easyjson VS jsoniter

Compile time means you catch issues at... well compile time. It also means that the code is optimized. You can look at the performance different between encoding/json and easyjson for why you may desire that.

easyjson produced an empty file

There is https://github.com/mailru/easyjson out there if you are absolutely sure that serialization is the bottleneck. Otherwise I'd go for stdlib.

https://github.com/mailru/easyjson fast JSON (de)serializer which go generates code instead of using reflect at runtime.

If you know the schema of the JSON ahead of time and you need to parse the whole object, I would recommend https://github.com/mailru/easyjson as that will likely give you the fastest result. This works in almost all use cases, and easy to use features such as string interning can save you a lot of time on memory allocation if you parse a lot of JSON objects with identical values.

What to use Easyjson is about the top of the pack and it's straightforward. The downside of efficient tools is that they use code generation to create the code required to turn your structs into json to minimise allocations. This is a manual build step which is annoying. Interestingly json-iterator also uses reflection but it's significantly faster. I suspect black magic.

I'm looking for something similar to https://github.com/mailru/easyjson where one can generate a concrete JSON parser for some types.

Бібліотека easyjson теж для серіалізації працює через додатковий код замість використання рефлексії. Але після внесення в easyjson одної з оптимізацій, час від часу почали отримувати зламаний JSON, ось приклад тесту який покаже помилку.

Since most of the time would be spent decoding json, you could try to cut this time using https://github.com/bytedance/sonic or https://github.com/json-iterator/go, both are drop-in replacements for the stdlib, sonic is faster.

We all know the builtin golang JSON parser is slow.

How about doing comparisons against other implementations?

Like this one: https://github.com/json-iterator/go

Json-iterator (https://github.com/json-iterator/go), you can replace all of encoding/json with this. It does the same thing but it's faster.

Do you want to look at every field all at the same time? If not, you can pick out individual fields. There's other packages such as https://github.com/tidwall/gjson or https://github.com/json-iterator/go that let you pass in paths such as "a.b.c" to extract single fields.

For each Go type used within the config, we generate a separate unmarshaller function. The unmarshallers use json-iterator to process the output from CUE, while tracking the path within the config to the unmarshalled value. This path tracking will allow the function to check if live overrides have been provided on that path and return the override instead.

https://github.com/json-iterator/go an alternative JSON encoding package which allows to stream (flush out) encoded data as soon as it's able to (which is in contrast with the stock package which buffers everything until the encoding is known to be complete and OK).

What to use Easyjson is about the top of the pack and it's straightforward. The downside of efficient tools is that they use code generation to create the code required to turn your structs into json to minimise allocations. This is a manual build step which is annoying. Interestingly json-iterator also uses reflection but it's significantly faster. I suspect black magic.

jsoniter for low level access to JSON encode and decode

Takes like 10 minutes to write and parses very efficiently. https://github.com/json-iterator/go looks like it can provide such simple parsing