2.Microservices & Platform

Identity layer on OAuth with ID tokens, UserInfo, issuer/audience/nonce validation, and authentication sessions.

Signed token format, claims, validation, expiration, key management, and common security misconceptions.

Delegated authorization with resource owner, client, authorization server, resource server, scopes, access tokens, and secure redirect flows.

Versioned configuration distribution with environments, validation, watches, rollout, caching, security, and rollback.

Endpoint discovery, selection algorithms, health/outlier detection, connection reuse, locality, weighting, and overload-aware routing.

Service membership registration, discovery, leases/health, staleness, replication, client caches, and failure handling.

Gateway routing and cross-cutting policy with authentication, limits, deadlines, observability, resilience, and safe ownership boundaries.

Metrics, logs, traces, events, SLOs, correlation, storage, alerting, dashboards, and cost/cardinality control.

Trace/span context propagation, sampling, storage, causality, asynchronous work, and correlation with metrics/logs.

Timeouts, deadlines, retries, circuit breakers, bulkheads, rate limits, load shedding, fallbacks, and idempotency.

Structured logs, severity, correlation, context, sampling, retention, privacy, and operational querying.

Metric naming/types, labels, cardinality control, RED/USE signals, SLOs, aggregation, and alerting.

Identity proof, sessions/tokens, authorization policy, least privilege, service identity, revocation, and audit.