Dear numpy developers, I would like to share a proposal on making ndarray JSON serializable by default, as detailed in this github issue: https://github.com/numpy/numpy/issues/20461 briefly, my group and collaborators are working on a new NIH (National Institute of Health) funded initiative - NeuroJSON (http://neurojson.org) - to further disseminate a lightweight data annotation specification (JData <https://github.com/NeuroJSON/jdata/blob/master/JData_specification.md>) among the broad neuroimaging/scientific community. Python and numpy have been widely used <http://neuro.debian.net/_files/nipy-handout.pdf> in neuroimaging data analysis pipelines (nipy, nibabel, mne-python, PySurfer ... ), because N-D array is THE most important data structure used in scientific data. However, numpy currently does not support JSON serialization by default. This is one of the frequently requested features on github (#16432, #12481). We have developed a lightweight python modules (jdata <https://pypi.org/project/jdata/>, bjdata <https://pypi.org/project/bjdata/>) to help export/import ndarray objects to/from JSON (and a binary JSON format - BJData <https://github.com/NeuroJSON/bjdata/blob/master/Binary_JData_Specification.md>/UBJSON <http://ubjson.org/> - to gain efficiency). The approach is to convert ndarray objects to a dictionary with subfields using standardized JData annotation tags. The JData spec can serialize complex data structures such as N-D arrays (solid, sparse, complex). trees, graphs, tables etc. It also permits data compression. These annotations have been implemented in my MATLAB toolbox - JSONLab <https://github.com/fangq/jsonlab> - since 2011 to help import/export MATLAB data types, and have been broadly used among MATLAB/GNU Octave users. Examples of these portable JSON annotation tags representing N-D arrays can be found at http://openjdata.org/wiki/index.cgi?JData/Examples/Basic#2_D_arrays_in_the_a... http://openjdata.org/wiki/index.cgi?JData/Examples/Advanced and the detailed formats on N-D array annotations can be found in the spec: https://github.com/NeuroJSON/jdata/blob/master/JData_specification.md#annota... our current python module to encode/decode ndarray to JSON serializable forms are implemented in these compact functions (handling lossless type/data conversion and data compression) https://github.com/NeuroJSON/pyjdata/blob/63301d41c7b97fc678fa0ab0829f76c762... https://github.com/NeuroJSON/pyjdata/blob/63301d41c7b97fc678fa0ab0829f76c762... We strongly believe that enabling JSON serialization by default will benefit the numpy user community, making it a lot easier to share complex data between platforms (MATLAB/Python/C/FORTRAN/JavaScript...) via a standardized/NIH-backed data annotation scheme. We are happy to hear your thoughts, suggestions on how to contribute, and also glad to set up dedicated discussions. Cheers Qianqian