JSON Minify Online

// JSON.stringify without third argument = no whitespace (minified)
const minified = JSON.stringify(JSON.parse(jsonString));

// From a file (Node.js)
const fs = require('fs');
const data = fs.readFileSync('data.json', 'utf8');
const minified = JSON.stringify(JSON.parse(data));
fs.writeFileSync('data.min.json', minified);

// Express: disable pretty-printing in production
app.set('json spaces', 0); // default — already minified
res.json(data);

import json

json_string = '{ "name": "Alice", "age": 30 }'
# separators=(",", ":") removes the default space after , and :
minified = json.dumps(json.loads(json_string), separators=(',', ':'))
# Output: {"name":"Alice","age":30}

# From a file
with open('data.json') as f:
    data = json.load(f)
with open('data.min.json', 'w') as f:
    json.dump(data, f, separators=(',', ':'))

package main

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

func main() {
    src := []byte(`{ "name": "Alice", "age": 30 }`)

    // json.Compact removes all insignificant whitespace
    var buf bytes.Buffer
    if err := json.Compact(&buf, src); err != nil {
        panic(err)
    }
    fmt.Println(buf.String())
    // Output: {"name":"Alice","age":30}
}

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.JsonNode;

ObjectMapper mapper = new ObjectMapper();
// writeValueAsString defaults to compact — no INDENT_OUTPUT
JsonNode node = mapper.readTree(jsonString);
String minified = mapper.writeValueAsString(node);

<?php
$jsonString = '{ "name": "Alice", "age": 30 }';

// json_encode without JSON_PRETTY_PRINT = compact output
$minified = json_encode(json_decode($jsonString));
// Output: {"name":"Alice","age":30}

// From a file
$data = json_decode(file_get_contents('data.json'));
file_put_contents('data.min.json', json_encode($data));

using System.Text.Json;

string jsonString = """{ "name": "Alice", "age": 30 }""";

// Default options: WriteIndented = false → compact output
using var doc = JsonDocument.Parse(jsonString);
string minified = JsonSerializer.Serialize(doc.RootElement);
// Output: {"name":"Alice","age":30}

// Newtonsoft.Json
using Newtonsoft.Json;
var obj = JsonConvert.DeserializeObject(jsonString);
string minifiedNJ = JsonConvert.SerializeObject(obj, Formatting.None);