refetching

Refetching is the process of obtaining data again from a source after an initial fetch, in order to obtain a more current or accurate representation of the data. It is used across data-driven systems to ensure freshness, correctness, or to reflect user actions that modify data elsewhere.

In web and API contexts, refetching typically means issuing a new request to a server or to a cacheable data source. The response may be retrieved from a network, a local cache through revalidation, or a combination of both. HTTP mechanisms such as ETag or Last-Modified allow conditional requests, so refetching can validate whether the cached copy is still up to date. Cache-control directives influence how aggressively data is refetched, balancing freshness against bandwidth and latency.

Refetching is common in user interfaces. It can be user-initiated, such as pressing a refresh button, or automatic, such as polling at regular intervals or refocusing a tab after it becomes active again. Frontend libraries and data-fetching patterns often expose explicit refetch operations, sometimes with options to control revalidation behavior, polling frequency, or whether to refetch on focus or reconnect.

Trade-offs include increased latency and bandwidth usage versus data freshness, potential rate limiting, and the risk of flashing or inconsistencies if multiple sources update independently. Practical approaches combine caching with selective refetching, exponential backoff on failures, and user-focused refresh strategies to maintain responsiveness while avoiding unnecessary load.

See also: data caching, cache invalidation, revalidation, polling.