Compacting json data removing unused spaces: https://golang.org/pkg/encoding/json/#Compact

compact.go

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
)

func main() {
	data := `{ "spacedValue": "spaced value" }`
	compactedBuffer := new(bytes.Buffer)
	err := json.Compact(compactedBuffer, []byte(data))
	if err != nil {
		fmt.Println(err)
	}
	fmt.Printf("compacted buffer: %v", compactedBuffer)
}