diff --git a/requirements.txt b/requirements.txt
index 1ac5fd2b..3b8f6b5c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,9 +1,11 @@
-fastapi>=0.66
-aiofiles
-uvicorn
-numpy
-python-ags4
-python-multipart
-colorlog
-shortuuid
-jinja2
+aiofiles==0.7.0
+numpy==1.21.2
+python-ags4==0.3.6
+python-multipart==0.0.5
+colorlog==5.0.1
+shortuuid==1.0.1
+Jinja2==3.0.1
+# These libraries are already in FastAPI container but need updated
+fastapi==0.68.0
+uvicorn==0.15.0
+h11==0.12.0
diff --git a/requirements_dev.txt b/requirements_dev.txt
index 046019cc..54837b1e 100644
--- a/requirements_dev.txt
+++ b/requirements_dev.txt
@@ -2,3 +2,4 @@ ipython
 ipdb
 pytest
 flake8
+requests
diff --git a/test/integration/test_api.py b/test/integration/test_api.py
new file mode 100644
index 00000000..e7ebaa02
--- /dev/null
+++ b/test/integration/test_api.py
@@ -0,0 +1,45 @@
+"""Tests for API responses."""
+from pathlib import Path
+import re
+
+from fastapi.testclient import TestClient
+import pytest
+
+from app.main import app
+
+TEST_FILE_DIR = Path(__file__).parent.parent / 'files'
+
+
+def test_openapi_json(client):
+    """A hello-world type test to confirm testing framework works."""
+    response = client.get('/openapi.json')
+    assert response.status_code == 200
+    assert '/validate' in response.text
+
+
+@pytest.mark.parametrize('filename, expected', [
+    ('example1.ags', 'All checks passed!'),
+    ('nonsense.ags', r'7 error\(s\) found in file!'),
+    ('empty.ags', r'4 error\(s\) found in file!'),
+    ('real/A3040_03.ags', r'5733 error\(s\) found in file!'),
+    ('example1.xlsx', 'ERROR: Only .ags files are accepted as input.'),
+    ('random_binary.ags', 'ERROR: Unreadable character "á" at position 1 on line: 1\nStarting:'),
+    ('real/CG014058_F.ags', r'ERROR: Unreadable character "æ" at position 80 on line: 263'),
+    ('real/Blackburn Southern Bypass.ags', r'93 error\(s\) found in file!'),  # this file contains BOM character
+])
+def test_validate(client, filename, expected):
+    # Arrange
+    filename = TEST_FILE_DIR / filename
+
+    # Act
+    response = client.post('/validate/?fmt=text',
+                           files={'file': (filename.name, str(filename))})
+
+    # Assert
+    assert response.status_code == 200
+    assert re.search(expected, response.text)
+
+
+@pytest.fixture(scope="function")
+def client():
+    return TestClient(app)