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.

Performance

Reference microbenchmarks show the clearest reduction in parser overhead for field-heavy forms and in-memory uploads. Temporary-file uploads benefit less because file I/O and upload-handler work dominate. These results are parser-level measurements, not end-to-end application guarantees; see the benchmark methodology for details.

Project status

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.