A recommendation: we use rxi's json.lua at Planimeter, but upon benchmarking JSON implementations across all major languages, it was found to be the slowest by an order of magnitude when reading very large numbers of JSON files.

So if you can, try and at least use LuaJIT, which when using json.lua seems to bring it back down into range with other performant languages, or jump down into LuaJIT and use Sj.h there, through the C FFI or just simdjson.

json.lua is great for when you're restricted in some ways to use a pure Lua implementation, though. It's the de facto solution.

Other JSON libraries benchmarked here: https://github.com/andrewmcwattersandco/programming-language...