This is a simple web-based voicebot built against api.ai backend. It implements a static client app, as well as a simple web service for doing math.

This is running at voicebot.jaanus.com.

This is a static web application. Run it with any local or cloud-based web server that can serve static files.

Due to browser voice API microphone security/permission requirements, it’s best to run it over HTTPS, not plain HTTP. From Google docs:

Pages hosted on HTTPS do not need to ask repeatedly for permission, whereas HTTP hosted pages do.

Blog post: How to build a simple web-based voice bot with api.ai