diff --git a/.github/workflows/code-formatting.yml b/.github/workflows/code-formatting.yml
index 203c0fb846..3e2f296226 100644
--- a/.github/workflows/code-formatting.yml
+++ b/.github/workflows/code-formatting.yml
@@ -22,70 +22,21 @@ jobs:
       - name: Run isort
         run: isort --settings-path=./pyproject.toml --check-only --diff .
 
-  code-black:
-    name: Check code formatting with Black
-    runs-on: ubuntu-20.04
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-      - name: Set up Python 3.8
-        uses: actions/setup-python@v2
-        with:
-          python-version: 3.8
-      - name: Install Black
-        run: pip install black==19.10b0
-      - name: Run Black
-        run: echo "LGTM"
-        # run black --skip-string-normalization --config=pyproject.toml --check . # TODO, uncomment
-
-  python-types:
-    name: Python static type checking with Pyright
-    runs-on: ubuntu-20.04
-
-    # Timeout: https://stackoverflow.com/a/59076067/4521646
-    timeout-minutes: 15
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-      - uses: actions/setup-python@v2
-        with:
-          python-version: 3.7
-
-      # Note: This uses an internal pip API and may not always work
-      # https://github.com/actions/cache/blob/master/examples.md#multiple-oss-in-a-workflow
-      - name: Cache pip
-        uses: actions/cache@v2
-        with:
-          path: ~/.cache/pip
-          key: ${{ runner.os }}-pip-extras-${{ hashFiles('requirements.txt') }}-${{ hashFiles('requirements/extra.txt') }}
-          restore-keys: |
-            ${{ runner.os }}-pip-extras-
-
-      - name: Install dependencies
-        env:
-          HOROVOD_BUILD_ARCH_FLAGS: "-mfma"
-          HOROVOD_WITHOUT_MXNET: 1
-          HOROVOD_WITHOUT_TENSORFLOW: 1
-        run: |
-          # python -m pip install --upgrade --user pip
-          pip install --requirement requirements.txt --upgrade-strategy only-if-needed --find-links https://download.pytorch.org/whl/cpu/torch_stable.html --quiet
-          pip install --requirement ./requirements/devel.txt --quiet
-          # pip install tox coverage
-          python --version ; pip --version ; pip list
-        shell: bash
-
-      - name: Set up node
-        uses: actions/setup-node@v1
-        with:
-          node-version: '12'
-
-      - name: Install pyright
-        run: |
-          npm install pyright
-
-      - name: Run type checking
-        run: |
-          $(npm bin)/pyright --project .pyrightconfig.json
+  #code-black:
+  #  name: Check code formatting with Black
+  #  runs-on: ubuntu-20.04
+  #  steps:
+  #    - name: Checkout
+  #      uses: actions/checkout@v2
+  #    - name: Set up Python 3.8
+  #      uses: actions/setup-python@v2
+  #      with:
+  #        python-version: 3.8
+  #    - name: Install Black
+  #      run: pip install black==19.10b0
+  #    - name: Run Black
+  #      run: echo "LGTM"
+  #      run black --skip-string-normalization --config=pyproject.toml --check . # TODO, uncomment
 
   python-pep8:
     name: Python formatting PEP8
@@ -107,3 +58,19 @@ jobs:
       - name: Run checking
         run: |
           flake8 .
+
+  python-typing-mypy:
+    name: Python typing check [mypy]
+    runs-on: ubuntu-20.04
+    steps:
+      - uses: actions/checkout@master
+      - uses: actions/setup-python@v2
+        with:
+          python-version: 3.8
+      - name: Install mypy
+        run: |
+          pip install mypy
+          pip list
+      - name: mypy check
+        run: |
+          mypy
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 9b481e9ecf..78684a2ab7 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -30,3 +30,7 @@ repos:
         args: [--settings-path, ./pyproject.toml]
         language: system
         types: [python]
+
+  - repo: https://github.com/pre-commit/mirrors-mypy
+    hooks:
+      - id: mypy
diff --git a/.pyrightconfig.json b/.pyrightconfig.json
deleted file mode 100644
index 416b33f6ad..0000000000
--- a/.pyrightconfig.json
+++ /dev/null
@@ -1,46 +0,0 @@
-{
-  "include": [
-    "pytorch_lightning"
-  ],
-
-  "ignore": [
-    "pytorch_lightning/__init__.py",
-    "pytorch_lightning/callbacks",
-    "pytorch_lightning/core",
-    "pytorch_lightning/accelerators",
-    "pytorch_lightning/loggers",
-    "pytorch_lightning/logging",
-    "pytorch_lightning/metrics",
-    "pytorch_lightning/overrides",
-    "pytorch_lightning/profiler",
-    "pytorch_lightning/pt_overrides",
-    "pytorch_lightning/root_module",
-    "pytorch_lightning/utilities",
-    "pytorch_lightning/trainer/data_loading.py",
-    "pytorch_lightning/trainer/deprecated_api.py",
-    "pytorch_lightning/trainer/distrib_parts.py",
-    "pytorch_lightning/trainer/evaluation_loop.py",
-    "pytorch_lightning/trainer/logging.py",
-    "pytorch_lightning/trainer/lr_finder.py",
-    "pytorch_lightning/trainer/optimizers.py",
-    "pytorch_lightning/trainer/supporters.py",
-    "pytorch_lightning/trainer/trainer.py",
-    "pytorch_lightning/trainer/training_io.py",
-    "pytorch_lightning/trainer/training_loop.py",
-    "pytorch_lightning/trainer/training_tricks.py",
-    "pytorch_lightning/trainer/batch_size_scaling.py",
-    "pytorch_lightning/trainer/distrib_data_parallel.py",
-    "pytorch_lightning/trainer/properties.py",
-    "pytorch_lightning/trainer/lr_scheduler_connector.py",
-    "pytorch_lightning/trainer/training_loop_temp.py",
-    "pytorch_lightning/trainer/connectors/checkpoint_connector.py",
-    "pytorch_lightning/trainer/connectors/data_connector.py",
-    "pytorch_lightning/trainer/connectors/logger_connector.py",
-    "pytorch_lightning/trainer/connectors/slurm_connector.py",
-    "pytorch_lightning/distributed/dist.py",
-    "pytorch_lightning/tuner",
-    "pytorch_lightning/plugins"
-  ],
-
-  "reportMissingImports": false
-}
diff --git a/pytorch_lightning/__init__.py b/pytorch_lightning/__init__.py
index f543e4382c..2a73974223 100644
--- a/pytorch_lightning/__init__.py
+++ b/pytorch_lightning/__init__.py
@@ -47,9 +47,9 @@ try:
     # This variable is injected in the __builtins__ by the build
     # process. It used to enable importing subpackages of skimage when
     # the binaries are not built
-    __LIGHTNING_SETUP__
+    _ = None if __LIGHTNING_SETUP__ else None
 except NameError:
-    __LIGHTNING_SETUP__ = False
+    __LIGHTNING_SETUP__: bool = False
 
 if __LIGHTNING_SETUP__:
     import sys  # pragma: no-cover
diff --git a/pytorch_lightning/setup_tools.py b/pytorch_lightning/setup_tools.py
index c29076c41f..590d2d396b 100644
--- a/pytorch_lightning/setup_tools.py
+++ b/pytorch_lightning/setup_tools.py
@@ -15,6 +15,7 @@
 import os
 import re
 import warnings
+from typing import Iterable, List
 from urllib.error import HTTPError, URLError
 from urllib.request import Request, urlopen
 
@@ -37,7 +38,7 @@ _DEFAULT_BADGES = [
 ]
 
 
-def _load_requirements(path_dir, file_name='requirements.txt', comment_char='#'):
+def _load_requirements(path_dir: str , file_name: str = 'requirements.txt', comment_char: str = '#') -> List[str]:
     """Load requirements from a file
 
     >>> _load_requirements(PROJECT_ROOT)  # doctest: +ELLIPSIS +NORMALIZE_WHITESPACE
@@ -58,7 +59,7 @@ def _load_requirements(path_dir, file_name='requirements.txt', comment_char='#')
     return reqs
 
 
-def _parse_for_badge(text: str, path_badges: str = _PATH_BADGES, badge_names: list = _DEFAULT_BADGES):
+def _parse_for_badge(text: str, path_badges: str = _PATH_BADGES, badge_names: Iterable = _DEFAULT_BADGES) -> str:
     """ Returns the new parsed text with url change with local downloaded files
 
     >>> _parse_for_badge('Some text here... '  # doctest: +ELLIPSIS +NORMALIZE_WHITESPACE
@@ -90,12 +91,12 @@ def _parse_for_badge(text: str, path_badges: str = _PATH_BADGES, badge_names: li
     return text
 
 
-def _save_file(url_badge, save, extension, headers):
+def _save_file(url_badge: str, save_path: str, extension: str, headers: dict) -> None:
     """function for saving the badge either in `.png` or `.svg`"""
 
     # because there are two badge with name `PyPI Status` the second one is download
     if 'https://pepy.tech/badge/pytorch-lightning' in url_badge:
-        save += '_downloads'
+        save_path += '_downloads'
 
     try:
         req = Request(url=url_badge, headers=headers)
@@ -103,12 +104,12 @@ def _save_file(url_badge, save, extension, headers):
     except URLError:
         warnings.warn("Error while downloading the badge", UserWarning)
     else:
-        save += extension
-        with open(save, 'wb') as download_file:
+        save_path += extension
+        with open(save_path, 'wb') as download_file:
             download_file.write(resp.read())
 
 
-def _download_badge(url_badge, badge_name, target_dir):
+def _download_badge(url_badge: str, badge_name: str, target_dir: str) -> str:
     """Download badge from url
 
     >>> path_img = _download_badge('https://img.shields.io/pypi/pyversions/pytorch-lightning',
@@ -143,9 +144,10 @@ def _download_badge(url_badge, badge_name, target_dir):
                 url_badge = url_badge.replace('.png', '.svg')
                 _save_file(url_badge, save_path, extension='.svg', headers=headers)
                 return save_path + '.svg'
+            return ''
 
 
-def _load_long_description(path_dir):
+def _load_long_description(path_dir: str) -> str:
     """Load readme as decribtion
 
     >>> _load_long_description(PROJECT_ROOT)  # doctest: +ELLIPSIS +NORMALIZE_WHITESPACE
diff --git a/requirements/test.txt b/requirements/test.txt
index 74c62f82c7..3cb538a98d 100644
--- a/requirements/test.txt
+++ b/requirements/test.txt
@@ -12,6 +12,7 @@ scikit-learn>=0.22.2
 scikit-image>=0.17.2
 black>=20.8b1
 isort>=5.6.4
+mypy>=0.720
 pre-commit>=1.0
 
 cloudpickle>=1.3
diff --git a/setup.cfg b/setup.cfg
index 2802806f60..b0c2c8640b 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -93,3 +93,88 @@ convention = pep257
 # D202: Ignore a blank line after docstring (collision with Python Black in decorators)
 add-ignore = D104,D107,D202
 max-line-length = 120
+
+
+[mypy]
+# Typing tests is low priority, but enabling type checking on the
+# untyped test functions (using `--check-untyped-defs`) is still
+# high-value because it helps test the typing.
+files = pytorch_lightning, pl_examples, benchmarks, tests
+disallow_untyped_defs = True
+ignore_missing_imports = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.callbacks.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.core.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.accelerators.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.cluster_environments.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.loggers.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.logging.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.metrics.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.overrides.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.profiler.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.pt_overrides.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.plugins.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.root_module.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.trainer.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.distributed.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.tuner.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pytorch_lightning.utilities.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-pl_examples.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-benchmarks.*]
+ignore_errors = True
+
+# todo: add proper typing to this module...
+[mypy-tests.*]
+ignore_errors = True