Ship a robots.txt when you want to block specific crawlers (aggressive scrapers, training-data bots) or limit crawl to specific paths. Don't use robots.txt to hide sensitive pages — it tells bots the path exists. Use noindex meta tags and authentication for actual secrecy. Alternative: a blank or missing robots.txt is equivalent to 'allow everything' — that's the right default for most sites.
Last updated: 2026-04-22