diff --git a/flake.lock b/flake.lock
index 57575c2..8675ef3 100644
--- a/flake.lock
+++ b/flake.lock
@@ -1,23 +1,64 @@
 {
   "nodes": {
+    "lowdown-src": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1617481909,
+        "narHash": "sha256-SqnfOFuLuVRRNeVJr1yeEPJue/qWoCp5N6o5Kr///p4=",
+        "owner": "kristapsdz",
+        "repo": "lowdown",
+        "rev": "148f9b2f586c41b7e36e73009db43ea68c7a1a4d",
+        "type": "github"
+      },
+      "original": {
+        "owner": "kristapsdz",
+        "ref": "VERSION_0_8_4",
+        "repo": "lowdown",
+        "type": "github"
+      }
+    },
+    "nix": {
+      "inputs": {
+        "lowdown-src": "lowdown-src",
+        "nixpkgs": "nixpkgs"
+      },
+      "locked": {
+        "lastModified": 1627638914,
+        "narHash": "sha256-KnMQRMDqidemayib7HUTSbKuxFaLxHUEf9bGq+ajVzo=",
+        "owner": "nixos",
+        "repo": "nix",
+        "rev": "c15e121e322ee5bca1d96d59cc0b693e5bd9d0bf",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "ca/queryRealisation-perl",
+        "repo": "nix",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1606086654,
-        "narHash": "sha256-VFl+3eGIMqNp7cyOMJ6TjM/+UcsLKtodKoYexrlTJMI=",
+        "lastModified": 1624862269,
+        "narHash": "sha256-JFcsh2+7QtfKdJFoPibLFPLgIW6Ycnv8Bts9a7RYme0=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "19db3e5ea2777daa874563b5986288151f502e27",
+        "rev": "f77036342e2b690c61c97202bf48f2ce13acc022",
         "type": "github"
       },
       "original": {
         "id": "nixpkgs",
-        "ref": "nixos-20.09",
+        "ref": "nixos-21.05-small",
         "type": "indirect"
       }
     },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs"
+        "nix": "nix",
+        "nixpkgs": [
+          "nix",
+          "nixpkgs"
+        ]
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index 3f9828a..2b9f431 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,7 +1,8 @@
 {
-  inputs.nixpkgs.url = "nixpkgs/nixos-20.09";
+  inputs.nixpkgs.follows = "nix/nixpkgs";
+  inputs.nix.url = "github:nixos/nix/ca/queryRealisation-perl";
 
-  outputs = { self, nixpkgs }:
+  outputs = { self, nixpkgs, nix }:
 
     let
       forAllSystems = f: nixpkgs.lib.genAttrs systems (system: f system);
@@ -13,7 +14,7 @@
         nix-serve = with final; stdenv.mkDerivation {
           name = "nix-serve-${self.lastModifiedDate}";
 
-          buildInputs = [ perl nix.perl-bindings perlPackages.Plack perlPackages.Starman perlPackages.DBDSQLite ];
+          buildInputs = [ perl nix.defaultPackage.${super.system}.passthru.perl-bindings perlPackages.Plack perlPackages.Starman perlPackages.DBDSQLite ];
 
           unpackPhase = "true";
 
diff --git a/nix-serve.psgi b/nix-serve.psgi
index dfa5b38..aca520d 100644
--- a/nix-serve.psgi
+++ b/nix-serve.psgi
@@ -15,7 +15,14 @@ my $app = sub {
     my $path = $env->{PATH_INFO};
 
     if ($path eq "/nix-cache-info") {
-        return [200, ['Content-Type' => 'text/plain'], ["StoreDir: $Nix::Config::storeDir\nWantMassQuery: 1\nPriority: 30\n"]];
+        return [200, ['Content-Type' => 'text/plain'], ["StoreDir: /nix/store\nWantMassQuery: 1\nPriority: 30\n"]];
+    }
+
+    elsif ($path =~ /^\/realisations\/(.*)\.doi/) {
+        my $rawDrvOutput = $1;
+        my $rawRealisation = queryRawRealisation($rawDrvOutput);
+        return [404, ['Content-Type' => 'text/plain'], ["No such derivation output.\n"]] unless $rawRealisation;
+        return [200, ['Content-Type' => 'text/plain'], [$rawRealisation]];
     }
 
     elsif ($path =~ /^\/([0-9a-z]+)\.narinfo$/) {