diff --git a/pkgs/development/python-modules/deal-solver/default.nix b/pkgs/development/python-modules/deal-solver/default.nix
new file mode 100644
index 000000000000..d3101f73e540
--- /dev/null
+++ b/pkgs/development/python-modules/deal-solver/default.nix
@@ -0,0 +1,68 @@
+{ lib
+, buildPythonPackage
+, fetchFromGitHub
+, pythonOlder
+, flit-core
+, z3
+, astroid
+, pytestCheckHook
+, hypothesis
+}:
+
+buildPythonPackage rec {
+  pname = "deal-solver";
+  version = "0.1.0";
+  format = "pyproject";
+  disabled = pythonOlder "3.6";
+
+  src = fetchFromGitHub {
+    owner = "life4";
+    repo = pname;
+    rev = "refs/tags/${version}";
+    hash = "sha256-eSSyLBwPc0rrfew91nLBagYDD6aJRyx0cE9YTTSODI8=";
+  };
+
+  nativeBuildInputs = [
+    flit-core
+  ];
+
+  postPatch = ''
+    # Use upstream z3 implementation
+    substituteInPlace pyproject.toml \
+      --replace "\"z3-solver\"," "" \
+      --replace "\"--cov=deal_solver\"," "" \
+      --replace "\"--cov-report=html\"," "" \
+      --replace "\"--cov-report=xml\"," "" \
+      --replace "\"--cov-report=term-missing:skip-covered\"," "" \
+      --replace "\"--cov-fail-under=100\"," ""
+  '';
+
+  propagatedBuildInputs = [
+    z3
+    astroid
+  ];
+
+  checkInputs = [
+    pytestCheckHook
+    hypothesis
+  ];
+
+  disabledTests = [
+    # z3 assertion error
+    "test_expr_asserts_ok"
+  ];
+
+  disabledTestPaths = [
+    # regex matching seems flaky on tests
+    "tests/test_stdlib/test_re.py"
+  ];
+
+  pythonImportsCheck = [ "deal_solver" ];
+
+  meta = with lib; {
+    description = "Z3-powered solver (theorem prover) for deal";
+    homepage = "https://github.com/life4/deal-solver";
+    license = licenses.mit;
+    maintainers = with maintainers; [ gador ];
+  };
+}
diff --git a/pkgs/development/python-modules/deal/default.nix b/pkgs/development/python-modules/deal/default.nix
new file mode 100644
index 000000000000..5f887848453b
--- /dev/null
+++ b/pkgs/development/python-modules/deal/default.nix
@@ -0,0 +1,100 @@
+{ lib
+, buildPythonPackage
+, pythonOlder
+, fetchFromGitHub
+, flit-core
+, astroid
+, pytestCheckHook
+, docstring-parser
+, isort
+, marshmallow
+, pytest-cov
+, sphinx
+, hypothesis
+, vaa
+, deal-solver
+, pygments
+, typeguard
+, coverage
+, urllib3
+}:
+
+buildPythonPackage rec {
+  pname = "deal";
+  version = "4.23.3";
+  format = "pyproject";
+  disabled = pythonOlder "3.7";
+
+  src = fetchFromGitHub {
+    owner = "life4";
+    repo = pname;
+    rev = "refs/tags/${version}";
+    hash = "sha256-duFxe2KSQQb7HB5KrrE32xzTb6QkQcrQssiuXLKao50=";
+  };
+
+  postPatch = ''
+    # don't do coverage
+    substituteInPlace pyproject.toml \
+      --replace "\"--cov-fail-under=100\"," "" \
+      --replace "\"--cov=deal\"," "" \
+      --replace "\"--cov-report=html\"," "" \
+      --replace "\"--cov-report=term-missing:skip-covered\"," ""
+  '';
+
+  nativeBuildInputs = [
+    flit-core
+  ];
+
+  propagatedBuildInputs = [
+    astroid
+    deal-solver
+    pygments
+    typeguard
+  ];
+
+  checkInputs = [
+    pytestCheckHook
+
+    docstring-parser
+    marshmallow
+    sphinx
+    hypothesis
+    vaa
+    urllib3
+  ];
+
+  disabledTests = [
+    # needs internet access
+    "test_smoke_has"
+    "test_pure_offline"
+    "test_raises_doesnt_override_another_contract"
+    "test_raises_doesnt_override_another_contract_async"
+    "test_raises_generator"
+    # AttributeError: module 'vaa' has no attribute 'Error'
+    "test_source_vaa_scheme"
+    "test_vaa_scheme_and_custom_exception"
+    "test_scheme_string_validation_args_correct"
+    "test_method_chain_decorator_with_scheme_is_fulfilled"
+    "test_scheme_contract_is_satisfied_when_setting_arg"
+    "test_scheme_contract_is_satisfied_within_chain"
+    "test_scheme_errors_rewrite_message"
+  ];
+
+  disabledTestPaths = [
+    # needs internet access
+    "tests/test_runtime/test_offline.py"
+  ];
+
+  pythonImportsCheck = [ "deal" ];
+
+  meta = with lib; {
+    description = "Library for design by contract (DbC) and checking values, exceptions, and side-effects";
+    longDescription = ''
+      In a nutshell, deal empowers you to write bug-free code.
+      By adding a few decorators to your code, you get for free tests, static analysis, formal verification, and much more
+    '';
+    homepage = "https://github.com/life4/deal";
+    license = licenses.mit;
+    maintainers = with maintainers; [ gador ];
+  };
+}
diff --git a/pkgs/development/python-modules/pyschemes/default.nix b/pkgs/development/python-modules/pyschemes/default.nix
new file mode 100644
index 000000000000..c7034d11cdca
--- /dev/null
+++ b/pkgs/development/python-modules/pyschemes/default.nix
@@ -0,0 +1,34 @@
+{ lib
+, buildPythonPackage
+, fetchFromGitHub
+, pythonAtLeast
+, pytestCheckHook
+}:
+
+buildPythonPackage rec {
+  pname = "pyschemes";
+  version = "unstable-2017-11-08";
+  format = "setuptools";
+
+  disabled = pythonAtLeast "3.10";
+
+  src = fetchFromGitHub {
+    owner = "spy16";
+    repo = pname;
+    rev = "ca6483d13159ba65ba6fc2f77b90421c40f2bbf2";
+    hash = "sha256-PssucudvlE8mztwVme70+h+2hRW/ri9oV9IZayiZhdU=";
+  };
+
+  checkInputs = [
+    pytestCheckHook
+  ];
+
+  pythonImportsCheck = [ "pyschemes" ];
+
+  meta = with lib; {
+    description = "A library for validating data structures in Python";
+    homepage = "https://github.com/spy16/pyschemes";
+    license = licenses.wtfpl;
+    maintainers = with maintainers; [ gador ];
+  };
+}
diff --git a/pkgs/development/python-modules/vaa/default.nix b/pkgs/development/python-modules/vaa/default.nix
new file mode 100644
index 000000000000..783cc7bd6811
--- /dev/null
+++ b/pkgs/development/python-modules/vaa/default.nix
@@ -0,0 +1,56 @@
+{ lib
+, buildPythonPackage
+, fetchFromGitHub
+, flit-core
+, pytestCheckHook
+, cerberus
+, django
+, djangorestframework
+, marshmallow
+, pyschemes
+, wtforms
+, email_validator
+}:
+
+buildPythonPackage rec {
+  pname = "vaa";
+  version = "0.2.1";
+  format = "pyproject";
+
+  src = fetchFromGitHub {
+    owner = "life4";
+    repo = pname;
+    rev = "refs/tags/v.${version}";
+    hash = "sha256-24GTTJSZ55ejyHoWP1/S3DLTKvOolAJr9UhWoOm84CU=";
+  };
+
+  postPatch = ''
+    substituteInPlace pyproject.toml \
+      --replace "requires = [\"flit\"]" "requires = [\"flit_core\"]" \
+      --replace "build-backend = \"flit.buildapi\"" "build-backend = \"flit_core.buildapi\""
+  '';
+
+  nativeBuildInputs = [
+    flit-core
+  ];
+
+  checkInputs = [
+    pytestCheckHook
+    cerberus
+    django
+    djangorestframework
+    marshmallow
+    pyschemes
+    wtforms
+    email_validator
+  ];
+
+  pythonImportsCheck = [ "vaa" ];
+
+  meta = with lib; {
+    description = "VAlidators Adapter makes validation by any existing validator with the same interface";
+    homepage = "https://github.com/life4/vaa";
+    license = licenses.mit;
+    maintainers = with maintainers; [ gador ];
+  };
+}
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index c4c53ddcb76e..f0ee37cbd6ab 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -2135,6 +2135,10 @@ in {
 
   ddt = callPackage ../development/python-modules/ddt { };
 
+  deal = callPackage ../development/python-modules/deal { };
+
+  deal-solver = callPackage ../development/python-modules/deal-solver { };
+
   deap = callPackage ../development/python-modules/deap { };
 
   debian = callPackage ../development/python-modules/debian { };
@@ -6531,6 +6535,8 @@ in {
 
   pysbd = callPackage ../development/python-modules/pysbd { };
 
+  pyschemes = callPackage ../development/python-modules/pyschemes { };
+
   pyshark = callPackage ../development/python-modules/pyshark { };
 
   pysiaalarm = callPackage ../development/python-modules/pysiaalarm { };
@@ -10839,6 +10845,8 @@ in {
     inherit (pkgs.darwin.apple_sdk.frameworks) ApplicationServices CoreServices;
   };
 
+  vaa = callPackage ../development/python-modules/vaa { };
+
   validate-email = callPackage ../development/python-modules/validate-email { };
 
   validators = callPackage ../development/python-modules/validators { };