Mktbox is a collection of beautifully designed and responsive tools for marketers, founders and creators. It's open source, free to use and download, and no account required. Use it for: - QR code generation - Vibe code apps audit (Lovable, Base44, Bolt and others). Does SEO, security, speed audit - UTM link builder - Keyword ideas from Google and YouTube - Opengraph link previews + LinkedIn formatter, email signatures, page speed audits, image resizer, GIF creator, headline audit and more.