diff --git a/requirements-dev.txt b/requirements-dev.txt
index 35d47f31..844827fd 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -11,7 +11,7 @@ mypy
 pyyaml
 httpx
 fastapi
-pydantic
+pydantic==1.10.13
 numpy
 scipy
 boto3
diff --git a/tox.ini b/tox.ini
index f436345c..547a1a45 100644
--- a/tox.ini
+++ b/tox.ini
@@ -16,7 +16,7 @@ deps=
     mypy_boto3_s3
 extras=
     yaml
-    pydantic
+    pydantic<2
     flask
     aiohttp
 commands = pytest -c tests/.configs/pytest.ini
@@ -24,7 +24,7 @@ python_files = test_*_py3*.py
 
 [testenv:coveralls]
 passenv = GITHUB_*, COVERALLS_*
-basepython=python3.11
+basepython=python3.12
 usedevelop=True
 deps=
     {[testenv]deps}