Streaming makes responses feel fast, but it creates a hard recovery boundary. Learn when an LLM request can fail over safely, why emitted tokens cannot be replayed silently, and how clients should handle partial output.
Request count and dollar cost tell different stories, and the gap between them is where the savings are. Here are the four shapes an overlay of cost and usage produces, which one to chase first, and what makes the numbers trustworthy enough to act on.
Configure log destinations once at the gateway instead of instrumenting every call site. Here is how to add and verify a callback today, what the Beta does and does not deliver yet, and the live paths that get data out in the meantime.
"Redact the logs and you cannot debug" is a false trade. Here is how write-time redaction, typed structure-preserving placeholders and metadata scrubbing keep LLM request logs reproducible while the sensitive values never reach durable storage.
The fields that make an LLM request log worth keeping, the content that turns it into a liability, and how a gateway's built-in logs compare with running your own self-hosted trace store.
An average latency number describes an experience nobody had. Here is how to read LLM latency as a distribution — p50, p95, p99, time-to-first-token and total completion time — and how to find what is actually causing a bad tail.
"The AI bill went up" becomes a query once spend carries structure. Three attribution layers — virtual keys, teams, and the OpenAI-spec user field — turn one opaque total into a breakdown you can group, filter, and cap.
Head-to-head: nRouter vs Langfuse. A self-hostable observability + prompt + evals specialist vs a hosted LLM gateway that bundles observability, routing, and governance — every feature included on every plan. Pay-as-you-go fee of 4% of your credits, 0% on Pro. Models available in your live catalog behind one API key.
One user action becomes fifty model calls across four agent roles. Here is how to attribute that spend by role, by run and by step, reconcile it against the ledger, and put a ceiling under it that application code cannot bypass.
