Yes, if the checker sends site: queries to the Custom Search JSON API. Google retires that API on January 1, 2027; it is already closed to new customers, and the partner-only successor has no published pricing or quota. After the cutoff the script will return auth errors, not empty results, so an unattended monitor stops silently.
Check this first
- Search the code for
customsearch/v1 or a cx= parameter — that is the affected call.
- Look at Google Cloud billing for a "Custom Search API" line; if it is there, something is still using it.
- Note the daily volume: the old cap was 10,000 queries/day at $5 per 1,000 after 100 free.
- Confirm the checker only needs an indexed / not-indexed verdict, not titles or positions.
If it still fails
- Replace the per-URL loop with a bulk call: the SpeedyIndex checker API takes up to 10,000 URLs per task and returns
indexed_links and unindexed_links.
- Split the nightly job into submit and collect; processing is asynchronous.
- Run both checkers on a few hundred URLs and reconcile disagreements in Search Console before switching off the old path.
Related: Google Custom Search API Shutdown — FAQ for SEO Teams
Background on what the shutdown changes for index checking: full breakdown. Google's own notice: Custom Search JSON API overview.