We’ve just uploaded mypy 1.13 to the Python Package Index ([PyPI](https://pypi.org/project/mypy/)).

Mypy is a static type checker for Python. You can install it as follows:

python3 -m pip install -U mypy

You can read the full documentation for this release on [Read the Docs](http://mypy.readthedocs.io).

Note that unlike typical releases, Mypy 1.13 does not have any changes to type checking semantics

from 1.12.1.

Mypy 1.13 contains several performance improvements. Users can expect mypy to be 5-20% faster.

In environments with long search paths (such as environments using many editable installs), mypy

can be significantly faster, e.g. 2.2x faster in the use case targeted by these improvements.

Mypy 1.13 allows use of the `orjson` library for handling the cache instead of the stdlib `json`,

for improved performance. You can ensure the presence of `orjson` using the `faster-cache` extra:

python3 -m pip install -U mypy[faster-cache]

Mypy may depend on `orjson` by default in the future.

These improvements were contributed by Shantanu.

List of changes:

* Significantly speed up file handling error paths (Shantanu, PR [17920](https://github.com/python/mypy/pull/17920))

* Use fast path in modulefinder more often (Shantanu, PR [17950](https://github.com/python/mypy/pull/17950))

* Let mypyc optimise os.path.join (Shantanu, PR [17949](https://github.com/python/mypy/pull/17949))

* Make is_sub_path faster (Shantanu, PR [17962](https://github.com/python/mypy/pull/17962))

* Speed up stubs suggestions (Shantanu, PR [17965](https://github.com/python/mypy/pull/17965))

* Use sha1 for hashing (Shantanu, PR [17953](https://github.com/python/mypy/pull/17953))

* Use orjson instead of json, when available (Shantanu, PR [17955](https://github.com/python/mypy/pull/17955))

* Add faster-cache extra, test in CI (Shantanu, PR [17978](https://github.com/python/mypy/pull/17978))

Thanks to all mypy contributors who contributed to this release:

- Shantanu Jain

- Jukka Lehtosalo