Crowkis vs Anthropic prompt caching: cache writes that bill you are telling you something
Anthropic's prompt caching is excellent at its actual job — cheap long contexts. It was never designed to be your response cache, and the pricing says so.
Anthropic's prompt caching shines for what it was built for: agents and chat apps re-sending a large stable context get the repeated prefix at a steep discount, with cache writes billed at a premium and entries expiring in minutes. Take that deal for your long system prompts — we do. But read the design closely and it tells you its scope: short-lived, prefix-exact, input-side, single-provider.
Five-minute TTLs mean your cache evaporates between user sessions. Prefix-exactness means paraphrased questions never qualify. Input-side means the answer — the expensive part — is regenerated every time. And provider-side means your accumulated cache value is a feature of someone else's pricing page, revocable and non-portable.
Four doors in, one cache, and the model only sees genuinely new questions.
Crowkis is the durable, output-side complement: answers persist on your disk for as long as your TTL policy says, match by meaning rather than prefix, survive restarts and model swaps, and serve in under a millisecond without touching the API at all. Your cache becomes an asset you own rather than a discount you receive.
The bottom line
The composition is clean: Anthropic's caching cuts the cost of calls Crowkis decides must happen; Crowkis eliminates the rest. One optimizes the pipe, the other installs a reservoir.