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Minify JavaScript by removing comments, trimming whitespace, and outputting cleaner code instantly in your browser.
JavaScript Minifier compresses JS source code by removing comments, stripping whitespace, shortening local variable names, and eliminating dead code branches — all without changing what the script does at runtime. Paste your JavaScript and the tool returns a minified version along with a before/after size comparison. Minification is the single most impactful step you can take to reduce JS payload: scripts that drive interactive behaviour must be downloaded and parsed before the browser can execute them, and every kilobyte saved translates directly to faster interaction readiness. A typical utility script compresses 30–50%; large application bundles with verbose variable names and formatted code can compress 60% or more.
The browser must parse every byte of JavaScript before it can build the call graph. Smaller scripts parse faster, unblocking the main thread sooner and improving Total Blocking Time — one of Google's Core Web Vitals metrics.
Local variables with descriptive names like userAuthenticationToken become single characters like a in the minified output. This alone can shrink variable-heavy utility code by 20–30% beyond whitespace removal.
Block comments, inline comments, and JSDoc annotations are valuable in source but invisible at runtime. Removing them eliminates documentation payload from production scripts without touching the source file.
Arrow functions, optional chaining (?.), nullish coalescing (??), async/await, destructuring, and private class fields are all handled correctly. The minifier compresses without transpiling.
Projects that ship plain JS files without Webpack, Rollup, or esbuild still need minification before production. This tool provides the final compression step with a paste-and-copy workflow.
The before/after size display lets you measure the exact impact of minification on your specific script and decide whether further optimisations — code splitting, tree-shaking — are worth the effort.
Input: /** * Formats a number as a currency string. * @param {number} amount - The amount to format. * @param {string} currency - ISO 4217 currency code. * @returns {string} Formatted currency string. */ function formatCurrency(amount, currency = 'USD') { // Use Intl.NumberFormat for locale-aware formatting const formatter = new Intl.NumberFormat('en-US', { style: 'currency', currency: currency, }); return formatter.format(amount); }
Output: function formatCurrency(a,b='USD'){return new Intl.NumberFormat('en-US',{style:'currency',currency:b}).format(a);}
Input: // Get user display name with fallback const getDisplayName = (user) => { // Try full name first, then username, then anonymous const fullName = user?.profile?.fullName; const username = user?.username; return fullName ?? username ?? 'Anonymous'; };
Output: const getDisplayName=a=>a?.profile?.fullName??a?.username??'Anonymous';
Input: document.getElementById('load-btn').addEventListener('click', async function() { // Show loading state const button = this; button.disabled = true; button.textContent = 'Loading...'; try { const response = await fetch('/api/data'); const data = await response.json(); console.log('Loaded:', data); } catch (error) { console.error('Fetch failed:', error); } finally { button.disabled = false; button.textContent = 'Load Data'; } });
Output: document.getElementById('load-btn').addEventListener('click',async function(){const a=this;a.disabled=true;a.textContent='Loading...';try{const b=await fetch('/api/data');const c=await b.json();console.log('Loaded:',c);}catch(d){console.error('Fetch failed:',d);}finally{a.disabled=false;a.textContent='Load Data';}});