diff --git a/tests/test_api.py b/tests/test_api.py
new file mode 100644
index 0000000..dfcf505
--- /dev/null
+++ b/tests/test_api.py
@@ -0,0 +1,55 @@
+from unittest.mock import AsyncMock
+
+from fastapi.testclient import TestClient
+
+from app.models import CurrentStatus, State, utcnow
+
+
+def create(client: TestClient, url: str = "https://example.com/health") -> dict:
+    response = client.post("/v1/monitors", json={"name": "web", "url": url})
+    assert response.status_code == 201
+    return response.json()
+
+
+def test_crud_and_status(client: TestClient) -> None:
+    item = create(client)
+    assert item["current_status"]["state"] == "unknown"
+    assert client.get("/v1/monitors").json()[0]["id"] == item["id"]
+    changed = client.patch(f"/v1/monitors/{item['id']}", json={"name": "api"})
+    assert changed.status_code == 200
+    assert changed.json()["name"] == "api"
+    assert client.get(f"/v1/monitors/{item['id']}/status").json()["state"] == "unknown"
+    assert client.delete(f"/v1/monitors/{item['id']}").status_code == 204
+    missing = client.get(f"/v1/monitors/{item['id']}")
+    assert missing.status_code == 404
+    assert missing.json()["error"]["code"] == "monitor_not_found"
+
+
+def test_validation_and_operations(client: TestClient) -> None:
+    assert client.post("/v1/monitors", json={"name": "x", "url": "file:///tmp/x"}).status_code == 422
+    assert client.post("/v1/monitors", json={"name": "x", "url": "https://u:p@example.com"}).status_code == 422
+    assert client.get("/healthz").json() == {"status": "ok"}
+    ready = client.get("/readyz").json()
+    assert ready == {"status": "ready", "storage": "process-local-memory"}
+
+
+def test_check_updates_current_status(client: TestClient) -> None:
+    item = create(client)
+    result = CurrentStatus(state=State.UP, checked_at=utcnow(), latency_ms=2,
+                           http_status=204, final_url="https://example.com/health")
+    client.app.state.checker.check = AsyncMock(return_value=result)
+    checked = client.post(f"/v1/monitors/{item['id']}/check")
+    assert checked.status_code == 200
+    assert checked.json()["state"] == "up"
+    stored = client.get(f"/v1/monitors/{item['id']}/status").json()
+    assert stored["http_status"] == 204
+
+
+def test_outbound_error_is_recorded_not_raised(client: TestClient) -> None:
+    item = create(client)
+    result = CurrentStatus(state=State.ERROR, checked_at=utcnow(), latency_ms=1,
+                           error="timeout")
+    client.app.state.checker.check = AsyncMock(return_value=result)
+    response = client.post(f"/v1/monitors/{item['id']}/check")
+    assert response.status_code == 200
+    assert response.json()["error"] == "timeout"