Dialogflow - Conversational UX Platform. (ex API.ai)
Zonka Feedback - Top feedback app designed to collect customer feedback on iPad & Android tablets, Online Surveys on Website, Mobile, Email & SMS. Track NPS & Other Metrics.
Botpress - Open-source platform for developers to build high-quality digital assistants
FeedbackServer - asp.net survey software Web based and open source software, for purchase or hosted, written in ASP.NET for Nsurvey
Messenger Platform - Discovery, chat extensions, and richer experiences
KeySurvey - KeySurvey provides survey and questionnaire tools.