LLHTTP ------ When building aiohttp from source, there is a pure Python parser used by default. For better performance, you may want to build the higher performance C parser. To build this ``llhttp`` parser, first get/update the submodules (to update to a newer release, add ``--remote``):: git submodule update --init --recursive Then build ``llhttp``:: cd vendor/llhttp/ npm ci make Then build our parser:: cd - make cythonize Then you can build or install it with ``python -m build`` or ``pip install -e .``