It's Poison, a hex package for Elixir. It blows up if you try to parse a number somewhere between "1e308" and "1e309". That is a limitation of the Elixir standard lib. Elixir doesn't try to handle that in a special way, it just raises and exception. I'd love to see something like a BigFloat, or an plug-in hook giving you the option to not explode if you didn't want to.

In Ruby, when you parse "1e309" with the built in JSON gem, you get "Infinity". That drives me bonkers, too :)