Developer Community Warns Against Third-Party LLM API Proxies Faking Prompt Caching

On November 5, 2026, the AI section of the DEV Community published an article titled "Beware of third-party LLM API proxies faking Claude Prompt Caching." Its author says the piece came out of building upstream routing for a multi-model gateway, during which more than a dozen third-party relay services were audited. Many of them claim to support prompt caching, but either break it through flawed architecture or forge telemetry data to make it appear to work, so the benefits are never actually delivered. The article groups the failures into four common traps, walks through the break-even math that shows when caching even pays off, and ships a test script so developers can check their own providers. The piece notes that anyone running Claude Code or Cline every day should have caching, since Anthropic bills 1.25x the base price to write a cache checkpoint and 0.1x to read it, a combination that can cut costs by up to 90% on large contexts. The text begins to detail the first trap, naive key-pooling, before the available excerpt ends. No response from the implicated providers or Anthropic is quoted, so the matter currently rests on the author's findings and the offered testing tooling.