About our crawler

If you found TechnoUnion-HeaderWalker in your server logs, this page explains what it is and how to stop it.

What it is

Allsource operates a crawler that identifies which technology products a company's website uses. It requests the home page of a domain, reads the HTTP response headers and the returned HTML, and records the names of technology vendors it recognises. It identifies itself with this User-Agent:

TechnoUnion-HeaderWalker/1.1 (+https://www.allsourcedata.io/crawler; honors opt-out; headers-only)

What it requests

A domain is visited no more than once every 30 days. Requests are made from 15.204.104.113.

What it records

The names of technology vendors detected on the site, and the account identifier a tag carries when one is present in the public page source. The page content itself is discarded after it is read and is not stored, republished, or used to reproduce the site.

The crawler does not collect personal information about visitors to your site. It does not execute JavaScript, set cookies, or interact with any analytics or advertising tag on the page.

How to block it

The fastest way is robots.txt, which takes effect on the next visit and requires nothing from us. Add this to the robots.txt file at the root of your domain:

User-agent: TechnoUnion-HeaderWalker
Disallow: /

A wildcard rule blocking all crawlers also works, because this crawler applies the User-agent: * group when no rule names it specifically.

Removal by request

If you cannot edit robots.txt, or you want a domain on a permanent do-not-crawl list that does not depend on that file, email crawler@optout.allsourcedata.io with the domain or domains you want excluded.

Requests are processed automatically within about ten minutes, and you will get a confirmation once it is done. Domains on that list are never requested again, regardless of what robots.txt says, and any records we already hold for them are deleted.

If it is causing a problem

The crawler makes two requests to a domain once a month, so it is unlikely to affect a site's performance. If you are seeing something different from that, email the address above with a sample of your access log and we will look at it.

This page describes the crawler operated by AllSource Data Corporation. It is separate from the global opt-out, which covers individual consumer records rather than websites.