diff --git a/hosts/carcosa/configuration.nix b/hosts/carcosa/configuration.nix
index 823a6dac..abd41fbf 100644
--- a/hosts/carcosa/configuration.nix
+++ b/hosts/carcosa/configuration.nix
@@ -424,25 +424,9 @@ in
   nixfiles.bookdb.remoteSync.receive.authorizedKeys =
     [ "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIChVw9DPLafA3lCLCI4Df9rYuxedFQTXAwDOOHUfZ0Ac remote-sync@nyarlathotep" ];
 
-  users.extraUsers.nyarlathotep-remote-sync = {
-    home = "/var/lib/nyarlathotep-remote-sync";
-    createHome = true;
-    isSystemUser = true;
-    openssh.authorizedKeys.keys =
-      [ "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIChVw9DPLafA3lCLCI4Df9rYuxedFQTXAwDOOHUfZ0Ac remote-sync@nyarlathotep" ];
-    shell = pkgs.bashInteractive;
-    group = "nogroup";
-    packages =
-      let
-        bookmarks-receive-elasticsearch = ''
-          env ES_HOST=${config.systemd.services.bookmarks.environment.ES_HOST} \
-              ${pkgs.nixfiles.bookmarks}/bin/bookmarks_ctl import-index --drop-existing
-        '';
-      in
-      [
-        (pkgs.writeShellScriptBin "bookmarks-receive-elasticsearch" bookmarks-receive-elasticsearch)
-      ];
-  };
+  nixfiles.bookmarks.remoteSync.receive.enable = true;
+  nixfiles.bookmarks.remoteSync.receive.authorizedKeys =
+    [ "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIChVw9DPLafA3lCLCI4Df9rYuxedFQTXAwDOOHUfZ0Ac remote-sync@nyarlathotep" ];
 
   ###############################################################################
   ## Miscellaneous
diff --git a/hosts/nyarlathotep/configuration.nix b/hosts/nyarlathotep/configuration.nix
index 93fd8940..203e4d01 100644
--- a/hosts/nyarlathotep/configuration.nix
+++ b/hosts/nyarlathotep/configuration.nix
@@ -495,37 +495,9 @@ in
   nixfiles.bookdb.remoteSync.send.sshKeyFile = config.sops.secrets."users/remote_sync/ssh_private_key".path;
   nixfiles.bookdb.remoteSync.send.targets = [ "carcosa.barrucadu.co.uk" ];
 
-  users.extraUsers.remote-sync = {
-    home = "/var/lib/remote-sync";
-    createHome = true;
-    isSystemUser = true;
-    shell = pkgs.bashInteractive;
-    group = "nogroup";
-  };
-
-  systemd.services.bookmarks-sync = {
-    description = "Upload bookmarks data to carcosa";
-    startAt = "*:15";
-    path = with pkgs; [ openssh ];
-    serviceConfig = {
-      ExecStart = pkgs.writeShellScript "bookmarks-sync" ''
-        set -ex
-
-        env "ES_HOST=$ES_HOST" \
-            ${pkgs.nixfiles.bookmarks}/bin/bookmarks_ctl export-index | \
-        ssh -i "$SSH_KEY_FILE" \
-            -o UserKnownHostsFile=/dev/null \
-            -o StrictHostKeyChecking=no \
-            nyarlathotep-remote-sync@carcosa.barrucadu.co.uk \
-            bookmarks-receive-elasticsearch
-      '';
-      User = config.users.extraUsers.remote-sync.name;
-    };
-    environment = {
-      ES_HOST = config.systemd.services.bookmarks.environment.ES_HOST;
-      SSH_KEY_FILE = config.sops.secrets."users/remote_sync/ssh_private_key".path;
-    };
-  };
+  nixfiles.bookmarks.remoteSync.send.enable = true;
+  nixfiles.bookmarks.remoteSync.send.sshKeyFile = config.sops.secrets."users/remote_sync/ssh_private_key".path;
+  nixfiles.bookmarks.remoteSync.send.targets = [ "carcosa.barrucadu.co.uk" ];
 
   sops.secrets."users/remote_sync/ssh_private_key".owner = config.users.extraUsers.remote-sync.name;
 
diff --git a/shared/bookmarks/default.nix b/shared/bookmarks/default.nix
index e09d8bae..af39ef5a 100644
--- a/shared/bookmarks/default.nix
+++ b/shared/bookmarks/default.nix
@@ -17,6 +17,8 @@ in
 {
   imports = [
     ./options.nix
+    ./remote-sync-receive.nix
+    ./remote-sync-send.nix
   ];
 
   config = mkIf cfg.enable {
diff --git a/shared/bookmarks/options.nix b/shared/bookmarks/options.nix
index 796e3911..1582deb7 100644
--- a/shared/bookmarks/options.nix
+++ b/shared/bookmarks/options.nix
@@ -60,5 +60,47 @@ with lib;
         Format of the log messages.
       '';
     };
+
+    remoteSync = {
+      receive = {
+        enable = mkOption {
+          type = types.bool;
+          default = false;
+          description = mdDoc ''
+            Enable receiving push-based remote sync from other hosts.
+          '';
+        };
+        authorizedKeys = mkOption {
+          type = types.listOf types.str;
+          default = [ ];
+          description = mdDoc ''
+            SSH public keys to allow pushes from.
+          '';
+        };
+      };
+
+      send = {
+        enable = mkOption {
+          type = types.bool;
+          default = false;
+          description = mdDoc ''
+            Enable periodically pushing local state to other hosts.
+          '';
+        };
+        sshKeyFile = mkOption {
+          type = types.str;
+          description = mdDoc ''
+            Path to SSH private key.
+          '';
+        };
+        targets = mkOption {
+          type = types.listOf types.str;
+          default = [ ];
+          description = mdDoc ''
+            Hosts to push to.
+          '';
+        };
+      };
+    };
   };
 }
diff --git a/shared/bookmarks/remote-sync-receive.nix b/shared/bookmarks/remote-sync-receive.nix
new file mode 100644
index 00000000..4752f555
--- /dev/null
+++ b/shared/bookmarks/remote-sync-receive.nix
@@ -0,0 +1,29 @@
+# see remote-sync-send.nix
+{ config, lib, pkgs, ... }:
+
+with lib;
+let
+  cfg = config.nixfiles.bookmarks.remoteSync.receive;
+in
+{
+  config = mkIf cfg.enable {
+    users.extraUsers.bookmarks-remote-sync-receive = {
+      home = "/var/lib/bookmarks-remote-sync-receive";
+      createHome = true;
+      isSystemUser = true;
+      openssh.authorizedKeys.keys = cfg.authorizedKeys;
+      shell = pkgs.bashInteractive;
+      group = "nogroup";
+      packages =
+        let
+          receive-elasticsearch = ''
+            env ES_HOST=${config.systemd.services.bookmarks.environment.ES_HOST} \
+                ${pkgs.nixfiles.bookmarks}/bin/bookmarks_ctl import-index --drop-existing
+          '';
+        in
+        [
+          (pkgs.writeShellScriptBin "receive-elasticsearch" bookmarks-receive-elasticsearch)
+        ];
+    };
+  };
+}
diff --git a/shared/bookmarks/remote-sync-send.nix b/shared/bookmarks/remote-sync-send.nix
new file mode 100644
index 00000000..63e1d7fd
--- /dev/null
+++ b/shared/bookmarks/remote-sync-send.nix
@@ -0,0 +1,47 @@
+# see remote-sync-receive.nix
+{ config, lib, pkgs, ... }:
+
+with lib;
+let
+  cfg = config.nixfiles.bookmarks.remoteSync.send;
+
+  toService = target: {
+    name = "bookmarks-sync-${target}";
+    value = {
+      description = "Upload bookmarks data to ${target}";
+      startAt = "*:15";
+      path = with pkgs; [ openssh ];
+      serviceConfig = {
+        ExecStart = pkgs.writeShellScript "bookmarks-sync" ''
+          set -ex
+
+          env "ES_HOST=$ES_HOST" \
+              ${pkgs.nixfiles.bookmarks}/bin/bookmarks_ctl export-index | \
+          ssh -i "$SSH_KEY_FILE" \
+              -o UserKnownHostsFile=/dev/null \
+              -o StrictHostKeyChecking=no \
+              bookmarks-remote-sync-receive@${target} \
+              receive-elasticsearch
+        '';
+        User = config.users.extraUsers.bookmarks-remote-sync-send.name;
+      };
+      environment = {
+        ES_HOST = config.systemd.services.bookmarks.environment.ES_HOST;
+        SSH_KEY_FILE = cfg.sshKeyFile;
+      };
+    };
+  };
+in
+{
+  config = mkIf cfg.enable {
+    users.extraUsers.bookmarks-remote-sync-send = {
+      home = "/var/lib/bookmarks-remote-sync-send";
+      createHome = true;
+      isSystemUser = true;
+      shell = pkgs.bashInteractive;
+      group = "nogroup";
+    };
+
+    systemd.services = listToAttrs (map toService cfg.targets);
+  };
+}