Bot signals · Web crawler
What is Oh Dear?
Oh Dear monitoring
Oh Dear is a website monitoring service. Its crawler visits sites its customers monitor to find broken links, mixed content and sitemap problems, and also checks that customers’ outgoing links to other sites still work.
01 · Profile
Oh Dear at a glance.
What to look for in your logs, and what the lookup API returns for its addresses.
- Type
- Web crawler
- User agent
OhDear.app- robots.txt
User-agent: OhDear- API flag
risk.is_crawler
A user agent alone never sets a flag. Anyone can claim to be Oh Dear; the flag follows the address the request comes from.
02 · In the response
What a match looks like.
A lookup of a Oh Dear address sets risk.is_crawler. The flags come with geolocation and network data in the same response, for API keys on every paid plan.
The response says which kind of bot an address belongs to, not which operator. A request that claims to be Oh Dear while risk.is_crawler is false should not be trusted as Oh Dear.
{
// … location and network fields …
"risk": {
"is_ai": false,
"is_crawler": true,
"is_scanner": false
}
}
03 · Control
Allow or block Oh Dear.
User-agent: OhDear Disallow: /
To enforce it
- robots.txt is a request. Well-behaved bots follow it; impostors using its name don’t.
- Firewall, WAF or CDN. Many offer bot rules you can allow or deny by category. Use them to enforce what robots.txt only asks for.
- In your app. Look up the client address and allow or deny on
risk.is_crawler, alongside the user agent. - Never on the user agent alone. Blocking the name stops only honest clients; allowing it lets anyone in who borrows it.
04 · Questions
About Oh Dear.
What is Oh Dear?
Oh Dear is a website monitoring service. Its crawler visits sites its customers monitor to find broken links, mixed content and sitemap problems, and also checks that customers’ outgoing links to other sites still work.
How do I block Oh Dear?
Add a robots.txt rule for OhDear. Oh Dear’s crawler follows robots.txt by default under the user agent OhDear. Its customers can switch this off in a monitor’s broken links or mixed content settings. To enforce a block rather than request one, deny it at your firewall, WAF or CDN.
Can I trust a request that says it is Oh Dear?
Not on the user agent alone: any client can send “OhDear.app” in its user agent. A user agent alone never sets a flag. Check the address with the free bot checker or the lookup API.
Which risk flag does Oh Dear set?
Its addresses set risk.is_crawler in the lookup response. The risk flags come with every paid plan.
From the blog
Go deeper.
Related bots
Recognise Oh Dear on every request.
is_ai, is_crawler and is_scanner in every lookup, on every paid plan, from 9,00 € a month (VAT included).