diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index e022641e2c..78a78bb8c2 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -35,8 +35,7 @@ jobs:
         with:
           python-version: 3.11
       - name: Install Python dependencies
-        run: |
-          python -m pip install '.[dev]'
+        run: make install-python
       - name: Build
         run: make cog
       - name: Lint
@@ -60,8 +59,7 @@ jobs:
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install Python dependencies
-        run: |
-          python -m pip install '.[dev]'
+        run: make install-python
       - name: Test
         run: make test-python
         env:
@@ -79,11 +77,9 @@ jobs:
         with:
           python-version: "3.11"
       - name: Install Python dependencies
-        run: |
-          python -m pip install '.[dev]'
+        run: make install-python
       - name: Run typechecking
-        run: |
-          make lint-python
+        run: make lint-python
 
   # cannot run this on mac due to licensing issues: https://github.com/actions/virtual-environments/issues/2150
   test-integration:
@@ -98,8 +94,7 @@ jobs:
         with:
           python-version: 3.11
       - name: Install Python dependencies
-        run: |
-          python -m pip install '.[dev]'
+        run: make install-python
       - name: Test
         run: make test-integration
 
diff --git a/.gitignore b/.gitignore
index 4cde3813fc..998867f4ba 100644
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,4 @@ pkg/dockerfile/embed/cog.whl
 .DS_Store
 docs/README.md
 docs/CONTRIBUTING.md
+python/cog/_vendor/
\ No newline at end of file
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 39db059526..9a8dc38f39 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -207,6 +207,23 @@ To publish a prerelease version, append a [SemVer prerelease identifer](https://
     git tag -a v0.1.0-alpha -m "Prerelease v0.1.0"
     git push --tags
 
+## Vendoring Python packages
+
+We vendor the few Python libraries we depend on to avoid dependency hell. We use [vendoring](https://pypi.org/project/vendoring/), the same tool used by pip.
+
+The vendored packages are defined in `python/cog/_vendor/vendor.txt`. If you add/change anything in there, the default `make` rule will sync all vendored packages.
+
+If you run into issues you may need to manually add a patch. Patches are stored in `python/tools/vendoring/patches`.
+
+To create a new patch, copy the file you want to patch to `$FILENAME.new`, and edit that file as needed. For example:
+
+    cp python/cog/_vendor/curio/__main__.py python/cog/_vendor/curio/__main__.py.new
+
+Then `diff` the new and old version to a patch file in `python/tools/vendoring/patches/$PACKAGE.patch` and re-run vendoring. For example:
+
+    diff -u ./python/cog/_vendor/curio/__main__.py ./python/cog/_vendor/curio/__main__.py.new >> python/tools/vendoring/patches/curio.patch
+    make
+
 ## Troubleshooting
 
 ### `cog command not found`
diff --git a/Makefile b/Makefile
index 6e2a6a9018..a91cc83661 100644
--- a/Makefile
+++ b/Makefile
@@ -15,16 +15,21 @@ PYTHON ?= python
 PYTEST := $(PYTHON) -m pytest
 PYRIGHT := $(PYTHON) -m pyright
 RUFF := $(PYTHON) -m ruff
+PIP := $(PYTHON) -m pip
+VENDORING := $(PYTHON) -m vendoring
 
 default: all
 
 .PHONY: all
 all: cog
 
-pkg/dockerfile/embed/cog.whl: python/* python/cog/* python/cog/server/* python/cog/command/*
+python/cog/_vendor: python/cog/vendor.txt
+	$(VENDORING) sync
+
+pkg/dockerfile/embed/cog.whl: python/* python/cog/* python/cog/server/* python/cog/command/* python/cog/_vendor
 	@echo "Building Python library"
 	rm -rf dist
-	$(PYTHON) -m pip install build && $(PYTHON) -m build --wheel
+	$(PIP) install build && $(PYTHON) -m build --wheel
 	mkdir -p pkg/dockerfile/embed
 	cp dist/*.whl $@
 
@@ -68,7 +73,7 @@ test-integration: cog
 	cd test-integration/ && $(MAKE) PATH="$(PWD):$(PATH)" test
 
 .PHONY: test-python
-test-python:
+test-python: python/cog/_vendor
 	$(PYTEST) -n auto -vv --cov=python/cog  --cov-report term-missing  python/tests $(if $(FILTER),-k "$(FILTER)",)
 
 .PHONY: test
@@ -99,7 +104,7 @@ lint-go:
 	$(GO) run github.com/golangci/golangci-lint/cmd/golangci-lint run ./...
 
 .PHONY: lint-python
-lint-python:
+lint-python: python/cog/_vendor
 	$(RUFF) python/cog
 	$(RUFF) format --check python
 	@$(PYTHON) -c 'import sys; sys.exit("Warning: python >=3.10 is needed (not installed) to pass linting (pyright)") if sys.version_info < (3, 10) else None'
@@ -114,12 +119,12 @@ mod-tidy:
 
 .PHONY: install-python # install dev dependencies
 install-python:
-	$(PYTHON) -m pip install '.[dev]'
-
+	$(PIP) install '.[dev]'
+	$(PIP) install --no-deps --ignore-requires-python vendoring==1.2.0
 
 .PHONY: run-docs-server
 run-docs-server:
-	pip install mkdocs-material
+	$(PIP) install mkdocs-material
 	sed 's/docs\///g' README.md > ./docs/README.md
 	cp CONTRIBUTING.md ./docs/
 	mkdocs serve
diff --git a/pyproject.toml b/pyproject.toml
index a7438613bd..115dc17f69 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -12,22 +12,12 @@ urls."Source" = "https://github.com/replicate/cog"
 
 requires-python = ">=3.7"
 dependencies = [
-  # intentionally loose. perhaps these should be vendored to not collide with user code?
-  "attrs>=20.1,<24",
-  "fastapi>=0.75.2,<0.99.0",
-  "pydantic>=1.9,<2",
-  "PyYAML",
-  "requests>=2,<3",
-  "structlog>=20,<25",
   'typing-compat; python_version < "3.8"',
-  "typing_extensions>=4.4.0",
-  "uvicorn[standard]>=0.12,<1",
 ]
 
 optional-dependencies = { "dev" = [
   "black",
   "build",
-  "httpx",
   'hypothesis<6.80.0; python_version < "3.8"',
   'hypothesis; python_version >= "3.8"',
   'numpy<1.22.0; python_version < "3.8"',
@@ -41,6 +31,17 @@ optional-dependencies = { "dev" = [
   "pytest-cov",
   "responses",
   "ruff",
+
+  # vendoring's dependencies are listed below. vendoring is pinned to
+  # python 3.8 and you can't specify --no-deps or
+  # --ignore-requires-python in pyproject.toml, so unfortunately we
+  # have to install vendoring in the Makefile.
+  "click",
+  "jsonschema",
+  "packaging",
+  "requests",
+  "rich",
+  "toml",
 ] }
 
 dynamic = ["version"]
@@ -54,7 +55,7 @@ strictParameterNoneValue = false
 # legacy behavior, fixed in PEP688
 disableBytesTypePromotions = true
 include = ["python"]
-exclude = ["python/tests"]
+exclude = ["python/tests", "python/cog/_vendor", "python/build"]
 reportMissingParameterType = "error"
 reportUnknownLambdaType = "error"
 reportUnnecessaryIsInstance = "warning"
@@ -92,6 +93,7 @@ ignore = [
 extend-exclude = [
   "python/tests/server/fixtures/*",
   "test-integration/test_integration/fixtures/*",
+  "python/cog/_vendor/*",
 ]
 
 [tool.ruff.per-file-ignores]
@@ -111,3 +113,42 @@ extend-exclude = [
   "S607", # Starting a process with a partial executable path"
   "ANN",
 ]
+
+[tool.black]
+exclude = '(\.eggs|\.git|\.hg|\.mypy|_cache|\.nox|\.tox|\.venv|\.svn|_build|buck-out|build|dist|_vendor)'
+
+[tool.vendoring]
+destination = "python/cog/_vendor/"
+requirements = "python/cog/vendor.txt"
+namespace = "cog._vendor"
+
+protected-files = ["__init__.py", "README.rst", "vendor.txt"]
+patches-dir = "python/tools/vendoring/patches"
+
+[tool.vendoring.transformations]
+substitute = []
+drop = [
+  # we won't run any dependencies as scripts
+  "bin/",
+
+  # pydantic falls back to plain python
+  "pydantic/*.so",
+
+  # pyyaml falls back to plain python
+  "_yaml.*.so",
+
+  # sniffio ships with tests
+  "sniffio/_tests",
+
+  # h11 ships with tests
+  "h11/tests",
+
+  # pydantic hypothesis plugin, fall back to python
+  "pydantic/_hypothesis_plugin.*.so",
+]
+
+[tool.vendoring.typing-stubs]
+
+[tool.vendoring.license.directories]
+
+[tool.vendoring.license.fallback-urls]
\ No newline at end of file
diff --git a/python/cog/__init__.py b/python/cog/__init__.py
index b8371e0f09..01d875ab71 100644
--- a/python/cog/__init__.py
+++ b/python/cog/__init__.py
@@ -1,5 +1,4 @@
-from pydantic import BaseModel
-
+from ._vendor.pydantic import BaseModel
 from .predictor import BasePredictor
 from .types import ConcatenateIterator, File, Input, Path, Secret
 
diff --git a/python/cog/files.py b/python/cog/files.py
index 2ca8cd383a..9a010e1bdb 100644
--- a/python/cog/files.py
+++ b/python/cog/files.py
@@ -4,7 +4,7 @@
 import os
 from urllib.parse import urlparse
 
-import requests
+from ._vendor import requests
 
 
 def upload_file(fh: io.IOBase, output_file_prefix: str = None) -> str:
diff --git a/python/cog/json.py b/python/cog/json.py
index 843572eea0..2b9e56eb3a 100644
--- a/python/cog/json.py
+++ b/python/cog/json.py
@@ -4,8 +4,7 @@
 from types import GeneratorType
 from typing import Any, Callable
 
-from pydantic import BaseModel
-
+from ._vendor.pydantic import BaseModel
 from .types import Path
 
 
diff --git a/python/cog/logging.py b/python/cog/logging.py
index 7b25214543..934170cb81 100644
--- a/python/cog/logging.py
+++ b/python/cog/logging.py
@@ -1,8 +1,8 @@
 import logging
 import os
 
-import structlog
-from structlog.typing import EventDict
+from ._vendor import structlog
+from ._vendor.structlog.typing import EventDict
 
 
 def replace_level_with_severity(
diff --git a/python/cog/predictor.py b/python/cog/predictor.py
index 46f6920d20..3db5f58f17 100644
--- a/python/cog/predictor.py
+++ b/python/cog/predictor.py
@@ -21,22 +21,21 @@
 )
 from unittest.mock import patch
 
-import structlog
-
 import cog.code_xforms as code_xforms
 
+from ._vendor import structlog
+from ._vendor.typing_extensions import Annotated
+
 try:
     from typing import get_args, get_origin
 except ImportError:  # Python < 3.8
     from typing_compat import get_args, get_origin  # type: ignore
 
-import yaml
-from pydantic import BaseModel, Field, create_model
-from pydantic.fields import FieldInfo
+from ._vendor import yaml
+from ._vendor.pydantic import BaseModel, Field, create_model
+from ._vendor.pydantic.fields import FieldInfo
 
 # Added in Python 3.9. Can be from typing if we drop support for <3.9
-from typing_extensions import Annotated
-
 from .errors import ConfigDoesNotExist, PredictorNotSet
 from .types import (
     File as CogFile,
@@ -158,7 +157,7 @@ def load_config() -> Dict[str, Any]:
     config_path = os.path.abspath("cog.yaml")
     try:
         with open(config_path) as fh:
-            config = yaml.safe_load(fh)
+            config: Dict[str, Any] = yaml.safe_load(fh)  # type: ignore
     except FileNotFoundError as e:
         raise ConfigDoesNotExist(
             f"Could not find {config_path}",
diff --git a/python/cog/schema.py b/python/cog/schema.py
index 508c1f0f12..c7de412520 100644
--- a/python/cog/schema.py
+++ b/python/cog/schema.py
@@ -7,7 +7,7 @@
 from enum import Enum
 from types import ModuleType
 
-import pydantic
+from ._vendor import pydantic
 
 BUNDLED_SCHEMA_PATH = ".cog/schema.py"
 
diff --git a/python/cog/server/eventtypes.py b/python/cog/server/eventtypes.py
index 4f9a6643a5..b333e47542 100644
--- a/python/cog/server/eventtypes.py
+++ b/python/cog/server/eventtypes.py
@@ -1,6 +1,6 @@
 from typing import Any, Dict
 
-from attrs import define, field, validators
+from .._vendor.attrs import define, field, validators
 
 
 # From worker parent process
diff --git a/python/cog/server/http.py b/python/cog/server/http.py
index 0a2be6aaf6..ae209622ee 100644
--- a/python/cog/server/http.py
+++ b/python/cog/server/http.py
@@ -25,17 +25,14 @@
 if TYPE_CHECKING:
     from typing import ParamSpec
 
-import attrs
-import structlog
-import uvicorn
-from fastapi import Body, FastAPI, Header, HTTPException, Path, Response
-from fastapi.encoders import jsonable_encoder
-from fastapi.exceptions import RequestValidationError
-from fastapi.responses import JSONResponse
-from pydantic import ValidationError
-from pydantic.error_wrappers import ErrorWrapper
-
 from .. import schema
+from .._vendor import attrs, structlog, uvicorn
+from .._vendor.fastapi import Body, FastAPI, Header, HTTPException, Path, Response
+from .._vendor.fastapi.encoders import jsonable_encoder
+from .._vendor.fastapi.exceptions import RequestValidationError
+from .._vendor.fastapi.responses import JSONResponse
+from .._vendor.pydantic import ValidationError
+from .._vendor.pydantic.error_wrappers import ErrorWrapper
 from ..errors import PredictorNotSet
 from ..files import upload_file
 from ..json import upload_files
@@ -296,7 +293,7 @@ async def predict_idempotent(
                             "prediction ID must match the ID supplied in the URL"
                         ),
                         ("body", "id"),
-                    )
+                    )  # type: ignore
                 ]
             )
 
@@ -310,7 +307,7 @@ async def predict_idempotent(
         return _predict(request=request, respond_async=respond_async)
 
     def _predict(
-        *, request: PredictionRequest, respond_async: bool = False
+        *, request: Optional[PredictionRequest], respond_async: bool = False
     ) -> Response:
         # [compat] If no body is supplied, assume that this model can be run
         # with empty input. This will throw a ValidationError if that's not
diff --git a/python/cog/server/runner.py b/python/cog/server/runner.py
index 54e1360901..ffa3bba33a 100644
--- a/python/cog/server/runner.py
+++ b/python/cog/server/runner.py
@@ -7,14 +7,12 @@
 from multiprocessing.pool import AsyncResult, ThreadPool
 from typing import Any, Callable, Optional, Tuple, Union, cast
 
-import requests
-import structlog
-from attrs import define
-from fastapi.encoders import jsonable_encoder
-from requests.adapters import HTTPAdapter
-from requests.packages.urllib3.util.retry import Retry  # type: ignore
-
 from .. import schema, types
+from .._vendor import requests, structlog
+from .._vendor.attrs import define
+from .._vendor.fastapi.encoders import jsonable_encoder
+from .._vendor.requests.adapters import HTTPAdapter
+from .._vendor.urllib3.util.retry import Retry  # type: ignore
 from ..files import put_file_to_signed_endpoint
 from ..json import upload_files
 from .eventtypes import Done, Heartbeat, Log, PredictionOutput, PredictionOutputType
@@ -454,7 +452,7 @@ def _make_file_upload_http_client() -> requests.Session:
             backoff_factor=0.1,
             status_forcelist=[408, 429, 500, 502, 503, 504],
             allowed_methods=["PUT"],
-        ),
+        ),  # type: ignore
     )
     session.mount("http://", adapter)
     session.mount("https://", adapter)
diff --git a/python/cog/server/webhook.py b/python/cog/server/webhook.py
index d71cf81e25..6ad961b37b 100644
--- a/python/cog/server/webhook.py
+++ b/python/cog/server/webhook.py
@@ -1,11 +1,9 @@
 import os
 from typing import Any, Callable, Set
 
-import requests
-import structlog
-from requests.adapters import HTTPAdapter
-from requests.packages.urllib3.util.retry import Retry  # type: ignore
-
+from .._vendor import requests, structlog
+from .._vendor.requests.adapters import HTTPAdapter
+from .._vendor.urllib3.util.retry import Retry  # type: ignore
 from ..schema import Status, WebhookEvent
 from .response_throttler import ResponseThrottler
 
@@ -96,7 +94,7 @@ def requests_session_with_retries() -> requests.Session:
             backoff_factor=0.1,
             status_forcelist=[429, 500, 502, 503, 504],
             allowed_methods=["POST"],
-        )
+        )  # type: ignore
     )
     session.mount("http://", adapter)
     session.mount("https://", adapter)
diff --git a/python/cog/types.py b/python/cog/types.py
index a75b48d99b..e6d5b88e2f 100644
--- a/python/cog/types.py
+++ b/python/cog/types.py
@@ -8,8 +8,8 @@
 import urllib.request
 from typing import Any, Dict, Iterator, List, Optional, TypeVar, Union
 
-import requests
-from pydantic import Field, SecretStr
+from ._vendor import requests
+from ._vendor.pydantic import Field, SecretStr
 
 FILENAME_ILLEGAL_CHARS = set("\u0000/")
 
diff --git a/python/cog/vendor.txt b/python/cog/vendor.txt
new file mode 100644
index 0000000000..5da9d8b03c
--- /dev/null
+++ b/python/cog/vendor.txt
@@ -0,0 +1,27 @@
+attrs==23.2.0
+fastapi==0.98.0
+    starlette==0.27.0
+    httpcore==0.17.3
+    anyio==3.7.1
+    httpx==0.24.1
+    sniffio==1.3.1
+pydantic==1.10.15
+PyYAML==6.0.1
+requests==2.31.0
+    certifi==2024.2.2
+    charset-normalizer==3.3.2
+    urllib3==2.0.7
+structlog==23.1.0
+typing_extensions==4.7.1
+uvicorn[standard]==0.22.0
+    h11==0.14.0
+    click==8.1.7
+    exceptiongroup==1.2.0
+    zipp==3.15.0
+    idna==3.7
+    importlib-metadata==6.7.0
+    python-dotenv==0.21.1
+    httptools==0.6.0
+    websockets==11.0.3
+    watchfiles==0.20.0
+    uvloop==0.18.0
diff --git a/python/tests/server/conftest.py b/python/tests/server/conftest.py
index b332c87c15..56eaccb5bf 100644
--- a/python/tests/server/conftest.py
+++ b/python/tests/server/conftest.py
@@ -6,10 +6,10 @@
 from unittest import mock
 
 import pytest
-from attrs import define
+from cog._vendor.attrs import define
 from cog.command import ast_openapi_schema
 from cog.server.http import create_app
-from fastapi.testclient import TestClient
+from cog._vendor.fastapi.testclient import TestClient
 
 
 @define
diff --git a/python/tests/server/fixtures/complex_output.py b/python/tests/server/fixtures/complex_output.py
index 3be75bd2a6..db0f6fdfaa 100644
--- a/python/tests/server/fixtures/complex_output.py
+++ b/python/tests/server/fixtures/complex_output.py
@@ -1,4 +1,4 @@
-from pydantic import BaseModel
+from cog import BaseModel
 
 
 class Output(BaseModel):
diff --git a/python/tests/server/fixtures/input_unsupported_type.py b/python/tests/server/fixtures/input_unsupported_type.py
index 10518d659f..f33f1564e6 100644
--- a/python/tests/server/fixtures/input_unsupported_type.py
+++ b/python/tests/server/fixtures/input_unsupported_type.py
@@ -1,5 +1,4 @@
-from cog import BasePredictor
-from pydantic import BaseModel
+from cog import BasePredictor, BaseModel
 
 
 class Input(BaseModel):
diff --git a/python/tests/server/fixtures/openapi_custom_output_type.py b/python/tests/server/fixtures/openapi_custom_output_type.py
index f04ed1e5ea..ed90ebeee4 100644
--- a/python/tests/server/fixtures/openapi_custom_output_type.py
+++ b/python/tests/server/fixtures/openapi_custom_output_type.py
@@ -1,5 +1,4 @@
-from cog import BasePredictor
-from pydantic import BaseModel
+from cog import BasePredictor, BaseModel
 
 
 # Calling this `MyOutput` to test if cog renames it to `Output` in the schema
diff --git a/python/tests/server/fixtures/openapi_output_type.py b/python/tests/server/fixtures/openapi_output_type.py
index a22d6aa2f8..3df784d179 100644
--- a/python/tests/server/fixtures/openapi_output_type.py
+++ b/python/tests/server/fixtures/openapi_output_type.py
@@ -1,5 +1,4 @@
-from cog import BasePredictor
-from pydantic import BaseModel
+from cog import BasePredictor, BaseModel
 
 
 # An output object called `Output` needs to be special cased because pydantic tries to dedupe it with the internal `Output`
diff --git a/python/tests/server/fixtures/output_complex.py b/python/tests/server/fixtures/output_complex.py
index 0a38809114..74c2bcca41 100644
--- a/python/tests/server/fixtures/output_complex.py
+++ b/python/tests/server/fixtures/output_complex.py
@@ -1,7 +1,6 @@
 import io
 
-from cog import BasePredictor, File
-from pydantic import BaseModel
+from cog import BasePredictor, File, BaseModel
 
 
 class Output(BaseModel):
diff --git a/python/tests/server/fixtures/output_iterator_complex.py b/python/tests/server/fixtures/output_iterator_complex.py
index 737093a628..030a4998aa 100644
--- a/python/tests/server/fixtures/output_iterator_complex.py
+++ b/python/tests/server/fixtures/output_iterator_complex.py
@@ -1,7 +1,6 @@
 from typing import Iterator, List
 
-from cog import BasePredictor
-from pydantic import BaseModel
+from cog import BasePredictor, BaseModel
 
 
 class Output(BaseModel):
diff --git a/python/tests/server/test_http_input.py b/python/tests/server/test_http_input.py
index a64bb0104f..16cf548f3b 100644
--- a/python/tests/server/test_http_input.py
+++ b/python/tests/server/test_http_input.py
@@ -10,6 +10,8 @@
 
 from .conftest import uses_predictor
 
+responses.mock.target = "cog._vendor.requests.adapters.HTTPAdapter.send"
+
 
 @uses_predictor("input_none")
 def test_no_input(client, match):
diff --git a/python/tests/server/test_http_output.py b/python/tests/server/test_http_output.py
index 281134cf9e..534dcf49b1 100644
--- a/python/tests/server/test_http_output.py
+++ b/python/tests/server/test_http_output.py
@@ -6,6 +6,8 @@
 
 from .conftest import uses_predictor, uses_predictor_with_client_options
 
+responses.mock.target = "cog._vendor.requests.adapters.HTTPAdapter.send"
+
 
 @uses_predictor("output_wrong_type")
 def test_return_wrong_type(client):
diff --git a/python/tests/server/test_webhook.py b/python/tests/server/test_webhook.py
index 8a6bfb8543..9f2a102aab 100644
--- a/python/tests/server/test_webhook.py
+++ b/python/tests/server/test_webhook.py
@@ -1,4 +1,4 @@
-import requests
+from cog._vendor import requests
 import responses
 from cog.schema import WebhookEvent
 from cog.server.webhook import webhook_caller, webhook_caller_filtered
diff --git a/python/tests/server/test_worker.py b/python/tests/server/test_worker.py
index 2895e0c81f..0cdd5b970e 100644
--- a/python/tests/server/test_worker.py
+++ b/python/tests/server/test_worker.py
@@ -3,7 +3,7 @@
 from typing import Any, Optional
 
 import pytest
-from attrs import define
+from cog._vendor.attrs import define
 from cog.server.eventtypes import (
     Done,
     Heartbeat,
diff --git a/python/tests/test_json.py b/python/tests/test_json.py
index 6311e34be1..7adefba870 100644
--- a/python/tests/test_json.py
+++ b/python/tests/test_json.py
@@ -5,7 +5,7 @@
 import numpy as np
 from cog.files import upload_file
 from cog.json import make_encodeable, upload_files
-from pydantic import BaseModel
+from cog._vendor.pydantic import BaseModel
 
 
 def test_make_encodeable_recursively_encodes_tuples():
diff --git a/python/tools/vendoring/patches/anyio.patch b/python/tools/vendoring/patches/anyio.patch
new file mode 100644
index 0000000000..52e70232e4
--- /dev/null
+++ b/python/tools/vendoring/patches/anyio.patch
@@ -0,0 +1,20 @@
+--- ./python/cog/_vendor/anyio/_core/_eventloop.py	2024-04-16 13:10:15
++++ ./python/cog/_vendor/anyio/_core/_eventloop.py.new	2024-04-16 13:11:09
+@@ -134,7 +134,7 @@
+ 
+ @contextmanager
+ def claim_worker_thread(backend: str) -> Generator[Any, None, None]:
+-    module = sys.modules["anyio._backends._" + backend]
++    module = sys.modules["cog._vendor.anyio._backends._" + backend]
+     threadlocals.current_async_module = module
+     try:
+         yield
+@@ -146,7 +146,7 @@
+     if asynclib_name is None:
+         asynclib_name = sniffio.current_async_library()
+ 
+-    modulename = "anyio._backends._" + asynclib_name
++    modulename = "cog._vendor.anyio._backends._" + asynclib_name
+     try:
+         return sys.modules[modulename]
+     except KeyError:
diff --git a/python/tools/vendoring/patches/certifi.patch b/python/tools/vendoring/patches/certifi.patch
new file mode 100644
index 0000000000..09e9168e8a
--- /dev/null
+++ b/python/tools/vendoring/patches/certifi.patch
@@ -0,0 +1,42 @@
+--- ./python/cog/_vendor/certifi/core.py	2024-04-15 18:08:25
++++ ./python/cog/_vendor/certifi/core.py.new	2024-04-15 18:21:12
+@@ -37,14 +37,14 @@
+             # We also have to hold onto the actual context manager, because
+             # it will do the cleanup whenever it gets garbage collected, so
+             # we will also store that at the global level as well.
+-            _CACERT_CTX = as_file(files("certifi").joinpath("cacert.pem"))
++            _CACERT_CTX = as_file(files("cog._vendor.certifi").joinpath("cacert.pem"))
+             _CACERT_PATH = str(_CACERT_CTX.__enter__())
+             atexit.register(exit_cacert_ctx)
+ 
+         return _CACERT_PATH
+ 
+     def contents() -> str:
+-        return files("certifi").joinpath("cacert.pem").read_text(encoding="ascii")
++        return files("cog._vendor.certifi").joinpath("cacert.pem").read_text(encoding="ascii")
+ 
+ elif sys.version_info >= (3, 7):
+ 
+@@ -73,14 +73,14 @@
+             # We also have to hold onto the actual context manager, because
+             # it will do the cleanup whenever it gets garbage collected, so
+             # we will also store that at the global level as well.
+-            _CACERT_CTX = get_path("certifi", "cacert.pem")
++            _CACERT_CTX = get_path("cog._vendor.certifi", "cacert.pem")
+             _CACERT_PATH = str(_CACERT_CTX.__enter__())
+             atexit.register(exit_cacert_ctx)
+ 
+         return _CACERT_PATH
+ 
+     def contents() -> str:
+-        return read_text("certifi", "cacert.pem", encoding="ascii")
++        return read_text("cog._vendor.certifi", "cacert.pem", encoding="ascii")
+ 
+ else:
+     import os
+@@ -111,4 +111,4 @@
+         return os.path.join(f, "cacert.pem")
+ 
+     def contents() -> str:
+-        return read_text("certifi", "cacert.pem", encoding="ascii")
++        return read_text("cog._vendor.certifi", "cacert.pem", encoding="ascii")
diff --git a/python/tools/vendoring/patches/pydantic.patch b/python/tools/vendoring/patches/pydantic.patch
new file mode 100644
index 0000000000..0fd5d700c3
--- /dev/null
+++ b/python/tools/vendoring/patches/pydantic.patch
@@ -0,0 +1,96 @@
+--- ./python/cog/_vendor/pydantic/_hypothesis_plugin.py	2024-04-15 16:14:31
++++ ./python/cog/_vendor/pydantic/_hypothesis_plugin.py.new	2024-04-15 16:16:29
+@@ -33,8 +33,8 @@
+ import hypothesis.strategies as st
+ 
+ import pydantic
+-import pydantic.color
+-import pydantic.types
++import pydantic.color as pydantic_color
++import pydantic.types as pydantic_types
+ from pydantic.utils import lenient_issubclass
+ 
+ # FilePath and DirectoryPath are explicitly unsupported, as we'd have to create
+@@ -88,23 +88,23 @@
+ _color_regexes = (
+     '|'.join(
+         (
+-            pydantic.color.r_hex_short,
+-            pydantic.color.r_hex_long,
+-            pydantic.color.r_rgb,
+-            pydantic.color.r_rgba,
+-            pydantic.color.r_hsl,
+-            pydantic.color.r_hsla,
++            pydantic_color.r_hex_short,
++            pydantic_color.r_hex_long,
++            pydantic_color.r_rgb,
++            pydantic_color.r_rgba,
++            pydantic_color.r_hsl,
++            pydantic_color.r_hsla,
+         )
+     )
+     # Use more precise regex patterns to avoid value-out-of-range errors
+-    .replace(pydantic.color._r_sl, r'(?:(\d\d?(?:\.\d+)?|100(?:\.0+)?)%)')
+-    .replace(pydantic.color._r_alpha, r'(?:(0(?:\.\d+)?|1(?:\.0+)?|\.\d+|\d{1,2}%))')
+-    .replace(pydantic.color._r_255, r'(?:((?:\d|\d\d|[01]\d\d|2[0-4]\d|25[0-4])(?:\.\d+)?|255(?:\.0+)?))')
++    .replace(pydantic_color._r_sl, r'(?:(\d\d?(?:\.\d+)?|100(?:\.0+)?)%)')
++    .replace(pydantic_color._r_alpha, r'(?:(0(?:\.\d+)?|1(?:\.0+)?|\.\d+|\d{1,2}%))')
++    .replace(pydantic_color._r_255, r'(?:((?:\d|\d\d|[01]\d\d|2[0-4]\d|25[0-4])(?:\.\d+)?|255(?:\.0+)?))')
+ )
+ st.register_type_strategy(
+-    pydantic.color.Color,
++    pydantic_color.Color,
+     st.one_of(
+-        st.sampled_from(sorted(pydantic.color.COLORS_BY_NAME)),
++        st.sampled_from(sorted(pydantic_color.COLORS_BY_NAME)),
+         st.tuples(
+             st.integers(0, 255),
+             st.integers(0, 255),
+@@ -182,22 +182,22 @@
+ 
+ 
+ @overload
+-def _registered(typ: Type[pydantic.types.T]) -> Type[pydantic.types.T]:
++def _registered(typ: Type[pydantic_types.T]) -> Type[pydantic_types.T]:
+     pass
+ 
+ 
+ @overload
+-def _registered(typ: pydantic.types.ConstrainedNumberMeta) -> pydantic.types.ConstrainedNumberMeta:
++def _registered(typ: pydantic_types.ConstrainedNumberMeta) -> pydantic_types.ConstrainedNumberMeta:
+     pass
+ 
+ 
+ def _registered(
+-    typ: Union[Type[pydantic.types.T], pydantic.types.ConstrainedNumberMeta]
+-) -> Union[Type[pydantic.types.T], pydantic.types.ConstrainedNumberMeta]:
+-    # This function replaces the version in `pydantic.types`, in order to
++    typ: Union[Type[pydantic_types.T], pydantic_types.ConstrainedNumberMeta]
++) -> Union[Type[pydantic_types.T], pydantic_types.ConstrainedNumberMeta]:
++    # This function replaces the version in `pydantic_types`, in order to
+     # effect the registration of new constrained types so that Hypothesis
+     # can generate valid examples.
+-    pydantic.types._DEFINED_TYPES.add(typ)
++    pydantic_types._DEFINED_TYPES.add(typ)
+     for supertype, resolver in RESOLVERS.items():
+         if issubclass(typ, supertype):
+             st.register_type_strategy(typ, resolver(typ))  # type: ignore
+@@ -206,7 +206,7 @@
+ 
+ 
+ def resolves(
+-    typ: Union[type, pydantic.types.ConstrainedNumberMeta]
++    typ: Union[type, pydantic_types.ConstrainedNumberMeta]
+ ) -> Callable[[Callable[..., st.SearchStrategy]], Callable[..., st.SearchStrategy]]:  # type: ignore[type-arg]
+     def inner(f):  # type: ignore
+         assert f not in RESOLVERS
+@@ -385,7 +385,7 @@
+ 
+ 
+ # Finally, register all previously-defined types, and patch in our new function
+-for typ in list(pydantic.types._DEFINED_TYPES):
++for typ in list(pydantic_types._DEFINED_TYPES):
+     _registered(typ)
+-pydantic.types._registered = _registered
++pydantic_types._registered = _registered
+ st.register_type_strategy(pydantic.Json, resolve_json)
diff --git a/python/tools/vendoring/patches/requests.patch b/python/tools/vendoring/patches/requests.patch
new file mode 100644
index 0000000000..7b32e8c340
--- /dev/null
+++ b/python/tools/vendoring/patches/requests.patch
@@ -0,0 +1,39 @@
+--- ./python/cog/_vendor/requests/packages.py	2024-04-15 18:07:15
++++ ./python/cog/_vendor/requests/packages.py.new	2024-04-15 18:08:05
+@@ -1,28 +1,20 @@
+ import sys
+ 
+-try:
+-    import chardet
+-except ImportError:
+-    import warnings
++import warnings
++from cog._vendor import charset_normalizer as chardet
++warnings.filterwarnings("ignore", "Trying to detect", module="charset_normalizer")
+ 
+-    import charset_normalizer as chardet
+-
+-    warnings.filterwarnings("ignore", "Trying to detect", module="charset_normalizer")
+-
+ # This code exists for backwards compatibility reasons.
+ # I don't like it either. Just look the other way. :)
+ 
+ for package in ("urllib3", "idna"):
+-    locals()[package] = __import__(package)
++    vendored_package = "cog._vendor." + package
++    locals()[package] = __import__(vendored_package)
+     # This traversal is apparently necessary such that the identities are
+     # preserved (requests.packages.urllib3.* is urllib3.*)
+     for mod in list(sys.modules):
+-        if mod == package or mod.startswith(f"{package}."):
+-            sys.modules[f"requests.packages.{mod}"] = sys.modules[mod]
++        if mod == vendored_package or mod.startswith(vendored_package + '.'):
++            unprefixed_mod = mod[len("cog._vendor."):]
++            sys.modules['cog._vendor.requests.packages.' + unprefixed_mod] = sys.modules[mod]
+ 
+-target = chardet.__name__
+-for mod in list(sys.modules):
+-    if mod == target or mod.startswith(f"{target}."):
+-        target = target.replace(target, "chardet")
+-        sys.modules[f"requests.packages.{target}"] = sys.modules[mod]
+ # Kinda cool, though, right?
diff --git a/python/tools/vendoring/patches/starlette.patch b/python/tools/vendoring/patches/starlette.patch
new file mode 100644
index 0000000000..18463cf109
--- /dev/null
+++ b/python/tools/vendoring/patches/starlette.patch
@@ -0,0 +1,29 @@
+--- ./python/cog/_vendor/starlette/testclient.py	2023-04-17 13:38:36
++++ ./python/cog/_vendor/starlette/testclient.py	2023-04-17 13:45:59
+@@ -12,7 +12,7 @@
+ from urllib.parse import unquote, urljoin
+ 
+ import anyio
+-import anyio.from_thread
++import anyio.from_thread as from_thread
+ import httpx
+ from anyio.streams.stapled import StapledObjectStream
+ 
+@@ -410,7 +410,7 @@
+         if self.portal is not None:
+             yield self.portal
+         else:
+-            with anyio.from_thread.start_blocking_portal(
++            with from_thread.start_blocking_portal(
+                 **self.async_backend
+             ) as portal:
+                 yield portal
+@@ -728,7 +728,7 @@
+     def __enter__(self) -> "TestClient":
+         with contextlib.ExitStack() as stack:
+             self.portal = portal = stack.enter_context(
+-                anyio.from_thread.start_blocking_portal(**self.async_backend)
++                from_thread.start_blocking_portal(**self.async_backend)
+             )
+ 
+             @stack.callback
diff --git a/python/tools/vendoring/patches/urllib3.patch b/python/tools/vendoring/patches/urllib3.patch
new file mode 100644
index 0000000000..c881a036a3
--- /dev/null
+++ b/python/tools/vendoring/patches/urllib3.patch
@@ -0,0 +1,29 @@
+diff --git a/python/cog/_vendor/urllib3/contrib/securetransport.py b/python/cog/_vendor/urllib3/contrib/securetransport.py
+index b97555454..189132baa 100644
+--- a/python/cog/_vendor/urllib3/contrib/securetransport.py
++++ b/python/cog/_vendor/urllib3/contrib/securetransport.py
+@@ -19,8 +19,8 @@
+
+ To use this module, simply import and inject it::
+
+-    import urllib3.contrib.securetransport
+-    urllib3.contrib.securetransport.inject_into_urllib3()
++    import urllib3.contrib.securetransport as securetransport
++    securetransport.inject_into_urllib3()
+
+ Happy TLSing!
+
+diff --git a/python/cog/_vendor/urllib3/contrib/pyopenssl.py b/python/cog/_vendor/urllib3/contrib/pyopenssl.py
+index c43146279..4cded53f6 100644
+--- a/python/cog/_vendor/urllib3/contrib/pyopenssl.py
++++ b/python/cog/_vendor/urllib3/contrib/pyopenssl.py
+@@ -28,7 +28,7 @@
+ .. code-block:: python
+
+     try:
+-        import urllib3.contrib.pyopenssl
+-        urllib3.contrib.pyopenssl.inject_into_urllib3()
++        import urllib3.contrib.pyopenssl as pyopenssl
++        pyopenssl.inject_into_urllib3()
+     except ImportError:
+         pass
diff --git a/python/tools/vendoring/patches/uvicorn.patch b/python/tools/vendoring/patches/uvicorn.patch
new file mode 100644
index 0000000000..51e557c1ee
--- /dev/null
+++ b/python/tools/vendoring/patches/uvicorn.patch
@@ -0,0 +1,13 @@
+--- ./python/cog/_vendor/uvicorn/importer.py	2024-04-15 21:38:17
++++ ./python/cog/_vendor/uvicorn/importer.py.new	2024-04-15 21:41:46
+@@ -18,6 +18,10 @@
+         raise ImportFromStringError(message.format(import_str=import_str))
+ 
+     try:
++        if module_str == "uvicorn":
++            module_str = "cog._vendor.uvicorn"
++        if module_str.startswith("uvicorn."):
++            module_str = "cog._vendor.uvicorn." + module_str.split("uvicorn.", 1)[1]
+         module = importlib.import_module(module_str)
+     except ImportError as exc:
+         if exc.name != module_str:
diff --git a/test-integration/test_integration/fixtures/complex_output_project/predict.py b/test-integration/test_integration/fixtures/complex_output_project/predict.py
index b1fb8d0e14..2076d83691 100644
--- a/test-integration/test_integration/fixtures/complex_output_project/predict.py
+++ b/test-integration/test_integration/fixtures/complex_output_project/predict.py
@@ -1,8 +1,7 @@
 import io
 
-from cog import BasePredictor, Path
+from cog import BasePredictor, Path, BaseModel
 from typing import Optional
-from pydantic import BaseModel
 
 
 class ModelOutput(BaseModel):