Bot signals · Web crawler
What is Marginalia Search crawler?
The Marginalia Search crawler collects pages for Marginalia Search, an open-source search engine. It revisits sites in a full crawl every 8 to 10 weeks and checks RSS updates daily in between, and Marginalia says its goal is a well-behaved crawler.
01 · Profile
Marginalia Search crawler at a glance.
What to look for in your logs, and what the lookup API returns for its addresses.
- Type
- Web crawler
- User agent
search.marginalia.nu- robots.txt
User-agent: search.marginalia.nu- API flag
risk.is_crawler
A user agent alone never sets a flag. Anyone can claim to be Marginalia Search crawler; the flag follows the address the request comes from.
02 · In the response
What a match looks like.
A lookup of a Marginalia Search crawler 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 Marginalia Search crawler while risk.is_crawler is false should not be trusted as Marginalia Search crawler.
{
// … location and network fields …
"risk": {
"is_ai": false,
"is_crawler": true,
"is_scanner": false
}
}
03 · Control
Allow or block Marginalia Search crawler.
User-agent: search.marginalia.nu 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 Marginalia Search crawler.
What is Marginalia Search crawler?
The Marginalia Search crawler collects pages for Marginalia Search, an open-source search engine. It revisits sites in a full crawl every 8 to 10 weeks and checks RSS updates daily in between, and Marginalia says its goal is a well-behaved crawler.
How do I block Marginalia Search crawler?
Add a robots.txt rule for search.marginalia.nu. Marginalia Search gives search.marginalia.nu as its crawler’s robots.txt identifier. 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 Marginalia Search crawler?
Not on the user agent alone: any client can send “search.marginalia.nu” 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 Marginalia Search crawler 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 Marginalia Search crawler on every request.
is_ai, is_crawler and is_scanner in every lookup, on every paid plan, from 9,00 € a month (VAT included).