Karelia Software says that Sandvox (http://www.karelia.com/sandvox), its web development tool, is now available in the Mac App Store. Through Oct. 31, it’s available at a special introductory price of US$$49.99 (it’s regularly $79.99) and requires Mac OS X 10.5 or higher.

The new Sandvox 2.1.10 adds a new Blueprint design, and builds on the new SFTP publishing system recently introduced with new WebDAV and MobileMe publishing subsystems. Sandvox lets you drag and drop content, add modern features in a few clicks, and see exactly what it looks like right on the screen before hitting publish.

Sites created using Sandvox automatically comply with the latest HTML5 web standard, and can be seen on modern mobile devices, according to the folks at Karelia Software. Once finished, users can upload their site to their favorite host directly from within Sandvox.