Why AI gateways became standard infrastructure in 2026. The OpenAI-compatible façade pattern, LiteLLM vs Portkey vs Helicone vs OpenRouter, fallbacks, caching, observability, cost control, and how to drop one in front of an existing app.
How OpenTelemetry actually works in 2026. The collector, traces / metrics / logs / context propagation, instrumenting Python, Go, and Rust services, sampling that doesn’t kill recall, and the production-grade end-to-end setup.
A short, practical guide to SLOs and error budgets for application developers. Choose the right SLI, pick targets you can actually defend, calculate the budget, and use it to drive feature-velocity vs. reliability tradeoffs.
How to make a backend observable: structured logs, RED/USE metrics, distributed traces, and the tooling (Prometheus, Loki, OpenTelemetry, Grafana) that ties it together.