Msgpack
It's like JSON but fast and small.
Python
https://github.com/msgpack/msgpack-python
Javascript
https://www.npmjs.org/package/msgpack-js
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npm install msgpack-js
node packtest.js
packtest.js
var msgpack = require('msgpack');
var assert = require('assert');
var initial = {Hello: "World"};
var encoded = msgpack.encode(initial);
var decoded = msgpack.decode(encoded);
assert.deepEqual(initial, decoded);