diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..a5dbbcb
--- /dev/null
+++ b/.envrc
@@ -0,0 +1 @@
+use flake .
diff --git a/default.nix b/default.nix
deleted file mode 100644
index 8e98f99..0000000
--- a/default.nix
+++ /dev/null
@@ -1,10 +0,0 @@
-let
-  pkgs = import <nixpkgs> {};
-in pkgs.mkShell {
-  packages = [
-    (pkgs.python3.withPackages (python-pkgs: [
-      python-pkgs.python-telegram-bot
-    ]))
-  ];
-}
-
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..6abb3e2
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,61 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1709126324,
+        "narHash": "sha256-q6EQdSeUZOG26WelxqkmR7kArjgWCdw5sfJVHPH/7j8=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "d465f4819400de7c8d874d50b982301f28a84605",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1709101946,
+        "narHash": "sha256-TsySgcWm/GlbYdL3AEva49ceeI2BdPQ7muwfYNr1fwo=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "d53c2037394da6fe98decca417fc8fda64bf2443",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..a3bacbd
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,27 @@
+{
+  description = "Python3 telegram bot environment";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = { self, nixpkgs, flake-utils, ... }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs {
+          inherit system;
+        };
+        pythonEnv = pkgs.python3.withPackages (ps: with ps; [
+          python-telegram-bot
+        ]);
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          buildInputs = with pkgs; [
+            pythonEnv
+          ];
+        };
+      });
+}
+
diff --git a/seshsecretary.py b/seshsecretary.py
index bd42b97..d8f3af2 100755
--- a/seshsecretary.py
+++ b/seshsecretary.py
@@ -1,6 +1,6 @@
 #!/usr/bin/python
 
-from telegram.ext import Updater, CommandHandler, Filters
+from telegram.ext import Updater, CommandHandler, filters
 import os
 from random import randrange
 import sys
@@ -93,7 +93,7 @@ def main():
     updater.dispatcher.add_handler(CommandHandler("list", _list))
     updater.dispatcher.add_handler(CommandHandler("get", get))
     updater.dispatcher.add_handler(CommandHandler("random", random))
-    updater.dispatcher.add_handler(CommandHandler("save", save, Filters.reply))
+    updater.dispatcher.add_handler(CommandHandler("save", save, filters.REPLY))
 
     updater.start_polling()
     updater.idle()