CatalogCanary

Most feed plugins generate a file and go quiet. When the feed breaks — products
silently vanish, required fields go missing, a run hangs and never finishes —
you find out weeks later when your ad performance craters.

CatalogCanary treats the feed as something to guard, not just generate:

• Meta catalog feed (CSV) regenerated hourly, built in batches so large
  catalogs never time out, and published atomically — Meta never fetches a
  half-written file.
• Change monitoring — every run is compared against the last one. If your
  product count drops by more than your chosen threshold (10% by default) and
  you didn’t remove those products, you get an email immediately.
• Required-field checking — products that would be rejected by Meta
  (missing price, image, description…) are reported to you with the exact
  missing fields, not silently dropped.
• Variable products done properly — every variation becomes its own catalog
  item with its own price, image and link, grouped by item_group_id, with
  colour/size/material/pattern mapped to Meta’s variant fields. If a variable
  product ends up with no variations in the feed, that’s called out
  separately — it means the whole product has vanished from your catalog, which
  is easy to miss among per-variation warnings.
• Stuck-run watchdog — a separate check catches runs that started and never
  finished, so a dying cron can’t take your feed down quietly.
• A quiet admin screen — no review nags, no upsell banners, no dashboard
  spam. An alert history table and a Run Now button.

Everything listed above is free, and nothing on this list is a trial or a
teaser. There is a paid version, CatalogCanary Pro, which adds change diffs
showing exactly which products left the feed and when, exclusion rules by
category, tag, stock state, price or SKU, and webhook alerts into Slack. It is
mentioned once, at the bottom of the plugin’s own settings page, and nowhere
else in your admin.