diff --git a/modules/services/matrix.nix b/modules/services/matrix.nix
index bd78a79..d47b74f 100644
--- a/modules/services/matrix.nix
+++ b/modules/services/matrix.nix
@@ -41,6 +41,10 @@ in
         owner = "matrix-synapse";
         group = "matrix-synapse";
       };
+
+      "matrix/matrix.hillion.co.uk/syncv3_secret" = {
+        file = ../../secrets/matrix/matrix.hillion.co.uk/syncv3_secret.age;
+      };
     };
 
     services = {
@@ -114,6 +118,15 @@ in
         };
       };
 
+      matrix-synapse.sliding-sync = {
+        enable = true;
+        environmentFile = config.age.secrets."matrix/matrix.hillion.co.uk/syncv3_secret".path;
+        settings = {
+          SYNCV3_SERVER = "https://matrix.hillion.co.uk";
+          SYNCV3_BINDADDR = "[::]:8009";
+        };
+      };
+
       heisenbridge = lib.mkIf cfg.heisenbridge {
         enable = true;
         owner = "@jake:hillion.co.uk";
diff --git a/modules/www/global.nix b/modules/www/global.nix
index a3aee28..38befff 100644
--- a/modules/www/global.nix
+++ b/modules/www/global.nix
@@ -42,7 +42,10 @@ in
             header /.well-known/matrix/* Access-Control-Allow-Origin *
 
             respond /.well-known/matrix/server "{\"m.server\": \"matrix.hillion.co.uk:443\"}" 200
-            respond /.well-known/matrix/client `{"m.homeserver":{"base_url":"https://matrix.hillion.co.uk"}}`
+            respond /.well-known/matrix/client `${builtins.toJSON {
+              "m.homeserver" = { "base_url" = "https://matrix.hillion.co.uk"; };
+              "org.matrix.msc3575.proxy" = { "url" = "https://matrix.hillion.co.uk"; };
+            }}` 200
 
             respond 404
           }
@@ -65,6 +68,7 @@ in
           reverse_proxy http://${locations.services.gitea}:3000
         '';
         "matrix.hillion.co.uk".extraConfig = ''
+          reverse_proxy /_matrix/client/unstable/org.matrix.msc3575/sync http://${locations.services.matrix}:8009
           reverse_proxy /_matrix/* http://${locations.services.matrix}:8008
           reverse_proxy /_synapse/client/* http://${locations.services.matrix}:8008
         '';
diff --git a/secrets/matrix/matrix.hillion.co.uk/syncv3_secret.age b/secrets/matrix/matrix.hillion.co.uk/syncv3_secret.age
new file mode 100644
index 0000000..71bec00
--- /dev/null
+++ b/secrets/matrix/matrix.hillion.co.uk/syncv3_secret.age
@@ -0,0 +1,20 @@
+age-encryption.org/v1
+-> ssh-rsa GxPFJQ
+Z3WKcEusrn04hb2zUpEFBHOoqDIaCzMo/jZuOX/eMKPBqTrxcba9ZgxOFE7+yaUi
+FJvlQNg5pQn/vaCtHkJWfBXdKiwZ3pIeaqwNcto8EprKLxIAkLjMBMOursz9k41E
+0B4NKRyxiQO2kMgjKb9jYzhioan3NG1Loto8RbjbUPlqn/Q0NEsq8Uql0qaM02Ba
+zBd1Xt1MFDtemXxzfmeqLMX45F67B8JKFujnXajR7qoRCmzz6kkj6zb+SEE+Nodq
+9J/i4rpgwP0B9Zgp9QqnvOBVuLtxPOv/EE+Dp9Ktj1v5SxlJbQoPBiX5pZd5n3/n
+dqibdn1Jls57qCs9sHAlDQ
+-> ssh-rsa K9mW1w
+BMNOK5nTDPSw5wZsdWlpWzbA62WdDmqg3CdiYSA8mDZT5LFHsmZt4azfwvCWnwKh
+jvzWsNgASSdCCGk4xzDR8qzVAvcku5IxgQjGWCfa307r8k1RFMF910+QpS0nsckE
+voBCvNIbv1Qjg6MKSXIDmmDjeLedL/0WYp7mX2FHQbs2Mau3xHz+l4mW9C6Dlyeu
+PdR6IYJxqxDOqQk2FIMYq7vS1JWDo2ntS3XcufUL4V6TeFj1Soauff9/55hqt8Tm
+JlUkbHmc/69bsqbr3en1sk6lk7GV7M87tfjGJuhdsMQLY10jFuZfkpewRhCLTEpR
+LFooblAploXTZfXkvmoj2A
+-> ssh-ed25519 iWiFbA izGiArlZgQMVSnQv/WG7+tBUnk0z/iUHI1TgAf0d5V0
+Qw/pUd8y7UNElE9U+VwE7cQhemfPXFhFoiKQya34Bwo
+--- FfPFhjvH78/oBzE1tL93Vxm6fV9zsHL3S8aDb3KWA4o
+óœ}þŠlj¿mE_¿9mç}z ¼?ü
-Ø9F•]IóãÞØy7uw¼x¼ŠQ3ÅìüqñŠJ„åVº–/”º@>°vÊî-G4;Êí1Ñ&@§k®
ÍWë+c*ûžìá|#»û˜Èª­³Wy
+fC°
\ No newline at end of file
diff --git a/secrets/secrets.nix b/secrets/secrets.nix
index 4ec4773..e1bc100 100644
--- a/secrets/secrets.nix
+++ b/secrets/secrets.nix
@@ -72,6 +72,8 @@ in
   "matrix/matrix.hillion.co.uk/email.age".publicKeys = jake_users ++ [ ts.cx.boron ];
   "matrix/matrix.hillion.co.uk/registration_shared_secret.age".publicKeys = jake_users ++ [ ts.cx.boron ];
 
+  "matrix/matrix.hillion.co.uk/syncv3_secret.age".publicKeys = jake_users ++ [ ts.cx.boron ];
+
   # Backups Secrets
   "restic/128G.age".publicKeys = jake_users ++ [ ts.storage.tywin ts.cx.boron ts.home.microserver ];
   "restic/1.6T.age".publicKeys = jake_users ++ [ ts.storage.tywin ts.home.router ];