Compare JavaScript

A JavaScript diff tool compares two JS files and highlights every line-level difference — added lines in green, removed lines in red. It is useful for reviewing minified vs source output, comparing build artefacts, and auditing third-party script changes.

Yes, but the result is nearly unreadable. Beautify both files first using the JavaScript Formatter tool, then compare. The formatted diff shows meaningful structural changes — function additions, logic changes, new imports — rather than a wall of single-line differences.

Paste the old bundle into the left panel and the new bundle into the right. For large bundles, first format both with a JS beautifier. Look for new function definitions, changed variable names, and added dependencies. Source maps (if available) point you to the original source file for each changed section.

A character diff highlights every individual character that changed — useful for spotting renamed variables or typos. A word diff highlights complete tokens (identifiers, operators, string literals) — easier to read for logic changes. Word diff is the default since it matches how developers think about code changes.

No. All comparison runs client-side in your browser. Your JavaScript code is never uploaded anywhere. This is safe for proprietary frontend code, internal business logic, and any JavaScript containing API keys or configuration values embedded in the source.