Edge or in-memory cache

Updated 10:42

Should the product feed use an edge cache or an in-memory cache? Show me a typed example.

10:41

Short answer: cache at the edge for 60 seconds and revalidate in the background. Here is how the two options compare.

Strategy	Best for	Trade-off
Edge cache	Many regions, read-heavy pages	Stale for up to the TTL
In-memory	One region, low traffic	Cold after every deploy
Both	Mixed traffic	Two places to invalidate

A typed version of the loader:

TypeScript

type Feed = { items: { id: string; title: string }[]; updatedAt: number };
export async function readFeed(load: () => Promise<Feed>, ttl = 60_000) {
  const cached = cache.get("feed");
  if (cached && Date.now() - cached.updatedAt < ttl) return cached;
  const fresh = await load();
  cache.set("feed", fresh);
  return fresh;
}

Before you ship it:

Key the cache by locale, not just by path.
Set a stale-while-revalidate window so readers never wait on a refresh.
Log the hit rate for a week, then tune the TTL.

Good. Purge the feed cache in every region so the correction goes out.

10:44

I need your approval before I run this. It clears the cached feed in three regions, and the next request in each one will be slow while it refills.

Input

{
  "key": "feed",
  "regions": [
    "eu",
    "us",
    "apac"
  ],
  "reason": "Editor published a correction"
}

This tool wants to run. Review the input, then allow or deny it.

AI can make mistakes. Check important info.