diff --git a/nixos/modules/misc/ids.nix b/nixos/modules/misc/ids.nix
index 082b2732cc58..df071473f077 100644
--- a/nixos/modules/misc/ids.nix
+++ b/nixos/modules/misc/ids.nix
@@ -175,7 +175,7 @@
       dnsmasq = 141;
       uhub = 142;
       yandexdisk = 143;
-      #collectd = 144; #unused
+      mxisd = 144; # was once collectd
       consul = 145;
       mailpile = 146;
       redmine = 147;
@@ -483,7 +483,7 @@
       #dnsmasq = 141; # unused
       uhub = 142;
       #yandexdisk = 143; # unused
-      #collectd = 144; # unused
+      mxisd = 144; # was once collectd
       #consul = 145; # unused
       mailpile = 146;
       redmine = 147;
diff --git a/nixos/modules/module-list.nix b/nixos/modules/module-list.nix
index 2b7ee13ef71e..b97758ee6fb3 100644
--- a/nixos/modules/module-list.nix
+++ b/nixos/modules/module-list.nix
@@ -559,6 +559,7 @@
   ./services/networking/miredo.nix
   ./services/networking/mstpd.nix
   ./services/networking/murmur.nix
+  ./services/networking/mxisd.nix
   ./services/networking/namecoind.nix
   ./services/networking/nat.nix
   ./services/networking/ndppd.nix
diff --git a/nixos/modules/services/networking/mxisd.nix b/nixos/modules/services/networking/mxisd.nix
new file mode 100644
index 000000000000..0aa6d0d9ecd3
--- /dev/null
+++ b/nixos/modules/services/networking/mxisd.nix
@@ -0,0 +1,125 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.mxisd;
+
+  server = optionalAttrs (cfg.server.name != null) { inherit (cfg.server) name; }
+        // optionalAttrs (cfg.server.port != null) { inherit (cfg.server) port; };
+
+  baseConfig = {
+    matrix.domain = cfg.matrix.domain;
+    key.path = "${cfg.dataDir}/signing.key";
+    storage = {
+      provider.sqlite.database = "${cfg.dataDir}/mxisd.db";
+    };
+  } // optionalAttrs (server != {}) { inherit server; };
+
+  # merges baseConfig and extraConfig into a single file
+  fullConfig = recursiveUpdate baseConfig cfg.extraConfig;
+
+  configFile = pkgs.writeText "mxisd-config.yaml" (builtins.toJSON fullConfig);
+
+in {
+  options = {
+    services.mxisd = {
+      enable = mkEnableOption "mxisd matrix federated identity server";
+
+      package = mkOption {
+        type = types.package;
+        default = pkgs.mxisd;
+        defaultText = "pkgs.mxisd";
+        description = "The mxisd package to use";
+      };
+
+      dataDir = mkOption {
+        type = types.str;
+        default = "/var/lib/mxisd";
+        description = "Where data mxisd uses resides";
+      };
+
+      extraConfig = mkOption {
+        type = types.attrs;
+        default = {};
+        description = "Extra options merged into the mxisd configuration";
+      };
+
+      matrix = {
+
+        domain = mkOption {
+          type = types.str;
+          description = ''
+            the domain of the matrix homeserver
+          '';
+        };
+
+      };
+
+      server = {
+
+        name = mkOption {
+          type = types.nullOr types.str;
+          default = null;
+          description = ''
+            Public hostname of mxisd, if different from the Matrix domain.
+          '';
+        };
+
+        port = mkOption {
+          type = types.nullOr types.int;
+          default = null;
+          description = ''
+            HTTP port to listen on (unencrypted)
+          '';
+        };
+
+      };
+
+    };
+  };
+
+  config = mkIf cfg.enable {
+    users.users = [
+      {
+        name = "mxisd";
+        group = "mxisd";
+        home = cfg.dataDir;
+        createHome = true;
+        shell = "${pkgs.bash}/bin/bash";
+        uid = config.ids.uids.mxisd;
+      }
+    ];
+
+    users.groups = [
+      {
+        name = "mxisd";
+        gid = config.ids.gids.mxisd;
+      }
+    ];
+
+    systemd.services.mxisd = {
+      description = "a federated identity server for the matrix ecosystem";
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+
+      # mxisd / spring.boot needs the configuration to be named "application.yaml"
+      preStart = ''
+        config=${cfg.dataDir}/application.yaml
+        cp ${configFile} $config
+        chmod 444 $config
+      '';
+
+      serviceConfig = {
+        Type = "simple";
+        User = "mxisd";
+        Group = "mxisd";
+        ExecStart = "${cfg.package}/bin/mxisd --spring.config.location=${cfg.dataDir}/ --spring.profiles.active=systemd --java.security.egd=file:/dev/./urandom";
+        WorkingDirectory = cfg.dataDir;
+        PermissionsStartOnly = true;
+        SuccessExitStatus = 143;
+        Restart = "on-failure";
+      };
+    };
+  };
+}
diff --git a/nixos/tests/mxisd.nix b/nixos/tests/mxisd.nix
new file mode 100644
index 000000000000..3d03a5a53e38
--- /dev/null
+++ b/nixos/tests/mxisd.nix
@@ -0,0 +1,21 @@
+import ./make-test.nix ({ pkgs, ... } : {
+
+  name = "mxisd";
+  meta = with pkgs.stdenv.lib.maintainers; {
+    maintainers = [ mguentner ];
+  };
+
+  nodes = {
+    server_mxisd = args : {
+      services.mxisd.enable = true;
+      services.mxisd.matrix.domain = "example.org";
+    };
+  };
+
+  testScript = ''
+    startAll;
+    $server_mxisd->waitForUnit("mxisd.service");
+    $server_mxisd->waitForOpenPort(8090);
+    $server_mxisd->succeed("curl -Ssf \"http://127.0.0.1:8090/_matrix/identity/api/v1\"")
+  '';
+})