How to block BugsNag
Operated by Bugs Nag. BugsNag integration service, now Insight Hub, is used for error and performance monitoring of web applications.
How it identifies itself
Mozilla/5.0 (compatible; Bugsnag; +https://www.bugsnag.com/)
robots.txt
What the agent asks to be told. It obeys this or it does not — nothing enforces it.
User-agent: BugsNag Disallow: /
nginx
In the server block, then reload.
# In the server block. 403 rather than 444: a closed connection tells the # operator nothing, and an agent that gets a status code can log it. if ($http_user_agent ~* "(BugsNag|Bugsnag script fetcher ([email protected]))") { return 403; }
Apache
In .htaccess or the vhost.
BrowserMatchNoCase "BugsNag" bad_bot
BrowserMatchNoCase "Bugsnag script fetcher" bad_bot
<RequireAll>
Require all granted
Require not env bad_bot
</RequireAll>
Cloudflare
Security → WAF → Custom rules.
# Security → WAF → Custom rules, action: Block (http.user_agent contains "BugsNag") or (http.user_agent contains "Bugsnag script fetcher")
WordPress
A child theme's functions.php, or a small plugin.
// functions.php of a child theme, or a small plugin. Runs before WordPress
// builds the page, so a blocked agent costs one PHP process and no queries.
add_action('init', function () {
$agent = $_SERVER['HTTP_USER_AGENT'] ?? '';
foreach (['BugsNag', 'Bugsnag script fetcher'] as $needle) {
if (stripos($agent, $needle) !== false) {
status_header(403);
exit('Blocked: BugsNag');
}
}
});
robots.txt is a request. The rules below it are the wall.
BugsNag publishes a token, so the directive above will work for as long as it keeps honouring it — and nothing except its own good manners makes it. The server rules match on a header the requester sets, which stops the agent that says who it is and not the one that copies somebody else's name. Botscope verifies identity against DNS and published address ranges, records which check decided each request, and shows you the ones that lied.