Pretty print JSON

I have a bunch of JSON objects that I’d like to print to the screen.
I’d like to sort the keys to make them easier to read.
This python code does what I want:

#!/usr/bin/env python3
import json

def reorder(s):
    o = json.loads(s)
    return json.dumps(o, sort_keys=True)

input1 = '{"b": 2, "A":1, "c": {"d": 3}}'
input2 = '{"c": {"d": 3}, "b": 2, "A":1}'


{"b": 2, "A":1, "c": {"d": 3}}
{"c": {"d": 3}, "b": 2, "A":1}

{"A": 1, "b": 2, "c": {"d": 3}}
{"A": 1, "b": 2, "c": {"d": 3}}

I tried using json.Unmarshal and json.Marshal but it filters out lowercase keys.
It also leaves no spaces in the output, which is a little hard to read.

I don’t know the format of the messages ahead of time.
I only know that they will be JSON objects.

Anyone have a good way of doing this?

Can you use jq ?

jq is a good idea. I could use that, but would prefer a pure Go solution, without dependencies if possible.

Lots of good info there, but most of the answers print the json on multiple lines. I need it all to be on a single line.

I had a mistake in the original question.
json.Unmarshal and json.Marshal do not filter out lowercase keys.
It puts lowercase stuff at the end so I didn’t see it in the output.

So this code does the alphabetical ordering right.

package main

import (

func reorder(obj string) string {
	var o map[string]interface{}
	json.Unmarshal([]byte(obj), &o)
	r, _ := json.Marshal(o)
	return string(r)

func main() {
	input1 := `{"b": 2, "A":1, "c": {"d": 3}}`
	input2 := `{"c": {"d": 3}, "b": 2, "A":1}`


{"b": 2, "A":1, "c": {"d": 3}}
{"c": {"d": 3}, "b": 2, "A":1}


It would just be much more readable if there was a space after each colon and comma.

To pretty print your JSON instead of Marshal function you can simply use MarshalIndent. About reordering, yeah, you can imagine a function to do this but keep in mind that JSON is a format for data exchange and the order of elements is not guaranteed and should not mater.

The JSON Data Interchange Standard definition at specifies that “An object is an unordered [emphasis mine] set of name/value pairs”, whereas an array is an “ordered collection of values”. In other words, by definition the order of the key/value pairs within JSON objects simply does not, and should not, matter .

Ordering Elements within JSON Objects – FileMakerHacks.

1 Like

Thanks for everyone’s suggestions!

The only way I found to do what I want is to parse the output of the
Token function of the JSON encoder in the standard lib.


seems to do what I want. Which is:

  • Print objects sorted alphabetically by key.
  • Print on a single line.
  • Print a space after each comma and semicolon.
  • The outermost JSON is always an object. Inside it can contain any valid JSON.

It seems like a silly amount of code just to add some spaces to the JSON,
but at least it was fun code to write.

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