Thunkable - Powerful but easy to use, drag-and-drop mobile app builder.
Voiceflow - Build voice apps in your browser without coding
MIT App Inventor - App Inventor is a cloud-based tool, which means you can create apps for phones or tablets right in your web browser.
Alexa Skill Kit - Effortless Alexa Skill development with AWS Lambda
Bubble.io - Building tech is slow and expensive. Bubble is the most powerful no-code platform for creating digital products.
API to bot - Convert your API to Alexa skill or Google Home app in 5 mins