ForHosting KIT · Developer Utilities

JavaScript Beautifier

The JavaScript beautifier turns compressed or inconsistently spaced source into code that is easier to inspect, explain, and review.

● BetaFree · in your browser

Run — free How it works & API

Use it from WebAPIEmailTelegramApp soon

Paste a minified script, bundled fragment, inline handler, or generated snippet and receive a deterministic layout with two-space indentation and line breaks after statements. The scanner protects quoted strings, template literals, comments, and regular expression literals while it formats structural punctuation. It also rejects mismatched or unfinished brackets, parentheses, and braces, helping you detect a truncated copy before you rely on the formatted result.

Make compressed JavaScript readable again

JavaScript delivered to browsers is commonly minified so that files transfer quickly, but the same compact representation is difficult for a person to follow. Function bodies, variable declarations, calls, conditions, and return statements can all occupy one uninterrupted line. This beautifier restores a stable visual hierarchy without executing the submitted program. Opening braces begin indented blocks, closing braces return to the preceding level, and statement-ending semicolons create line breaks when they occur outside parenthesized expressions. Two spaces are used for every indentation level, so repeated runs produce a predictable result suitable for a note, ticket, code review, or editor. The formatter is particularly helpful when the only available source is an asset copied from a browser, a build directory, an embedded page script, or a diagnostic response. It does not rename variables, expand bundled modules, infer original source maps, or promise to reconstruct an author's preferred style. Its purpose is narrower and dependable: expose the submitted program's visible structure while retaining its meaningful characters.

Protect strings, comments, templates, and regular expressions

Punctuation has different meanings in different parts of JavaScript, so a useful formatter cannot split text at every brace or semicolon it sees. A semicolon inside a quoted message is data. Brackets inside a regular expression describe a character class. A brace inside a template literal may be ordinary output, and punctuation in a comment must not alter the program structure. The scanner therefore tracks single-quoted and double-quoted strings, escape sequences, template literals, line comments, block comments, and regular expression literals. Structural formatting occurs only outside those protected regions. Parentheses are tracked as well, preventing semicolons in a traditional for-loop header from becoming separate lines. This deterministic character scan uses no network connection, clock, random choice, model, or runtime evaluation. Identical input produces identical output, and the submitted JavaScript never runs as part of beautification. The result is designed for human inspection and subsequent tooling while preserving sensitive literal contents exactly as supplied. Because JavaScript grammar contains contextual ambiguities, this is a structural beautifier rather than a replacement for a full standards parser or project-specific formatter.

Catch incomplete delimiters before further work

Formatting is often requested precisely when source has been copied from an inconvenient place, and copying can omit a character at either end. The beautifier maintains a nested stack of structural opening delimiters and checks every closing delimiter against it. An unexpected closing parenthesis, square bracket, or brace produces an invalid-input error at once. Reaching the end with an opening delimiter still on the stack also fails instead of returning output that merely looks polished. Delimiters inside protected strings, comments, template literals, and regular expression literals are treated as content rather than program structure. This check is intentionally focused. Balanced delimiters do not prove that identifiers, operators, declarations, module syntax, or control flow are valid JavaScript, and the tool does not execute code to test its behavior. They do provide a valuable warning for common truncation and mismatch errors before a snippet enters documentation, review, comparison, or a more specialized parser. Browser formatting can run locally, while automated API requests use the published base price of $0.002 per item.

What you can do with it

Inspect a minified browser asset

Expand a compressed script into indented blocks and statement lines before tracing a function, event handler, or suspicious call.

Prepare a snippet for review

Apply deterministic layout to generated or inconsistently formatted JavaScript so reviewers can focus on behavior and structure.

Check a copied script fragment

Detect missing or mismatched parentheses, square brackets, and braces before placing copied code in documentation or another tool.

FAQ

What formatting does the beautifier apply?

It uses two-space block indentation and places semicolon-terminated statements on new lines outside parenthesized expressions.

Does the tool execute my JavaScript?

No. It performs a deterministic text scan and never evaluates or runs the submitted source.

Are strings, comments, templates, and regular expressions preserved?

Yes. Their contents are protected from structural line breaking while the scanner processes the surrounding code.

Does balanced punctuation guarantee valid JavaScript?

No. The tool checks delimiter balance and formatting boundaries, but it is not a complete ECMAScript syntax validator.

How much does an API request cost?

Each API request uses the published base price of $0.002. The browser version can run locally without an API request.

For developers — API access

Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.

API endpoint

POSThttps://api.kit.forhosting.com/dev2/beautify-js

Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.

Call it from your stack

curl -X POST https://api.kit.forhosting.com/dev2/beautify-js \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"javascript":"function greet(name){const message=`Hello, ${name}!`;console.log(message);return message;}"}'

const res = await fetch("https://api.kit.forhosting.com/dev2/beautify-js", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "javascript": "function greet(name){const message=`Hello, ${name}!`;console.log(message);return message;}"
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/dev2/beautify-js",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "javascript": "function greet(name){const message=`Hello, ${name}!`;console.log(message);return message;}"
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/dev2/beautify-js", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"javascript":"function greet(name){const message=`Hello, ${name}!`;console.log(message);return message;}"}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"javascript":"function greet(name){const message=`Hello, ${name}!`;console.log(message);return message;}"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/dev2/beautify-js", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "javascript": "function greet(name){const message=`Hello, ${name}!`;console.log(message);return message;}"
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "dev2.beautify_js",
  "status": "queued",
  "_links": {
    "result": "/tasks/tsk_…/result"
  }
}

The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.

Pricing

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

Errors

HTTP	Code	Meaning
`401`	`unauthorized`	Missing or invalid API key.
`402`	`insufficient_balance`	Your balance doesn't cover the task price.
`404`	`unknown_type`	That task type doesn't exist.
`429`	`rate_limited`	Too many requests. Use the webhook instead of polling.

Read the full KIT documentation →