Symfony
Symfony is a PHP web application framework and a set of reusable PHP components/libraries.
What detecting Symfony tells you about a site
Symfony is the enterprise-grade PHP framework whose components also underpin much of the PHP ecosystem (including parts of Laravel and Drupal). Its server tells are a symfony or PHPSESSID-style session cookie, the unmistakable interactive debug toolbar and the X-Debug-Token/X-Debug-Token-Link headers in non-production, and /bundles/ asset paths. Spotting it points to a structured, long-lived PHP application built by a team that valued architectural rigour and decoupled components — typically agencies, larger businesses and complex back-office systems.
Symfony in a real-world stack
When you find Symfony, it rarely travels alone. PHP-FPM with Doctrine ORM over MySQL/PostgreSQL, Twig for templating, and Webpack Encore or Vite for assets.
About
Symfony is a PHP web application framework and a set of reusable PHP components/libraries.
Categories: Web frameworks
Quick facts
How we detect Symfony
Sourcemap Explorer carries 4 fingerprint signals for Symfony, spread across 4 channels — cookie, javascript global, script src url 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.
Cookies set by the platform. Visible in DevTools → Application → Cookies.
sf_redirect
Window-level global the technology installs on page. Reproducible by typing the path into the DevTools console.
window.Sfjs
Script URL pattern. Typically a CDN host or chunk path that ships with the technology.
/@?symfony/
A DOM selector that only this technology's pages render. Verified at runtime by the content script.
div.sf-toolbar-block, div.sf-toolbar
Implies
When Symfonyis detected, Sourcemap Explorer also marks the following technologies as present (Wappalyzer's implies graph).
FAQ
How do I check if a website is using Symfony?
Open the page in Chrome, click the Sourcemap Explorer toolbar icon, and read the Stack tab. Symfony's specific fingerprints here are cookie, javascript global, script src url and dom selector, and the popup flags Symfony whenever any combination of them is found. The same checks can be reproduced manually in DevTools — see the "How we detect" section above.
What Symfony version can Sourcemap Explorer detect?
Symfony ships as a hosted web frameworks 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.
Is Symfony open source?
Yes, Symfony is open source. The license details are listed on the official site (https://symfony.com), and the codebase typically lives on a public source-control host.
Where can I read more about Symfony?
Official site: https://symfony.com. For Sourcemap Explorer's detection guide, see the deep-dive link below or the related guides in the cross-link section.
Detected by Sourcemap Explorer
Open the popup on any page running Symfonyand you'll see the exact version pulled from the bundled package.json when sourcemaps are exposed.