Retro Virtual Machine - The ZX Spectrum and Amstrad CPC emulator which works natively in macOS, Linux, and Windows.
Siberian CMS - Siberian is an Open-Source and Free App Maker. Unlimited Push Notifications. Unlimited features. Fully Customizable. Download it and build your own app now!
JSSpeccy - ZX Spectrum emulator in JavaScript
Dropsource - Mobile development platform for building native iOS & Android apps
Speccy emulator - Sinclair ZX Spectrum emulator
GoodBarber - GoodBarber is a mobile app creation platform.