poll‑server‑check is an npm library that lets front‑end applications continuously monitor a backend’s availability. It provides a `clientCheck` function that pings a given URL, automatically retries when the server is down, and shows toast notifications of the current status, while the complementary `serverCheck` helper adds a simple health‑check endpoint to an Express app. It’s aimed at developers building web apps—especially React projects—who want an out‑of‑the‑box way to keep users informed when their API service is temporarily unavailable.