Alrighty, folks. The summary is: orjson is bad due to requirement of PyO3 to run rust nightly on non-x86_64. Then what about the other contestant, rapidjson? [1] It's a wrapper over a popular C++ json library. Both wrapper and lib look alive enough to be considered serious. [1] https://pypi.org/project/python-rapidjson/ -yoctozepto