diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 9d96e9f8..2000c2bb 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -63,3 +63,24 @@ jobs:
       env:
         UNSTRUCTURED_API_KEY: ${{ secrets.UNSTRUCTURED_API_KEY }}
 
+  test_contract:
+    strategy:
+      matrix:
+        python-version: [ "3.9","3.10","3.11", "3.12" ]
+    runs-on: ubuntu-latest
+    env:
+      POETRY_VIRTUALENVS_IN_PROJECT: "true"
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+      - name: Install dependencies
+        run: |
+          make install
+          source .venv/bin/activate && make install-test-contract
+      - name: Run unit tests
+        run: |
+          poetry run make test-contract
+
diff --git a/Makefile b/Makefile
index 8f97a22b..4233335c 100644
--- a/Makefile
+++ b/Makefile
@@ -19,6 +19,11 @@ install:
 install-speakeasy-cli:
 	curl -fsSL https://raw.githubusercontent.com/speakeasy-api/speakeasy/main/install.sh | sh
 
+## install-test:				install test requirements as they cannot be put into pyproject.toml due to python version requirements mismatch
+.PHONY: install-test-contract
+install-test-contract:
+	pip install unstructured pytest-httpx
+
 #################
 # Test and Lint #
 #################
@@ -30,6 +35,10 @@ test: test-unit test-integration-docker
 test-unit:
 	PYTHONPATH=. pytest _test_unstructured_client -v -k "unit"
 
+.PHONY: test-contract
+test-contract:
+	PYTHONPATH=. pytest _test_contract -v
+
 # Assumes you have unstructured-api running on localhost:8000
 .PHONY: test-integration
 test-integration:
diff --git a/_test_contract/test_partition_via_api.py b/_test_contract/test_partition_via_api.py
new file mode 100644
index 00000000..1e367d9d
--- /dev/null
+++ b/_test_contract/test_partition_via_api.py
@@ -0,0 +1,135 @@
+import os
+from pathlib import Path
+
+import httpx
+import pytest
+from unstructured.partition.api import partition_via_api
+
+from unstructured_client import UnstructuredClient
+
+
+@pytest.fixture(scope="module")
+def client() -> UnstructuredClient:
+    _client = UnstructuredClient(api_key_auth=os.getenv("UNSTRUCTURED_API_KEY"), server='free-api')
+    yield _client
+
+
+@pytest.fixture(scope="module")
+def doc_path() -> Path:
+    samples_path = Path(__file__).resolve().parents[1] / "_sample_docs"
+    assert samples_path.exists()
+    return samples_path
+
+
+MOCK_TEXT = """[
+    {
+        "element_id": "f49fbd614ddf5b72e06f59e554e6ae2b",
+        "text": "This is a test email to use for unit tests.",
+        "type": "NarrativeText",
+        "metadata": {
+            "sent_from": [
+                "Matthew Robinson <mrobinson@unstructured.io>"
+            ],
+            "sent_to": [
+                "Matthew Robinson <mrobinson@unstructured.io>"
+            ],
+            "subject": "Test Email",
+            "filename": "fake-email.eml",
+            "filetype": "message/rfc822"
+        }
+    }
+]"""
+
+
+@pytest.mark.parametrize(
+    ("url", "full_url"), [
+        ("http://localhost:8000", "http://localhost:8000/general/v0/general"),
+        ("http://localhost:8000/general/v0/general", "http://localhost:8000/general/v0/general"),
+    ]
+)
+def test_partition_via_api_custom_url(httpx_mock, doc_path: Path, url: str, full_url: str):
+    """
+    Assert that we can specify api_url and requests are sent to the right place
+    """
+
+    filename = "layout-parser-paper-fast.pdf"
+
+    # adding response automatically checks whether a response to a request to given URL was found
+    httpx_mock.add_response(
+        method="POST",
+        url=full_url,
+        headers={"Content-Type": "application/json"},
+        content=MOCK_TEXT.encode(),
+    )
+
+    partition_via_api(filename=str(doc_path / filename), api_url=url, metadata_filename=filename)
+
+
+def test_partition_via_api_pass_list_type_parameters(httpx_mock, doc_path: Path):
+    url = "http://localhost:8000/general/v0/general"
+    filename = "layout-parser-paper-fast.pdf"
+
+    httpx_mock.add_response(
+        method="POST",
+        headers={"Content-Type": "application/json"},
+        content=MOCK_TEXT.encode(),
+        url=url,
+    )
+
+    params = dict(
+        split_pdf_page=False,
+        strategy="hi_res",
+        extract_image_block_types=["image", "table"],
+        skip_infer_table_types=["pdf", "docx"],
+        languages=["eng"],
+    )
+
+    partition_via_api(filename=str(doc_path / filename),
+                      api_url=url,
+                      metadata_filename=filename,
+                      **params)
+
+    requests = httpx_mock.get_requests()
+
+    assert len(requests) == 1
+
+    request = requests[0]
+
+    parsed_multipart_form = _parse_multipart_data(request)
+    assert "coordinates" in parsed_multipart_form
+    for key, value in params.items():
+        assert key in parsed_multipart_form
+        assert parsed_multipart_form[key] == value
+
+
+def _parse_multipart_data(request: httpx.Request) -> dict:
+    """Parser for multipart form data in raw format to a dictionary. Ommits "files" field
+    Includes table-like entries.
+    """
+    data = request.content
+    boundary = request.headers["Content-Type"].split("boundary=")[1]
+    parts = data.split(f"--{boundary}".encode())
+    parts = [part.strip() for part in parts if part.strip()]
+    parsed_data = {}
+    for part in parts:
+        if b"Content-Disposition: form-data" in part:
+            try:
+                semicolon_pos = part.find(b";")
+                contents = part[semicolon_pos + 2:]
+                if b"name=\"files\"" in contents:
+                    continue
+                contents = contents.decode()
+                key, value = contents.split("\r\n\r\n")
+                key = key.replace("name=", "").strip('"')
+                if "[]" in key:
+                    key = key.replace("[]", "")
+                    if key not in parsed_data:
+                        parsed_data[key] = []
+                    parsed_data[key].append(value)
+                elif value in ["true", "false"]:
+                    parsed_data[key] = value == "true"
+                else:
+                    parsed_data[key] = value
+            except Exception as ex:
+                print(ex)
+    return parsed_data