JavaScript Formatter

How to use

1. 1Paste minified, dense, or messy JavaScript into the input area on the left. Use the sample buttons to try a minified bundle, an IIFE, an ES class, an async/await snippet, an object literal, regex-heavy code, or template literals.
2. 2Pick the indent (2 spaces, 4 spaces, or tab) that matches your project's style guide. Output updates as you type.
3. 3Optionally rewrite quotes (preserve, single, or double) and insert missing semicolons. Pick LF for Unix and git or CRLF for Windows.
4. 4Click Copy output to copy the pretty printed code, or use Replace with output to keep formatting and iterate further with different options.
5. 5Read the parser notes panel if the input had an unterminated string, an unclosed comment, or an unfinished template literal so you know what was treated as best-effort output.

About this tool

JavaScript Formatter takes minified bundles, dense one-liner snippets from Stack Overflow, network-tab dumps, inline <script> contents, IIFEs, polyfills, webpack chunks, and modern ES code with classes, arrows, async/await, spread, destructuring, and template literals, then pretty prints them with consistent indentation, spacing, and line breaks so the structure becomes readable. The tokenizer is string-aware, regex-aware, and template-literal aware: it knows when a forward slash starts a regex literal versus when it is the division operator, which is the central source of bugs in naive JavaScript beautifiers; it handles ${...} placeholders inside template literals including nested templates and quoted strings; and it preserves both // line comments and /* ... */ block comments at their original position. The printer indents the source one level per open brace, bracket, or paren depth using either two spaces, four spaces, or a tab character; it places each statement on its own line, each property of a multi-property object literal on its own line, and each item of a multi-item array literal on its own line; it folds empty {} and [] back onto a single line; it keeps for-loop headers like for (let i = 0; i < n; i++) on a single line by recognizing that semicolons inside that paren do not terminate a statement; it keeps } else, } catch, } finally, and } while on the same line as the closing brace so do/while and if/else chains read naturally; and it preserves a single blank line between top-level declarations when the source had one. The optional quote selector rewrites double-quoted string literals to single quotes (or single to double) with proper handling of embedded escapes, the optional semicolon selector inserts a trailing semicolon at the end of statement lines that are missing one, and the line-ending selector emits LF (\n) for Unix, macOS, Linux, and git diffs or CRLF (\r\n) for Windows. Useful for developers reading a minified bundle from the Network tab, frontend engineers triaging a vendor snippet, support teams trying to make sense of an inline <script> pasted into a bug report, anyone learning JavaScript who copied an obfuscated example from a blog post, and reviewers who want to diff a compressed file against a readable expansion. The companion tool, JS Minifier, does the inverse and squashes formatted JavaScript back to a compact bundle. Everything runs locally; the JavaScript you paste here, including string contents, regex patterns, and embedded credentials in URLs or headers, never leaves your device.

Free to use. Works in your browser. No signup, no login.