When building JSON APIs you often find yourself in a situation when you have part of the JSON already encoded and want to embed it in a bigger structure. A common solution is to decode the encoded part and embed the outer structure just to encode it back again. It’s obvious how that back-and-forth decoding and encoding is wasteful. Fortunately with poison we have a much better alternative.

http://michal.muskala.eu/2017/01/25/serving-encoded-json-with-poison.html