Perl
Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages.
What detecting Perl tells you about a site
Perl is one of the web's oldest server languages and today usually signals a long-lived, mature system rather than a new build. You detect it from `Server` headers naming mod_perl or a Plack/PSGI stack, `.pl`/`.cgi` URL patterns, or Catalyst/Mojolicious framework signatures. Finding it tells you you are likely looking at infrastructure with years of history — sysadmin tooling, bioinformatics, established back-office systems — where the cost of rewriting outweighs the appeal of a newer language.
Perl in a real-world stack
When you find Perl, it rarely travels alone. mod_perl under Apache, or a Plack/PSGI server; Catalyst or Mojolicious where a framework is used.
About
Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages.
Categories: Programming languages
Quick facts
Detection methodology for Programming languages
Programming languages reveal themselves through extension fingerprints (`.php` URLs for PHP, `.aspx` for ASP.NET), framework-specific patterns and (for client-side runtime languages like TypeScript and Sass) the `node_modules/<lang>/package.json` entry inside the sourcemap. Bun, Node.js and Deno on the server side identify themselves via response headers when emitted (`X-Powered-By: Bun`, `X-Bun-Version`).
How we detect Perl
Sourcemap Explorer carries 2 fingerprint signals for Perl, spread across 2 channels — response header and dom selector. The exact patterns are listed below, and you can replay each one in Chrome DevTools to confirm a match by hand.
Each signal alone is rarely conclusive — Sourcemap Explorer cross-references all of them and weights by confidence. You can reproduce any of these checks yourself in Chrome DevTools.
Server-side fingerprint: the response header reveals the technology behind the page. Visible in DevTools → Network → response headers.
Server: \bPerl\b(?: ?/?v?([\d.]+))?
A DOM selector that only this technology's pages render. Verified at runtime by the content script.
form[action*='/discus/search.pl']
FAQ
How do I check if a website is using Perl?
Open the page in Chrome, click the Sourcemap Explorer toolbar icon, and read the Stack tab. Perl's specific fingerprints here are response header and dom selector, and the popup flags Perl whenever any combination of them is found. The same checks can be reproduced manually in DevTools — see the "How we detect" section above.
What Perl version can Sourcemap Explorer detect?
Perl ships as a hosted programming languages rather than a bundled npm package, so version-specific detection isn't always possible. Where the platform leaks a version in response headers (`X-Powered-By`, `Server`, generator meta tags) we surface it; otherwise we report presence only.
Where can I read more about Perl?
Official site: https://perl.org. For Sourcemap Explorer's detection guide, see the deep-dive link below or the related guides in the cross-link section.
Keep reading on Sourcemap Explorer
Practical guides
Alternative tools
Detected by Sourcemap Explorer
Open the popup on any page running Perland you'll see the exact version pulled from the bundled package.json when sourcemaps are exposed.