diff --git a/docs/changelog.md b/docs/changelog.md
index 98bee96..0c42fde 100644
--- a/docs/changelog.md
+++ b/docs/changelog.md
@@ -12,6 +12,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Removed
 - `STYLE_STRING_FORMAT_REGEX`, which is no longer used to find `{` style fields. [#75](https://github.com/nhairs/python-json-logger/pull/75)
 
+### Changed
+- Replaced MyPy with Pyrefly for type checking
+
 ### Fixed
 - `%` style formats no longer treat the escaped literal `%%` as the start of a field, so `"%%(notafield)s"` is correctly read as literal text. [#75](https://github.com/nhairs/python-json-logger/pull/75)
 - `{` style formats now use `string.Formatter` (as `logging.StrFormatStyle.validate` does) to find fields, so escaped literal braces (`{{`/`}}`) are skipped and a conversion (`{message!r}`) or format spec (`{levelname:>8}`) is no longer treated as part of the field name. [#75](https://github.com/nhairs/python-json-logger/pull/75)
diff --git a/docs/contributing.md b/docs/contributing.md
index 1994477..2a98ef6 100644
--- a/docs/contributing.md
+++ b/docs/contributing.md
@@ -47,13 +47,13 @@ black src tests
 
 # Lint
 pylint --output-format=colorized src
-mypy src tests
+pyrefly check src tests
 
 # Tests
 pytest
 ```
 
-The above commands (`black`, `pylint`, `mypy`, `pytest`) should all be run before submitting a pull request.
+The above commands (`black`, `pylint`, `pyrefly `, `pytest`) should all be run before submitting a pull request.
 
 If making changes to the documentation you can preview the changes locally using `mkdocs`. Changes to the `README.md` can be previewed using a tool like [`grip`](https://github.com/joeyespo/grip) (installable via `pip install grip`).
 
diff --git a/docs/style-guide.md b/docs/style-guide.md
index ab217c5..a925b23 100644
--- a/docs/style-guide.md
+++ b/docs/style-guide.md
@@ -15,9 +15,9 @@ We use automated tools to enforce a consistent code style and catch potential er
 
 *   **Black:** For opinionated code formatting.
 *   **Pylint:** For static code analysis and error detection.
-*   **MyPy:** For static type checking.
+*   **Pyrefly:** For static type checking.
 
-Ensure these tools are run before committing code. Configuration for these tools can be found in `pyproject.toml`, `pylintrc`, and `mypy.ini` respectively. This guide primarily focuses on conventions not automatically verifiable by these tools.
+Ensure these tools are run before committing code. Configuration for these tools can be found in `pyproject.toml`, `pylintrc`, and `pyrefly.toml` respectively. This guide primarily focuses on conventions not automatically verifiable by these tools.
 
 ## Imports
 
diff --git a/mypy.ini b/mypy.ini
deleted file mode 100644
index f8b1844..0000000
--- a/mypy.ini
+++ /dev/null
@@ -1 +0,0 @@
-[mypy]
diff --git a/pyproject.toml b/pyproject.toml
index e9f4714..db24d60 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -49,8 +49,7 @@ dev = [
     "validate-pyproject[all]",
     "black",
     "pylint",
-    "mypy<2; implementation_name == 'pypy' and python_version < '3.11'",
-    "mypy; implementation_name != 'pypy' or python_version >= '3.11'",
+    "pyrefly",
     ## Test
     "pytest",
     "freezegun",
diff --git a/pyrefly.toml b/pyrefly.toml
new file mode 100644
index 0000000..f101c19
--- /dev/null
+++ b/pyrefly.toml
@@ -0,0 +1 @@
+preset = "default"
diff --git a/tests/test_formatters.py b/tests/test_formatters.py
index 3f12fcc..df32f98 100644
--- a/tests/test_formatters.py
+++ b/tests/test_formatters.py
@@ -38,9 +38,9 @@
 ### ============================================================================
 ALL_FORMATTERS: list[type[BaseJsonFormatter]] = [JsonFormatter]
 if pythonjsonlogger.ORJSON_AVAILABLE:
-    ALL_FORMATTERS.append(OrjsonFormatter)
+    ALL_FORMATTERS.append(OrjsonFormatter)  # type: ignore[unbound-name]
 if pythonjsonlogger.MSGSPEC_AVAILABLE:
-    ALL_FORMATTERS.append(MsgspecFormatter)
+    ALL_FORMATTERS.append(MsgspecFormatter)  # type: ignore[unbound-name]
 
 _LOGGER_COUNT = 0
 
diff --git a/tox.ini b/tox.ini
index aeea355..707d512 100644
--- a/tox.ini
+++ b/tox.ini
@@ -21,4 +21,4 @@ commands =
     validate-pyproject pyproject.toml
     black --check --diff src tests
     pylint src
-    mypy src tests
+    pyrefly check src tests