Updated
A scheduled crawl and a URL monitor both fetch your pages the way a search engine does. They differ in how much of the site they cover, how often they run and what they send you afterwards.
Checks one live URL now: status, redirects, meta robots, X-Robots-Tag, canonical and robots.txt for Googlebot. Free, no signup.
Do you need a URL monitor if you already run scheduled crawls?
It depends on how fast you need to hear about a break on your most important pages. A scheduled crawl is the better tool for problems across the whole site: pages you didn't know about, broken internal links, duplicate titles, orphaned pages. If it runs daily and someone reads the results, it covers most of what a monitor does. A URL monitor fits when crawls run weekly or monthly, when nobody reviews the report, or when you want a message the day one of your key URLs changes, not a list of every issue.
How they compare
| Question | Scheduled crawl (Screaming Frog, site audit tools) | URL monitor (NoindexWatch) |
|---|---|---|
| Which URLs does it fetch? | Every URL it can reach from the start page or sitemap, up to your crawl limit | Only the URLs you choose: up to 20 per site |
| Finds problems on pages you didn't list? | Yes | No |
| Site-wide issues: duplicate titles, broken internal links, orphaned pages | Yes | No |
noindex in meta tags or X-Robots-Tag headers | Yes | Yes |
| robots.txt blocks | For the user agent the crawl uses | For Googlebot and Bingbot |
| Canonical pointing elsewhere, error status, redirect chains | Yes | Yes |
| URL dropped out of the XML sitemap | If you crawl the sitemap and compare it with the site | Per URL, at every check |
| AI crawlers blocked in robots.txt | Not as a standard report | Yes, for 14 AI crawlers |
| How often | As often as you schedule it | Daily on the free plan, hourly on paid plans |
| What you get | A full report every run | A message only when something changes, saying what changed |
| Load on your server | A full crawl every run | A few requests per URL per check |
When a scheduled crawl is the better choice
Run a crawl when you need to know what is wrong anywhere on the site, not only on pages you picked. A template change can put noindex on thousands of product pages; a monitor only sees it if one of its URLs uses that template. Crawls are also the right tool before and after a migration, for a first audit of a new client, and for issues no single page shows, such as internal links pointing to redirects or pages nothing links to.
Screaming Frog's SEO Spider is free for up to 500 URLs per crawl. Scheduled crawls need a paid licence, and since it is desktop software, they run on a computer you keep switched on. Hosted site audit tools, such as Semrush Site Audit, run on their own servers and let you set how often a project is recrawled, as part of a paid subscription.
When a URL monitor fits better
Crawls often run weekly or monthly, because a full crawl takes time and server load. A noindex that ships on Tuesday after Monday's crawl stays live until the next run, and Google may drop the page in the meantime.
A crawl also leaves the reading to you. Screaming Frog's scheduled crawls can email you when a crawl finishes, but its own guide notes that the email does not include the exports. Someone still has to open the report and spot what is new. A monitor compares each check with the last one and only writes when something on one of your URLs changed, for example /collections/boots, New: X-Robots-Tag header says "noindex", not the full list of known issues.
It also works without crawl access or software: it fetches the public URLs, so agencies can watch client sites and send alerts to a shared Slack or Discord channel.
Running both
Give the monitor one URL per template: the home page, a category, a product or article, and the landing pages that bring in leads or sales. That catches template-wide breaks the day they ship. Keep the crawl on its weekly or monthly schedule for depth. When the monitor alerts, run a crawl to see how many pages the change reached.
Watch your key templates every day
NoindexWatch checks the URLs you choose for noindex in meta tags and headers, robots.txt blocks, error status codes and redirect chains, canonicals that point elsewhere, URLs missing from the sitemap and AI crawler changes, and tells you by email, Slack or Discord when something changes. The free plan covers 1 site with up to 20 URLs, checked daily, no card.
Sources: Screaming Frog SEO Spider user guide (free version limit, licence, scheduling and notifications) and Semrush Knowledge Base on Site Audit scheduling. Related: What Search Console alerts on ยท Bulk indexability checker.