A contract for reuse
Cache Index API
Design keys, freshness, invalidation, and observable misses as one coherent interface.
The idea, in context
A cache index API should explain how a caller identifies reusable work and how the system decides whether it remains valid. The record format is only part of the contract. A complete design covers access scope, source versions, expiration, invalidation, partial failure, and the fallback path. Start with a small interface whose states are easy to understand. The example record on this page is an illustrative blueprint for application design, not a live CacheIndex.com endpoint.
Describe states explicitly
Distinguish absent, expired, invalidated, unauthorized, and available entries in internal observability. A public interface may intentionally reveal less. Document which state triggers recomputation and which requires the caller to stop or refresh its authorization context.
Make writes complete and versioned
Publish a new index record only when the referenced value and metadata are ready. Use a version boundary or conditional update strategy appropriate to the storage system. Consider how concurrent workers avoid replacing a newer value with an older result.
Keep operations reviewable
Record why an entry was reused, rejected, refreshed, or removed without logging sensitive payloads unnecessarily. Test a model change, a source update, a permissions change, and an expired entry. These cases reveal whether the interface expresses the actual reuse policy.
Questions about cache index api
Can I call an endpoint from this page?
The page is a design reference and example contract. It does not expose an operational API or issue credentials.
Should the API use HTTP caching as well?
Possibly, but that is a separate layer. If responses themselves are cacheable, define their HTTP policy in addition to the application-level cache record.
Start with one good question.
Follow a topic, explore the tradeoffs, and go deeper in the Lab.