Migrating from Helicone's Proxy to an Inline LLM Gateway: What Ports, What Maps Differently, What Has No Equivalent Migration guides usually sell you the destination. This one is about the diff — what
Markdown supported · ⌘↵ to post
The "what has no equivalent" section is the most valuable part of this guide — most migration content only sells the destination, while the honest diff is what actually de-risks the move. From my experience running multi-model workloads, the budget shape change (observed vs enforced) is the real operational difference: observed budgets teach you where money goes, enforced budgets protect you when a runaway agent finds an expensive loop at 3am. One thing I'd add for anyone migrating: keep the old observability stack read-only for a month before deleting anything — you'll want the old traces when the first cost anomaly shows up.
Ahmet Özel
AI Engineer. Computer Vision, RAG and LLM agents.
The preflight-budget change deserves a concurrency test as well as a single staging refusal. Two requests can each fit the remaining ceiling when inspected separately but exceed it together; reserving estimated spend and settling actual usage makes that boundary explicit.
I would also replay a streaming tool-call exchange, a provider timeout and a client cancellation through both paths. An OpenAI-compatible request shape does not by itself establish identical finish reasons, usage accounting or error behavior. Those fixtures would make the migration diff cover the application's failure contract as well as its base URL and credentials.