diff --git a/services.json b/services.json
new file mode 100644
index 0000000..4f545c5
--- /dev/null
+++ b/services.json
@@ -0,0 +1,15 @@
+{
+    "automat_ctd": "https://automat.renci.org/ctd/query",
+    "strider": "https://strider.renci.org/query",
+    "molepro": "https://translator.broadinstitute.org/molepro/trapi/v1.1/query",
+    "arax": "https://arax.ncats.io/api/arax/v1.1/query",
+    "text_mining": "https://api.bte.ncats.io/v1/smartapi/978fe380a147a8641caf72320862697b/query/",
+    "improving1.0": "https://evidara.healthdatascience.cloud/api/v1/query",
+    "improving1.1": "https://ia.healthdatascience.cloud/api/v1.1/query",
+    "bte": "https://api.bte.ncats.io/v1/query/",
+    "cohd1.0": "https://cohd.io/api/1.0.0/translator/query",
+    "cohd1.1": "https://cohd.io/api/1.1.0/translator/query",
+    "chp1.1": "http://chp.thayer.dartmouth.edu/query/",
+    "chp1.0": "http://chp.thayer.dartmouth.edu/v1.0/query/",
+    "cam": "https://cam-kp-api-dev.renci.org/query"
+}
\ No newline at end of file
diff --git a/tests/test_failures.py b/tests/test_failures.py
new file mode 100644
index 0000000..b13a06c
--- /dev/null
+++ b/tests/test_failures.py
@@ -0,0 +1,132 @@
+"""Test services under failure conditions."""
+import json
+import os
+
+import httpx
+import pytest
+
+with open("services.json", "r") as stream:
+    SERVICES = json.load(stream)
+PAIRS = [tuple(pair) for pair in SERVICES.items()]
+
+
+async def call_service(url, data):
+    """Call a service."""
+    headers = {"Content-Type": "application/json"}
+    async with httpx.AsyncClient(verify=False) as client:
+        response = await client.post(
+            url,
+            headers=headers,
+            data=data,
+            timeout=30.0,
+        )
+    return response.status_code, response.text
+
+
+@pytest.mark.parametrize("service_name,url", PAIRS)
+@pytest.mark.asyncio
+async def test_invalid_json(service_name, url):
+    """Test invalid JSON."""
+    data = "{"
+    status_code, text = await call_service(url, data)
+    os.makedirs("results/invalid_json", exist_ok=True)
+    with open(f"results/invalid_json/{service_name}_{status_code}.txt", "w") as stream:
+        stream.write(text)
+    assert status_code in (400, 422)
+    assert "json" in text.lower()
+
+
+@pytest.mark.parametrize("service_name,url", PAIRS)
+@pytest.mark.asyncio
+async def test_invalid_trapi(service_name, url):
+    """Test invalid TRAPI."""
+    data = json.dumps({"message": "uh oh"})
+    status_code, text = await call_service(url, data)
+    os.makedirs("results/invalid_trapi", exist_ok=True)
+    with open(f"results/invalid_trapi/{service_name}_{status_code}.txt", "w") as stream:
+        stream.write(text)
+    assert status_code in (400, 422)
+    assert "message" in text.lower()
+
+
+@pytest.mark.parametrize("service_name,url", PAIRS)
+@pytest.mark.asyncio
+async def test_broken_edge(service_name, url):
+    """Test broken edge."""
+    data = json.dumps({"message": {"query_graph": {
+        "nodes": {
+            "n0": {
+                "ids": ["MONDO:0005737"]
+            },
+            "n1": {}
+        },
+        "edges": {
+            "e01": {
+                "subject": "uh oh",
+                "object": "n1",
+            }
+        }
+    }}})
+    status_code, text = await call_service(url, data)
+    os.makedirs("results/broken_edge", exist_ok=True)
+    with open(f"results/broken_edge/{service_name}_{status_code}.txt", "w") as stream:
+        stream.write(text)
+    assert status_code in (400, 422)
+
+
+@pytest.mark.parametrize("service_name,url", PAIRS)
+@pytest.mark.asyncio
+async def test_bad_predicate(service_name, url):
+    """Test bad predicate."""
+    data = json.dumps({"message": {"query_graph": {
+        "nodes": {
+            "n0": {
+                "ids": ["MONDO:0005737"],
+                "categories": ["biolink:Disease"]
+            },
+            "n1": {
+                "categories": ["biolink:ChemicalSubstance"]
+            }
+        },
+        "edges": {
+            "e01": {
+                "subject": "n0",
+                "object": "n1",
+                "predicates": ["biolink:treats"]
+            }
+        }
+    }}})
+    status_code, text = await call_service(url, data)
+    os.makedirs("results/bad_predicate", exist_ok=True)
+    with open(f"results/bad_predicate/{service_name}_{status_code}.txt", "w") as stream:
+        stream.write(text)
+    assert status_code == 200
+
+
+@pytest.mark.parametrize("service_name,url", PAIRS)
+@pytest.mark.asyncio
+async def test_no_such_data(service_name, url):
+    """Test no such data."""
+    data = json.dumps({"message": {"query_graph": {
+        "nodes": {
+            "n0": {
+                "ids": ["MONDO:XXX"],
+                "categories": ["biolink:Disease"]
+            },
+            "n1": {
+                "categories": ["biolink:ChemicalSubstance"]
+            }
+        },
+        "edges": {
+            "e01": {
+                "subject": "n1",
+                "object": "n0",
+                "predicates": ["biolink:treats"]
+            }
+        }
+    }}})
+    status_code, text = await call_service(url, data)
+    os.makedirs("results/no_such_data", exist_ok=True)
+    with open(f"results/no_such_data/{service_name}_{status_code}.txt", "w") as stream:
+        stream.write(text)
+    assert status_code == 200