JavaScript Validator

Module mode parses your code as an ES module, so import and export statements and top-level await are allowed and strict mode is implied. Script mode parses a classic script, where a top-level return is allowed (as in a CommonJS wrapper) but import and export are not. Pick the mode that matches how the code will run.

No — it only parses your code to check that the syntax is valid; it never executes it, and it is not a style linter. Parsing runs entirely in your browser with Acorn, nothing is uploaded. As an EU-built, EU-hosted provider, Uptimeify keeps your workflow off US infrastructure and clear of US Cloud Act exposure.

A single syntax error can take a whole page down. Validate scripts before you ship, then let Uptimeify watch the live site from multiple EU locations — if a broken deploy slips through, you get an alert within seconds instead of hearing it from a client.