Distributed Tracing in 2026 — OpenTelemetry, Trace Context, and What Actually Helps Debugging
Practical distributed tracing: OTEL setup, span design, context propagation across services, head/tail sampling, and the operational realities.
Backend
Circuit Breakers in 2026 — Patterns, Pitfalls, and When They Save You
Practical circuit breakers: the closed/open/half-open state machine, threshold tuning, fallback strategies, libraries (resilience4j, py-breaker), and where breakers go wrong.
Event Sourcing in 2026 — When It's Worth the Complexity
Practical event sourcing: append-only streams, projections, snapshots, replay, and an honest take on when ES pays off vs when CRUD wins.
gRPC vs REST vs GraphQL in 2026 — Pick the Right Tool, Not the Loudest One
Practical API protocol selection: REST for simplicity and HTTP cache, gRPC for service-to-service perf, GraphQL for client-driven queries — and the gotchas of each.
Django + Celery in 2026 — Background Jobs Without the Footguns
Production Django + Celery: task signatures, idempotency, retry strategies, beat scheduling, monitoring, and how to avoid the lost-job class of bugs.
Axum Middleware in 2026 — Tower, Layers, and Production Patterns
Practical Axum middleware: auth, request ID, tracing, rate limiting, error mapping, and how Tower’s layer composition actually works.
API Gateway Patterns in 2026 — Kong, Envoy, Cloudflare, and the Hybrids
Picking an API gateway. Kong, Envoy, Cloudflare Workers as gateway, Tyk, and the patterns from real platforms — auth, rate limiting, transformations, observability.
API Rate Limit Design — Quotas, Headers, and 429 Patterns in 2026
Designing customer-facing API rate limits. Tier structure, quota types (per-second / per-minute / per-day), Stripe / GitHub-style response headers, 429 with Retry-After, and the patterns customers actually integrate with.
Serialization Formats in 2026 — Protobuf, MessagePack, CBOR, FlatBuffers
Comparison of binary serialization formats. Protobuf for typed RPC. MessagePack / CBOR as JSON drop-ins. FlatBuffers when zero-copy matters. JSON when humans must read.
Zero-Downtime Database Migrations in 2026 — The Expand-and-Contract Playbook
The full expand-and-contract migration playbook. Add a column, rename a column, drop a column, change a type — each as a multi-step deploy that never blocks.