The best open source alternative to Bootstrap Studio is Layoutit, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 50 alternatives to Bootstrap Studio and three of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Bootstrap Studio are Gramateria (Free, Open Source) and Grapedrop (Freemium, Open Source).
Layoutit is a drag&drop page layout builder that outputs Bootstrap 3 code. It supports: * Bootstrap grid elements * CSS enhancements of fundamental HTML elements (list, table, form etc.) * components (button group, thumbnail, panel etc.
Most users think Layoutit is a great alternative to Bootstrap Studio.
Gramateria is a drag & drop web builder with bootstrap, grapes js and electron js. Gramateria 1.0.6 is a re-written version that changed many features, it allows you to manage and deploy your web pages to Netlify.