Solved by Flexbox is described as 'CSS has been lacking proper layout mechanisms for far too long. Transitions, animations, filters, all of these are great and useful additions to the language, but they don't address the major problems that Web developers have been complaining about for what seems like an' and is a UI Design tool in the development category. There are three alternatives to Solved by Flexbox for Online / Web-based and Self-Hosted solutions. The best alternative is Flexbox Zombies, which is free. Other great apps like Solved by Flexbox are Flexbox Patterns and Awesome Flexbox.
Solved by Flexbox alternatives are mainly Educational Games but may also be UI Design Tools or Code Editors. Filter by these if you want a narrower list of alternatives or looking for a specific functionality of Solved by Flexbox.