Gridbox is described as 'Powerful BOOTSTRAP & HTML Builder for developers to speed up their workflow' and is an app in the Development category. There are seven alternatives to Gridbox for a variety of platforms, including Mac, Windows, Linux, CSS and Sass. The best alternative is Adobe Dreamweaver. It's not free, so if you're looking for a free alternative, you could try Foopad. Other great apps like Gridbox are Pinegrow Web Editor (Paid), Bootstrap Studio (Paid), Pingendo (Paid) and Blocs (Paid).
Pinegrow is a Mac, Windows and Linux web editor that lets you build responsive websites faster with live multi-page editing, CSS & SASS styling, CSS Grid editor and smart components for Bootstrap, Foundation and WordPress.
Bootstrap Studio is an elegant and very easy to use web design tool for building websites using the renowned Bootstrap framework. With its intuitive, drag-and-drop interface, new users can easily get great designs in just moments.
Foopad is nondestructive source code editor / integrated development environment made to make your dev life better. Foopad has some unique features and can be customized to be like simple notepad or full IDE.