https://medium.com/@kanishkablack/analysis-of-json-parser-for-elixir-d1aed8332ce7

Well, Elixir is been moved into production in serious environments. One of the major deployment, I came across is JSON API or JSON related endpoints on Elixir application.

We have observed that, Poison used to be and still being used as JSON parser in many major modules. Now, Jason is default in phoenix application, for its performance upgrades.

This is good for small scale application, but when the application has to process 5MB/sec and when application have to process about 4–5TB/data a day. Even Jason falls short.