django-fast-multipart

django-fast-multipart is a Rust-backed multipart upload parser for Django. It uses Django's parser extension point while keeping the existing upload handlers, request limits, request.POST, and request.FILES interfaces.

The project currently supports CPython 3.12 or later and Django 6.1.

Installation

python -m pip install django-fast-multipart

Prebuilt wheels are available for Linux x86-64 and ARM64, macOS Intel and Apple Silicon, and Windows x86-64. Other platforms can build from the source distribution with a Rust toolchain.

Quick start

For application-wide use, add the middleware before CSRF or anything else that reads request.POST or request.FILES:

MIDDLEWARE = [
    "django_fast_multipart.middleware.FastMultipartMiddleware",
    "django.middleware.csrf.CsrfViewMiddleware",
    # Other middleware...
]

Your views continue to use Django's normal request API:

def upload(request):
    description = request.POST.get("description", "")
    uploaded_file = request.FILES["file"]
    # Process the uploaded file.

To select it only for one view:

from django_fast_multipart import RustMultiPartParser


def upload(request):
    request.multipart_parser_class = RustMultiPartParser
    uploaded_file = request.FILES["file"]
    # Process the uploaded file.

The parser must be selected before request data is read. Both synchronous WSGI and asynchronous ASGI request stacks are supported, and non-multipart requests remain unchanged.

Documentation

Read the complete guide at django-fast-multipart.readthedocs.io. It covers installation, middleware ordering, per-view setup, upload handlers, compatibility, performance, troubleshooting, and development.

Quick performance results

In our in-process Django request benchmarks, the Rust parser reduced request parsing time for each tested workload:

The main point is simple: forms with many fields get the biggest benefit. Large uploads also improve, but file writes and Django's upload handlers take most of the time. Memory usage was broadly comparable with Django's parser.

These results are from one GitHub Actions run on Python 3.14 and Django 6.1. They measure an in-process request, not a production server or network. Read the performance guide and benchmark methodology before using the numbers for capacity planning.

Compatibility

The project is currently beta. Its behavior is extensively tested against Django's MultiPartParser, including built-in upload handlers, upload limits, WSGI and ASGI integration, and cleanup after exceptions. Production feedback for custom upload handlers is welcome.

Development

uv sync
uv run pytest
uv run ruff check .
uv run ruff format --check .
cargo fmt --manifest-path rust/Cargo.toml --check
cargo clippy --manifest-path rust/Cargo.toml --locked --all-targets --all-features -- -D warnings
uv build

See the development documentation and release guide for more details.

License

The project is licensed under MIT. See THIRD_PARTY_NOTICES.md for the native parser's upstream attribution and licensing details.