diff --git a/flake.lock b/flake.lock
index 9d686f6..69b8601 100644
--- a/flake.lock
+++ b/flake.lock
@@ -1,12 +1,145 @@
 {
   "nodes": {
+    "checker": {
+      "inputs": {
+        "clj-nix": "clj-nix",
+        "nixpkgs": "nixpkgs"
+      },
+      "locked": {
+        "lastModified": 1776095659,
+        "narHash": "sha256-3xXKVCwzjNKjctilYZWXcejxeE+9FPVLZaVuciFQmAI=",
+        "ref": "refs/heads/main",
+        "rev": "57fe47b20e85ab3b8eba87a1a24d5ae46f1beaa7",
+        "revCount": 32,
+        "type": "git",
+        "url": "https://codeberg.org/oibot/checker.git"
+      },
+      "original": {
+        "type": "git",
+        "url": "https://codeberg.org/oibot/checker.git"
+      }
+    },
+    "clj-nix": {
+      "inputs": {
+        "devshell": "devshell",
+        "nix-fetcher-data": "nix-fetcher-data",
+        "nixpkgs": [
+          "checker",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1773151887,
+        "narHash": "sha256-YUiehwe2iTlwYSrnJ1pcw7KDNX+U42xlTx/2k/mo0P8=",
+        "owner": "jlesquembre",
+        "repo": "clj-nix",
+        "rev": "27dac4466c9d3939f6a4925bc09e0cb1d8f32d9c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "jlesquembre",
+        "repo": "clj-nix",
+        "type": "github"
+      }
+    },
+    "devshell": {
+      "inputs": {
+        "nixpkgs": [
+          "checker",
+          "clj-nix",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1768818222,
+        "narHash": "sha256-460jc0+CZfyaO8+w8JNtlClB2n4ui1RbHfPTLkpwhU8=",
+        "owner": "numtide",
+        "repo": "devshell",
+        "rev": "255a2b1725a20d060f566e4755dbf571bbbb5f76",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "devshell",
+        "type": "github"
+      }
+    },
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": "nixpkgs-lib"
+      },
+      "locked": {
+        "lastModified": 1719745305,
+        "narHash": "sha256-xwgjVUpqSviudEkpQnioeez1Uo2wzrsMaJKJClh+Bls=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "c3c5ecc05edc7dafba779c6c1a61cd08ac6583e9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
+    "nix-fetcher-data": {
+      "inputs": {
+        "flake-parts": "flake-parts",
+        "nixpkgs": [
+          "checker",
+          "clj-nix",
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1755022803,
+        "narHash": "sha256-/QtBdVfZlrRJW5enUoWlBE2wrLXJBMJ45X0rZh0jiaU=",
+        "owner": "jlesquembre",
+        "repo": "nix-fetcher-data",
+        "rev": "9da3926b1459d6ff15268072d1c51351b82811b9",
+        "type": "github"
+      },
+      "original": {
+        "owner": "jlesquembre",
+        "repo": "nix-fetcher-data",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1770136044,
-        "narHash": "sha256-tlFqNG/uzz2++aAmn4v8J0vAkV3z7XngeIIB3rM3650=",
+        "lastModified": 1775811116,
+        "narHash": "sha256-t+HZK42pB6N+i5RGbuy7Xluez/VvWbembBdvzsc23Ss=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "e576e3c9cf9bad747afcddd9e34f51d18c855b4e",
+        "rev": "54170c54449ea4d6725efd30d719c5e505f1c10e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "nixos-25.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "nixpkgs-lib": {
+      "locked": {
+        "lastModified": 1717284937,
+        "narHash": "sha256-lIbdfCsf8LMFloheeE6N31+BMIeixqyQWbSr2vk79EQ=",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs/archive/eb9ceca17df2ea50a250b6b27f7bf6ab0186f198.tar.gz"
+      },
+      "original": {
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs/archive/eb9ceca17df2ea50a250b6b27f7bf6ab0186f198.tar.gz"
+      }
+    },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1775811116,
+        "narHash": "sha256-t+HZK42pB6N+i5RGbuy7Xluez/VvWbembBdvzsc23Ss=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "54170c54449ea4d6725efd30d719c5e505f1c10e",
         "type": "github"
       },
       "original": {
@@ -18,7 +151,8 @@
     },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs",
+        "checker": "checker",
+        "nixpkgs": "nixpkgs_2",
         "sops-nix": "sops-nix"
       }
     },
@@ -29,11 +163,11 @@
         ]
       },
       "locked": {
-        "lastModified": 1775682595,
-        "narHash": "sha256-0E9PohY/VuESLq0LR4doaH7hTag513sDDW5n5qmHd1Q=",
+        "lastModified": 1775971308,
+        "narHash": "sha256-VKp9bhVSm0bT6JWctFy06ocqxGGnWHi1NfoE90IgIcY=",
         "owner": "Mic92",
         "repo": "sops-nix",
-        "rev": "d2e8438d5886e92bc5e7c40c035ab6cae0c41f76",
+        "rev": "31ac5fe5d015f76b54058c69fcaebb66a55871a4",
         "type": "github"
       },
       "original": {
diff --git a/flake.nix b/flake.nix
index 446f875..dc292a1 100644
--- a/flake.nix
+++ b/flake.nix
@@ -3,14 +3,20 @@
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.11";
     sops-nix.url = "github:Mic92/sops-nix";
     sops-nix.inputs.nixpkgs.follows = "nixpkgs";
+    checker.url = "git+https://codeberg.org/oibot/checker.git";
   };
 
-  outputs = { self, nixpkgs, sops-nix, ... }:
+  outputs = { self, nixpkgs, sops-nix, checker, ... }:
     let
       system = "x86_64-linux";
     in {
       nixosConfigurations.tobserver = nixpkgs.lib.nixosSystem {
         inherit system;
+
+        specialArgs = {
+          inherit checker;
+        };
+
         modules = [
           sops-nix.nixosModules.sops
           ./hardware-configuration.nix
@@ -20,6 +26,7 @@
           ./modules/mempool.nix
           ./modules/nextcloud.nix
           ./modules/totap.nix
+          ./modules/checker.nix
         ];
       };
     };
diff --git a/modules/checker.nix b/modules/checker.nix
new file mode 100644
index 0000000..d0f5b33
--- /dev/null
+++ b/modules/checker.nix
@@ -0,0 +1,53 @@
+{ config, pkgs, checker, ... }:
+
+let
+  checkerPkg = checker.packages.${pkgs.stdenv.hostPlatform.system}.default;
+in
+{
+  users.users.checker = {
+    isSystemUser = true;
+    group = "checker";
+    home = "/var/lib/checker";
+    createHome = true;
+  };
+
+  users.groups.checker = {};
+
+  sops.secrets."checker/env" = {
+    owner = "checker";
+    group = "checker";
+    mode = "0400";
+  };
+
+  systemd.services.checker = {
+    description = "Checker a personal assistant";
+    wantedBy = [ "multi-user.target" ];
+    after = [ "network.target" ];
+
+    serviceConfig = {
+      User = "checker";
+      Group = "checker";
+      WorkingDirectory = "/var/lib/checker";
+      ExecStart = "${checkerPkg}/bin/checker";
+      EnvironmentFile = config.sops.secrets."checker/env".path;
+
+      Restart = "always";
+      RestartSec = 5;
+
+      NowNewPrivileges = true;
+      PrivateTmp = true;
+      ProtectSystem = "strict";
+      ProtectHome = true;
+      ReadWritePaths = [ "/var/lib/checker" ];
+    };
+  };
+
+  services.nginx.virtualHosts."checker.tobiasostner.de" = {
+    enableACME = true;
+    forceSSL = true;
+
+    locations."/" = {
+      proxyPass = "http://127.0.0.1:3001";
+    };
+  };
+}
diff --git a/secrets/tobserver.yaml b/secrets/tobserver.yaml
index ebc1005..63255c1 100644
--- a/secrets/tobserver.yaml
+++ b/secrets/tobserver.yaml
@@ -3,6 +3,8 @@ mempool:
     mariadb-root-password: ENC[AES256_GCM,data:CjXQWw==,iv:3amyq9/3Nq7pz8s7wk4UORI1gSgURufGh1u/cITQf/I=,tag:4ulBVRDh0Ws04IqHT5P6tg==,type:str]
 nextcloud:
     admin-pass: ENC[AES256_GCM,data:3xufFHvcm5g5+jn+B4qxRljuWDqDXo1mLu4IlSuax7Cz+3ZoOuNXoCXoiaY=,iv:WaWeu/a45Vuz+HvO7m0dUlCGCexk4IX/ijURmb/7jPU=,tag:ytRjS89AmHiGOhKymViTrg==,type:str]
+checker:
+    env: ENC[AES256_GCM,data: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,iv:NOc6iW2JaHse+52AQJNkY1jqFk6GAIyHf9wITvsKPPM=,tag:GKF/MjBU364lr7lG4vrwnA==,type:str]
 sops:
     age:
         - recipient: age1qnudtkywppsdk6zn6jh9gra093w4mnf63m333hxsms9ys7elkpps3y008z
@@ -23,7 +25,7 @@ sops:
             cVE5VG56cFAzT1dsRFN4cCtnVEJJdU0KSBWm4blGhnVlOJ3k7lh8aJVOEH8NfFOh
             EwU/4Up6zWYBoe2+GKiQf8imnVLSSxMR7dlNd06ttuFD4B5baqFRcA==
             -----END AGE ENCRYPTED FILE-----
-    lastmodified: "2026-04-11T17:27:25Z"
-    mac: ENC[AES256_GCM,data:0926uedsIZ1GyhtTJjedMPds3zGvANUlRH6ro0abt391OfJ+b1z/pgjT7bRxiJNCOZITKfkaWoXR0529PK00dZAI2Z70lX2oDftNEtBzX+cq994m0s3HlfjaChqRwpFfxxX7sYbyvGqQRJxxgbiMfloyNeps55ODKXGXYwNKYog=,iv:PRHplnL6SUBwx1+wpi8uvWKZvHurhdiexIJr0kjQ8ao=,tag:uwDy9B7uP0khPorbc2woRA==,type:str]
+    lastmodified: "2026-04-13T16:18:47Z"
+    mac: ENC[AES256_GCM,data:En7+/DW4k5KkoyEXYIH8xZyBv8cRjzYQgIVA8PzfRx1YhquEnfS538kU3i79iKJrQHucmr8PtCO7oPCwrus5xzTeRmn6iVIcTzAqJigyd3Nf4yjgE24isay79jZGq62q05YTaYbQpVfQCoCUK5U/S1AJXte/l5dSYQL614K1eQ0=,iv:Tlp7BBJr/Nu3SAVIPofSTuDx5PSr84mUaOT9fLJN/Jw=,tag:lQLO7tzm3VAP2pPxKo5uWw==,type:str]
     unencrypted_suffix: _unencrypted
     version: 3.11.0