diff --git a/flake.lock b/flake.lock
index 7788dc72..75182d65 100644
--- a/flake.lock
+++ b/flake.lock
@@ -1,5 +1,21 @@
 {
   "nodes": {
+    "MediaWikiExtensionsComposer": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1710203136,
+        "narHash": "sha256-yn4ZzzaYTZu46SvgctwtiISwC7rzda+1PwvaX6Zxq58=",
+        "ref": "refs/heads/master",
+        "rev": "f4489ac8400b1570d49204ff27b958f49c554007",
+        "revCount": 1,
+        "type": "git",
+        "url": "https://gitea.c3d2.de/c3d2/MediaWikiExtensionsComposer.git"
+      },
+      "original": {
+        "type": "git",
+        "url": "https://gitea.c3d2.de/c3d2/MediaWikiExtensionsComposer.git"
+      }
+    },
     "affection-src": {
       "inputs": {
         "flake-utils": [
@@ -487,6 +503,7 @@
     },
     "root": {
       "inputs": {
+        "MediaWikiExtensionsComposer": "MediaWikiExtensionsComposer",
         "affection-src": "affection-src",
         "alert2muc": "alert2muc",
         "bevy-julia": "bevy-julia",
diff --git a/flake.nix b/flake.nix
index 98ed0c94..143df53c 100644
--- a/flake.nix
+++ b/flake.nix
@@ -93,7 +93,11 @@
         utils.follows = "flake-utils";
       };
     };
-    # hydra-ca.url = "github:mlabs-haskell/hydra/aciceri/ca-derivations";
+    # extra repository to not infalte this repository's size
+    MediaWikiExtensionsComposer = {
+      url = "git+https://gitea.c3d2.de/c3d2/MediaWikiExtensionsComposer.git";
+      flake = false;
+    };
     microvm = {
       url = "github:astro/microvm.nix";
       inputs = {
@@ -215,7 +219,7 @@
     };
   };
 
-  outputs = inputs@{ self, alert2muc, c3d2-user-module, deployment, disko, fenix, heliwatch, microvm, naersk, nixos, nixos-hardware, nixos-modules, buzzrelay, caveman, oparl-scraper, scrapers, secrets, skyflake, sshlogd, sops-nix, spacemsg, ticker, tigger, yammat, zentralwerk, ... }:
+  outputs = inputs@{ self, alert2muc, c3d2-user-module, deployment, disko, fenix, heliwatch, MediaWikiExtensionsComposer, microvm, naersk, nixos, nixos-hardware, nixos-modules, buzzrelay, caveman, oparl-scraper, scrapers, secrets, skyflake, sshlogd, sops-nix, spacemsg, ticker, tigger, yammat, zentralwerk, ... }:
     let
       inherit (nixos) lib;
 
@@ -475,6 +479,9 @@
           modules = [
             self.nixosModules.microvm
             ./hosts/mediawiki
+            {
+              _module.args = { inherit MediaWikiExtensionsComposer; };
+            }
           ];
         };
 
diff --git a/hosts/mediawiki/default.nix b/hosts/mediawiki/default.nix
index d2e5996c..a77b393c 100644
--- a/hosts/mediawiki/default.nix
+++ b/hosts/mediawiki/default.nix
@@ -1,4 +1,4 @@
-{ config, lib, libC, pkgs, ... }:
+{ config, lib, libC, MediaWikiExtensionsComposer, pkgs, ... }:
 
 let
   cfg = config.services.mediawiki;
@@ -69,6 +69,33 @@ in
           url = "https://web.archive.org/web/20230710142618/https://extdist.wmflabs.org/dist/extensions/PluggableAuth-REL1_40-519c6d2.tar.gz";
           sha256 = "sha256-N1+OV1UdzvU4iXhaS/+fuEoAXqrkVyyEPDirk0vrT8A=";
         };
+        # source https://github.com/Die-KoMa/mediawiki/blob/main/packages/default.nix#L32-L47
+        # TODO: generalize
+        SemanticMediaWiki = let
+          drv = import MediaWikiExtensionsComposer {
+            noDev = true;
+            inherit pkgs;
+            php = pkgs.php81;
+            phpPackages = pkgs.php81Packages;
+          };
+        in
+          pkgs.stdenv.mkDerivation {
+            name = "mediawiki-extensions-composer";
+            dontUnpack = true;
+
+            installPhase = ''
+              mkdir $out
+              cp -R ${drv}/extensions/SemanticMediaWiki/* $out
+              cp -R ${drv}/vendor vendor
+
+              pushd vendor/composer/
+              substituteInPlace *.json *.php \
+                --replace "/extensions/SemanticMediaWiki" ""
+              popd
+
+              cp -R vendor $out/
+            '';
+          };
       };
 
       name = "C3D2";
@@ -157,9 +184,9 @@ in
 
         wfLoadExtension('ConfirmEdit/QuestyCaptcha');
         $wgCaptchaClass = 'QuestyCaptcha';
-        $wgCaptchaQuestions[] = array( 'question' => 'How is C3D2 logo in ascii?', 'answer' => '<<</>>' );
+        $wgCaptchaQuestions[] = array('question' => 'How is C3D2 logo in ascii?', 'answer' => '<<</>>');
 
-        wfLoadExtension( 'Interwiki' );
+        wfLoadExtension('Interwiki');
         $wgGroupPermissions['sysop']['interwiki'] = true;
 
         wfLoadExtension('Cite');
@@ -178,6 +205,20 @@ in
         # LDAP
         $LDAPProviderDomainConfigs = "${config.sops.secrets."mediawiki/ldapprovider".path}";
         $wgPluggableAuth_EnableLocalLogin = true;
+
+        # SemanticMediaWiki
+        # TODO: expose https://github.com/NixOS/nixpkgs/blob/nixos-unstable/nixos/modules/services/web-apps/mediawiki.nix#L19
+        $smwgConfigFileDir = "/var/lib/mediawiki";
+        # default was 100 which is already occupied, using 200 to 215
+        # https://www.semantic-mediawiki.org/wiki/Help:$smwgNamespaceIndex
+        $smwgNamespaceIndex = 200;
+        # Doesn't work? Not sure why....
+        # enableSemantics('${config.services.mediawiki.nginx.hostName}');
+        # $smwgURITypeSchemeList = array_merge(
+        #   $smwgURITypeSchemeList, [
+        #     'xmpp', 'mumble', 'ssh'
+        #   ]
+        # );
       '';
     };
 
@@ -187,7 +228,7 @@ in
         # for some reason nginx adds a port for the 301 redirect from / to /wiki/
         port_in_redirect off;
       '';
-      virtualHosts."wiki.c3d2.de" = {
+      virtualHosts."${config.services.mediawiki.nginx.hostName}" = {
         enableACME = true;
         forceSSL = true;
         listen = libC.defaultListen;