feat: add nix support

default.nix

@@ -0,0 +1,10 @@
+(import
+  (
+    let lock = builtins.fromJSON (builtins.readFile ./flake.lock);
+    in fetchTarball {
+      url = "https://github.com/edolstra/flake-compat/archive/${lock.nodes.flake-compat.locked.rev}.tar.gz";
+      sha256 = lock.nodes.flake-compat.locked.narHash;
+    }
+  )
+  { src = ./.; }
+).defaultNix

flake.nix

@@ -0,0 +1,87 @@
+{
+  description = "agentmail - Python SDK";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-25.11";
+    flake-utils.url = "github:numtide/flake-utils";
+    flake-compat.url = "github:edolstra/flake-compat";
+    flake-compat.flake = false;
+  };
+
+  outputs = { self, nixpkgs, flake-utils, flake-compat, ... }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+        python = pkgs.python3;
+
+        agentmail = python.pkgs.buildPythonPackage {
+          pname = "agentmail";
+          version = "0.2.10";
+          format = "pyproject";
+          src = ./.;
+
+          nativeBuildInputs = [
+            python.pkgs.poetry-core
+          ];
+
+          propagatedBuildInputs = with python.pkgs; [
+            httpx
+            pydantic
+            pydantic-core
+            typing-extensions
+            websockets
+          ];
+
+          pythonImportsCheck = [ "agentmail" ];
+
+          # Tests require network access / API keys
+          doCheck = false;
+        };
+      in
+      {
+        packages.default = agentmail;
+
+        devShells.default = pkgs.mkShell {
+          packages = [
+            (python.withPackages (ps: [
+              agentmail
+              ps.pytest
+              ps.pytest-asyncio
+              ps.pytest-xdist
+              ps.python-dateutil
+              ps.mypy
+              ps.ruff
+            ]))
+          ];
+        };
+      }
+    ) // {
+      overlays.default = final: prev: {
+        pythonPackagesExtensions = (prev.pythonPackagesExtensions or []) ++ [
+          (python-final: python-prev: {
+            agentmail = python-final.buildPythonPackage {
+              pname = "agentmail";
+              version = "0.2.10";
+              format = "pyproject";
+              src = self;
+
+              nativeBuildInputs = [
+                python-final.poetry-core
+              ];
+
+              propagatedBuildInputs = with python-final; [
+                httpx
+                pydantic
+                pydantic-core
+                typing-extensions
+                websockets
+              ];
+
+              pythonImportsCheck = [ "agentmail" ];
+              doCheck = false;
+            };
+          })
+        ];
+      };
+    };
+}