diff --git a/README.md b/README.md
index 423f05b..8fcde6e 100644
--- a/README.md
+++ b/README.md
@@ -67,7 +67,7 @@ project = client.create_project(
 
 generation = client.create_generation(
     apiProjectId=project.apiProjectId,
-    model="diffio-3.5",
+    model="diffio-4.0-flash",
     sampling={"steps": 12, "guidance": 1.5},
     idempotencyKey="restore-job-2026-001",
     requestOptions={"maxRetries": 2},
@@ -89,7 +89,7 @@ from diffio import DiffioClient
 client = DiffioClient(apiKey="diffio_live_...")
 result = client.audio_isolation.isolate(
     filePath="sample.wav",
-    model="diffio-3.5",
+    model="diffio-4.0-flash",
     sampling={"steps": 12, "guidance": 1.5},
 )
 
@@ -106,7 +106,7 @@ from diffio import DiffioClient
 client = DiffioClient(apiKey="diffio_live_...")
 audio_bytes, info = client.restore_audio(
     filePath="sample.wav",
-    model="diffio-3.5",
+    model="diffio-4.0-flash",
     sampling={"steps": 12, "guidance": 1.5},
     onProgress=lambda progress: print(progress.status),
 )
diff --git a/src/diffio/__pycache__/__init__.cpython-312.pyc b/src/diffio/__pycache__/__init__.cpython-312.pyc
new file mode 100644
index 0000000..34d5e29
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diff --git a/src/diffio/__pycache__/client.cpython-312.pyc b/src/diffio/__pycache__/client.cpython-312.pyc
new file mode 100644
index 0000000..f8a093d
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diff --git a/src/diffio/__pycache__/errors.cpython-312.pyc b/src/diffio/__pycache__/errors.cpython-312.pyc
new file mode 100644
index 0000000..2e6daa5
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diff --git a/src/diffio/__pycache__/types.cpython-312.pyc b/src/diffio/__pycache__/types.cpython-312.pyc
new file mode 100644
index 0000000..3dca6ca
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diff --git a/src/diffio/client.py b/src/diffio/client.py
index 9a48da7..6a3c774 100644
--- a/src/diffio/client.py
+++ b/src/diffio/client.py
@@ -38,6 +38,8 @@
     "diffio-2-flash": "diffio-2.0-flash-generation",
     "diffio-3.4": "diffio-3.4-generation",
     "diffio-3.5": "diffio-3.5-generation",
+    "diffio-4.0-flash": "diffio-4.0-flash-generation",
+    "diffio-4.0-pro": "diffio-4.0-pro-generation",
 }
 DEFAULT_RETRY_STATUS_CODES = [408, 429, 500, 502, 503, 504]
 DEFAULT_RETRY_BACKOFF = 0.5
diff --git a/src/diffio/types.py b/src/diffio/types.py
index 227c7e3..14e8fba 100644
--- a/src/diffio/types.py
+++ b/src/diffio/types.py
@@ -451,7 +451,7 @@ def __init__(self, project, generation):
         self.generation = generation
 
 
-ModelKey = ("diffio-2", "diffio-2-flash", "diffio-3.4", "diffio-3.5")
+ModelKey = ("diffio-2", "diffio-2-flash", "diffio-3.4", "diffio-3.5", "diffio-4.0-flash", "diffio-4.0-pro")
 DownloadType = ("audio", "mp3", "video", "transcript")
 WebhookMode = ("test", "live")
 WebhookEventType = (
diff --git a/tests/__pycache__/conftest.cpython-312-pytest-9.1.1.pyc b/tests/__pycache__/conftest.cpython-312-pytest-9.1.1.pyc
new file mode 100644
index 0000000..40eb1a5
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diff --git a/tests/__pycache__/test_client.cpython-312-pytest-9.1.1.pyc b/tests/__pycache__/test_client.cpython-312-pytest-9.1.1.pyc
new file mode 100644
index 0000000..f591ca2
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diff --git a/tests/__pycache__/test_diffio40_models.cpython-312-pytest-9.1.1.pyc b/tests/__pycache__/test_diffio40_models.cpython-312-pytest-9.1.1.pyc
new file mode 100644
index 0000000..aadfaca
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diff --git a/tests/__pycache__/test_transcription.cpython-312-pytest-9.1.1.pyc b/tests/__pycache__/test_transcription.cpython-312-pytest-9.1.1.pyc
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index 0000000..38493d9
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diff --git a/tests/test_diffio40_models.py b/tests/test_diffio40_models.py
new file mode 100644
index 0000000..8484062
--- /dev/null
+++ b/tests/test_diffio40_models.py
@@ -0,0 +1,34 @@
+import json
+
+import httpx
+import pytest
+
+from diffio import DiffioClient
+
+
+@pytest.mark.parametrize(
+    ("model", "path"),
+    [
+        ("diffio-4.0-flash", "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/v1/diffio-4.0-flash-generation"),
+        ("diffio-4.0-pro", "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/v1/diffio-4.0-pro-generation"),
+    ],
+)
+def test_create_generation_routes_each_diffio_4_0_model_to_its_endpoint(model, path):
+    received = {}
+
+    def handler(request: httpx.Request) -> httpx.Response:
+        received["path"] = request.url.path
+        received["payload"] = json.loads(request.content.decode("utf-8"))
+        return httpx.Response(
+            200,
+            json={"generationId": "gen_40", "apiProjectId": "proj_40", "modelKey": model, "status": "queued"},
+        )
+
+    http_client = httpx.Client(base_url="https://api.test", transport=httpx.MockTransport(handler))
+    client = DiffioClient(apiKey="diffio_live_test", baseUrl="https://api.test", httpClient=http_client)
+
+    response = client.create_generation(apiProjectId="proj_40", model=model)
+
+    assert received["path"] == path
+    assert received["payload"]["apiProjectId"] == "proj_40"
+    assert response.modelKey == model