Alexa Skill Kit - Effortless Alexa Skill development with AWS Lambda
Jovo - ๐ฃ Build cross-platform apps for Alexa and Google Home
BotTalk - Create Alexa skills and Google Assistant actions with Markup
API to bot - Convert your API to Alexa skill or Google Home app in 5 mins
Actions on Google - The open platform for Google Assistant
Voiceflow - Build voice apps in your browser without coding