A demo can be found at https://vocalize.herokuapp.com The demo is updated inbetween complete feature releases.
Vocalize depends on audio and recording APIs that are not supported by older browsers and requires that the browser in use has microphone permissions from the device.
iPhone / Android devices running Chrome can run Vocalize well but Chrome must be given access to the microphone via the device settings as this is disabled by default. The user will then be asked for mic permissions from Vocalize on the Recorder page.