diff --git a/flake.nix b/flake.nix
index 97034da..d05475b 100644
--- a/flake.nix
+++ b/flake.nix
@@ -269,6 +269,7 @@
           promnesia = pkgs.python3Packages.callPackage ./pkgs/promnesia.nix {
             inherit pkgs;
           };
+          sliding-sync = pkgs.callPackage ./pkgs/sliding-sync.nix { inherit pkgs; };
           tailscaleSystray =
             pkgs.callPackage ./pkgs/tailscale-systray.nix { inherit pkgs; };
           golink = pkgs.callPackage ./pkgs/golink.nix { inherit pkgs; };
diff --git a/pkgs/sliding-sync.nix b/pkgs/sliding-sync.nix
new file mode 100644
index 0000000..ee13bb4
--- /dev/null
+++ b/pkgs/sliding-sync.nix
@@ -0,0 +1,25 @@
+{ lib, buildGoModule, fetchFromGitHub, ... }:
+with lib;
+buildGoModule rec {
+  pname = "sliding-sync";
+  version = "0.99.1";
+
+  src = fetchFromGitHub {
+    owner = "matrix-org";
+    repo = pname;
+    rev = "v${version}";
+    hash = "sha256-g1yMGb8taToEFG6N057yPcdZB855r0f6EwnJ98FIiic=";
+  };
+
+  vendorHash = "sha256-FmibAVjKeJUrMSlhoE7onLoa4EVjQvjDI4oU4PB5LBE=";
+
+  # Note: tests require a postgres install accessible to the current user
+  doCheck = false;
+
+  meta = {
+    description = "An implementation of MSC3575";
+    homepage = "https://github.com/matrix-org/sliding-sync";
+    license = licenses.asl20;
+    maintainers = with maintainers; [ qbit ];
+  };
+}