reliability

Resilience PatternsTimeouts, retries, backoff, circuit breakers and bulkheads — how to call a dependency that will eventually fail without failing with it.Intermediate18 min
Observability: Logs, Metrics & TracesThe three signals, what each one costs, and why cardinality — not storage — is the constraint that decides your design.Intermediate20 min
Monitoring & Alerting: SLOs and Error BudgetsWhat to measure, how error budgets turn reliability into a trade-off, and why burn-rate alerts beat static thresholds.Intermediate19 min
Multi-Region & Disaster RecoveryWhy you go multi-region, active-passive versus active-active, RPO and RTO, cross-region writes, and why failover is the part that fails.Advanced21 min

Security

Security Basics (HTTPS, SSL, TLS)What TLS actually guarantees, how the handshake works, certificates and the mistakes that silently disable it.Intermediate17 min
Threat ModellingHow to work out what can go wrong before you build it, instead of collecting defences and hoping they were the right ones.Intermediate16 min
Authentication: Session vs JWT vs OAuthHow each mechanism actually works, the revocation problem, refresh tokens and where to store them.Intermediate17 min
Application SecurityInjection, XSS, CSRF, SSRF, broken object-level authorisation and mass assignment — what attackers do to your application and the structural fixes.Intermediate22 min
Advanced Security (OAuth & Zero Trust)The OAuth 2.0 flows in detail, why PKCE exists, and what zero trust actually changes in an architecture.Advanced17 min
Detection and Incident ResponseEvery other control assumes prevention works. This one assumes it did not — how you notice, and what you do in the first hour.Intermediate17 min