diff --git a/.github/workflows/downstream_testing.yml b/.github/workflows/downstream_testing.yml
new file mode 100644
index 000000000..e292af9ee
--- /dev/null
+++ b/.github/workflows/downstream_testing.yml
@@ -0,0 +1,62 @@
+name: downstream_compose
+
+on:
+  push:
+    branches:
+      - downstream_compose
+
+jobs:
+  downstream-ubuntu:
+    runs-on: ubuntu-latest
+    timeout-minutes: 60
+
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - name: "pytest-django"
+            repo: "pytest-dev/pytest-django"
+            docker_profile: "postgres"
+            jobs: "test"
+            workflow_name: "main.yml"
+            matrix_exclude: |
+              linting,docs py39-dj40-mysql_innodb-coverage py36-dj22-sqlite-xdist-coverage py37-dj22-sqlite-xdist-coverage
+              py38-dj32-sqlite-xdist-coverage py38-dj40-sqlite-xdist-coverage py39-djmain-sqlite-coverage 
+              py35-dj22-postgres-pytest54-coverage py35-dj22-sqlite_file-coverage py36-dj32-mysql_myisam-coverage
+          - name: "pytest-django"
+            repo: "pytest-dev/pytest-django"
+            docker_profile: "mysql"
+            jobs: "test"
+            workflow_name: "main.yml"
+            matrix_exclude: |
+              linting,docs py310-dj40-postgres-xdist-coverage py310-dj32-postgres-xdist-coverage
+              py39-dj32-postgres-xdist-coverage py35-dj22-postgres-pytest54-coverage pypy3-dj22-postgres
+              py36-dj22-sqlite-xdist-coverage py37-dj22-sqlite-xdist-coverage py38-dj32-sqlite-xdist-coverage
+              py38-dj40-sqlite-xdist-coverage py39-djmain-sqlite-coverage py35-dj22-sqlite_file-coverage
+          - name: "pytest-django"
+            repo: "pytest-dev/pytest-django"
+            docker_profile: "nodb"
+            jobs: "test"
+            workflow_name: "main.yml"
+            matrix_exclude: |
+              linting,docs py39-dj40-mysql_innodb-coverage py35-dj22-postgres-pytest54-coverage 
+              py39-dj40-mysql_innodb-coverage py35-dj22-postgres-pytest54-coverage py36-dj32-mysql_myisam-coverage
+
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        fetch-depth: 0
+    - name: Checkout ${{ matrix.name }}
+      uses: actions/checkout@v2
+      with:
+        fetch-depth: 0
+        repository: ${{ matrix.repo }}
+        path: ${{ matrix.name }}
+    - name: Run Downstream Tests
+      run: docker-compose -f ./testing/downstream_testing/docker-compose.yml --profile ${{ matrix.docker_profile }} up --exit-code-from base_${{ matrix.docker_profile }}
+      env:
+        DS_NAME: ${{ matrix.name }}
+        DS_YAML: ./${{ matrix.name }}/.github/workflows/${{ matrix.workflow_name }}
+        DS_JOBS: ${{ matrix.jobs }}
+        DS_MATRIX_EXCLUDE: ${{ matrix.matrix_exclude }}
+        DOCKER_BUILDKIT: 1
\ No newline at end of file
diff --git a/testing/downstream_testing/action_schemas.json b/testing/downstream_testing/action_schemas.json
new file mode 100644
index 000000000..b4fdeb3fa
--- /dev/null
+++ b/testing/downstream_testing/action_schemas.json
@@ -0,0 +1,18 @@
+{
+    "pytest-django": {
+        "matrix": [
+            "matrix",
+            "include"
+        ],
+        "tox_cmd_build": {
+            "base": "name",
+            "prefix": "py",
+            "sub":
+                {
+                    "pattern": "\\-coverage$",
+                    "replace": ""
+                }
+        },
+        "python_version": "python"
+    }
+}
\ No newline at end of file
diff --git a/testing/downstream_testing/downstream_runner.py b/testing/downstream_testing/downstream_runner.py
new file mode 100644
index 000000000..625b33d34
--- /dev/null
+++ b/testing/downstream_testing/downstream_runner.py
@@ -0,0 +1,289 @@
+import argparse
+from collections import namedtuple, UserDict
+import configparser
+import json
+import logging
+import os
+import os.path
+from pprint import pprint
+import re
+import shlex
+import subprocess
+
+import sh
+from sh.contrib import git
+import yaml
+
+logging.basicConfig(format="%(levelname)s | %(module)s.%(funcName)s | %(message)s", level="INFO")
+logger = logging.getLogger(__name__)
+
+
+parser = argparse.ArgumentParser(
+    description="downstream Actions runner"
+)
+parser.add_argument(
+    "repo",
+    #nargs=1,
+    help="Name of the repo."
+)
+parser.add_argument(
+    "source",
+    nargs=1,
+    help="Path to source YAML file."
+)
+parser.add_argument(
+    "jobs",
+    nargs="+",
+    help="Job names to use."
+)
+parser.add_argument(
+    "--matrix-exclude",
+    nargs="*",
+    default=[],
+    help="Exclude these matrix names."
+)
+
+parser.add_argument(
+    "--dry-run",
+    action="store_true",
+    help="Do not run parsed downstream action. Only display the generated command list."
+)
+
+def load_matrix_schema(repo):
+    """ Loads the matrix schema for `repo` """
+    schema = None
+    working_dir = os.getcwd()
+    schema_path = os.path.join(
+        working_dir,
+        "testing",
+        "downstream_testing",
+        "action_schemas.json"
+    )
+    logger.debug("loading schema: %s", schema_path)
+    if os.path.exists(schema_path):
+        with open(schema_path) as schema_file:
+            try:
+                schema = json.load(schema_file)
+            except json.JSONDecodeError:
+                logger.error("failed to read action_schemas.json")
+    else:
+        logger.warning("action_schemas.json not found.")
+
+    if schema is not None and repo in schema:
+        schema = schema[repo]
+        logger.debug("'%s' schema loaded: %s", repo, schema)
+    else:
+        schema = None
+        logger.warning("'%s' schema not found in actions_schema.json", repo)
+
+    return schema
+
+class DownstreamRunner:
+    # TODO: actualize args vs **kwargs
+    def __init__(self, **kwargs):
+        self.yaml_source = kwargs.get("yaml_source", None)
+        if self.yaml_source == None:
+            raise SystemExit("No YAML source provided.")
+        self._yaml_tree = None
+        self.repo = kwargs.get("repo")
+        self.matrix_exclude = kwargs.get("matrix_exclude")
+        self.job_names = kwargs.get("jobs")
+        self._matrix = None
+        self._steps = None
+        self.dry_run = kwargs.get("dry_run", False)
+        self.matrix_schema = load_matrix_schema(self.repo)
+
+
+    @property
+    def yaml_tree(self):
+        """ The YAML tree built from the `yaml_source` file. """
+
+        with open(self.yaml_source) as f:
+            self._yaml_tree = yaml.safe_load(f.read())
+        
+        if self._yaml_tree == None:
+            raise SystemExit("Supplied YAML source failed to parse.")
+        
+        return self._yaml_tree
+
+    def apply_git_patches(self):
+        """ Apply any applicable git patches to the repo."""
+        if self.dry_run:
+            logger.info("Skipping all git patches (dry-run).")
+            return
+
+        working_dir = os.getcwd()
+        patches_dir = os.path.join(working_dir, "testing", "downstream_testing", "patches")
+        repo_dir = os.path.join(working_dir, self.repo)
+
+        for patch in os.listdir(patches_dir):
+            if patch.startswith(self.repo) and patch.endswith(".patch"):
+                patch_full_path = os.path.join(patches_dir, patch)
+                logger.info("Applying patch: %s", patch)
+                if not self.dry_run:
+                    if not os.getcwd() == repo_dir:
+                        os.chdir(repo_dir)
+                    try:
+                        git.config("user.email", "noreply@noreply.no")
+                        git.config("user.name", "pytest-dev")
+                        logger.info("%s", git.am(patch_full_path))
+                    except sh.ErrorReturnCode as err:
+                        logger.info(
+                            "Failed to apply '%s' to '%s': %s",
+                            patch,
+                            self.repo,
+                            str(err.stderr)
+                        )
+            else:
+                logger.info("Skipping patch: %s", patch)
+
+        if not os.getcwd() == working_dir:
+            os.chdir(working_dir)
+
+    def inject_pytest_dep(self):
+        """ Ensure pytest is a dependency in tox.ini to allow us to use the 'local'
+            version of pytest.
+        """
+        ini_path = self.repo + "/tox.ini"
+        pytest_dep = f"pytest @ file://{os.getcwd()}"
+        DEPS = {
+            "pytest": {
+                "src": f"pytest @ file://{os.getcwd()}",
+                "condition": lambda x: x.startswith("pytest") and not x.startswith("pytest-"),
+                "has_gen": lambda x: re.search(r"pytest\w*:", x)
+            },
+            "pytest-rerunfailures": {
+                "src": "pytest-rerunfailures @ git+https://github.com/pytest-dev/pytest-rerunfailures.git",
+                "condition": lambda x: x.startswith("pytest-rerunfailures"),
+                "has_gen": lambda x: re.search(r"pytest-rerunfailures\w*:", x)
+            }
+        }
+        tox_source = configparser.ConfigParser()
+        tox_source.read_file(open(ini_path))
+        #updated_deps = set()
+        found_pytest = False
+        for section in tox_source.sections():
+            updated_deps = set()
+            section_deps = tox_source.get(section, "deps", fallback=None)
+            if section_deps:
+                for dep in section_deps.split("\n"):
+                    for check_dep in DEPS:
+                        if DEPS[check_dep]["condition"](dep):
+                            has_gen = DEPS[check_dep]["has_gen"](dep)
+                            if has_gen is not None and not found_pytest:
+                                found_pytest = True
+                                updated_deps.add(f"!{has_gen.group()} {DEPS[check_dep]['src']}")
+                updated_deps = '\n'.join(updated_deps)
+                tox_source[section]["deps"] = f"{tox_source[section]['deps']}\n{updated_deps}"
+
+        with open(ini_path, "w") as f:
+            tox_source.write(f)
+
+    def __repr__(self):
+        return str(
+            "DownstreamRunner("
+            f"repo={self.repo}, "
+            f"yaml_source={self.yaml_source}, "
+            f"job_names={self.job_names}, "
+            f"matrix={self.matrix}, "
+            f"steps={self.steps}"
+            ")"
+        )
+
+    @property
+    def matrix(self):
+        def parse_matrix(yaml_tree):
+            parsed_matrix = yaml_tree
+            for key in self.matrix_schema["matrix"]:
+                parsed_matrix = parsed_matrix[key]
+                #logger.debug("%s", parsed_matrix)
+            if parsed_matrix != yaml_tree:
+                tox_base = self.matrix_schema["tox_cmd_build"]["base"]
+                tox_prefix = self.matrix_schema["tox_cmd_build"]["prefix"]
+                skip_matrices = []
+                for item in parsed_matrix:
+                    if (not item[tox_base].startswith(tox_prefix) or
+                        item[tox_base] in self.matrix_exclude
+                    ):
+                        skip_matrices.append(item)
+                        continue
+                    item["tox_cmd"] = re.sub(
+                        self.matrix_schema["tox_cmd_build"]["sub"]["pattern"],
+                        self.matrix_schema["tox_cmd_build"]["sub"]["replace"],
+                        item[tox_base]
+                    )
+                    #logger.debug("re.sub: %s", item[tox_base])
+                for matrice in skip_matrices:
+                    parsed_matrix.remove(matrice)
+                
+            return parsed_matrix
+
+        if self._matrix is None:
+            matrix_items = {}
+            for job in self.job_names:
+                job_yaml = self.yaml_tree["jobs"][job]["strategy"]
+                parsed_matrix = parse_matrix(job_yaml)
+                matrix_items[job] = parsed_matrix
+                
+
+            self._matrix = matrix_items
+        logger.debug("matrix: %s", self._matrix)
+        return self._matrix
+
+    @property
+    def steps(self):
+        if self._steps is None:
+            step_items = {}
+            for job in self.job_names:
+                if job not in step_items:
+                    step_items[job] = []
+                for item in self.yaml_tree["jobs"][job]["steps"]:
+                    if "run" in item:
+                        step_items[job].append(item)
+            self._steps = step_items
+        return self._steps
+    
+    def build_run(self):
+        run = {}
+        for job in self.job_names:
+            logger.debug("job_name: %s", job)
+            for matrix in self.matrix[job]:
+                logger.debug("matrix[job]: %s", matrix)
+                run[matrix["name"]] = [
+                    "pip install tox",
+                    f"tox -e {matrix['tox_cmd']}"
+                ]
+
+        logger.debug("built run: %s", run)
+        return run
+
+    def run(self):
+        self.apply_git_patches()
+        self.inject_pytest_dep()
+        run_steps = self.build_run()
+        os.chdir(self.repo)
+        for matrix, steps in run_steps.items():
+            for step in steps:
+                cmd = shlex.split(step)
+                logger.info("--> running: '%s'", step)
+                if not self.dry_run:
+                    subprocess.run(
+                        cmd,
+                        encoding="utf-8",
+                        check=True
+                    )
+
+if __name__ == "__main__":
+    cli_args = parser.parse_args()
+    if cli_args.dry_run:
+        logger.setLevel("DEBUG")
+    runner_args = {
+        "repo": cli_args.repo,
+        "yaml_source": cli_args.source[0],
+        "jobs": cli_args.jobs,
+        "matrix_exclude": cli_args.matrix_exclude,
+        "dry_run": cli_args.dry_run,
+    }
+    runner = DownstreamRunner(**runner_args)
+
+    runner.run()
\ No newline at end of file