Hi, I just published an implementation of Universal Binary JSON (UBJSON) for Pharo. https://github.com/svenvc/NeoUniversalBinaryJSON Universal Binary JSON (UBJSON) is a computer data interchange format. It is a binary form directly imitating JSON, but requiring fewer bytes of data. It aims to achieve the generality of JSON, combined with being easier and more efficient to process than JSON. http://ubjson.org https://en.wikipedia.org/wiki/UBJSON The size/speed/efficiency differences are minor for typical JSON payloads, especially compared with compacted JSON. The implementation is simpler, though, as there is no string escaping and no number parsing. UBJSON is making a larger difference when dealing with arrays containing numbers. Especially with ByteArrays, UBJSON makes a huge difference, since these are essentially stored natively. Sven