Principle vs Proto.io
| Principle | Proto.io | |
|---|---|---|
| Free plan | No | No |
| Free trial | No | Yes |
| Paid from | $99/mo | $29/mo |
| Open source | No | No |
| Platforms | Web, macOS, iOS | Android, iOS, Web |
| Free plan | No | Yes |
| Design systems | Yes | Yes |
Both are listed in Best Web Design Software, Best UI Design Tools, Best Game UI Design Software, Best Prototyping Software. On Inferse, Proto.io scores higher on our published basis.