Yes... and no. Read on!
Whether it's the webapp or desktop app, we recommend fully loading Interviewerr (including the interview screen) before going offline.
To use the Interviewerr web-app offline you will need to be online to load the app, login and open a new interview. At this point the App is fully loaded, and should be stable offline.
Once recording your internet can flicker or fail entirely and both audio and notes (old and new) will be preserved. You will see indications of the app continually trying to upload data, these will continue until the app has reconnected and is able to upload each snippet of data.
Even if you close the web-app while disconnected, the data will remain preserved for 24 hours or until upload is complete; meaning you can complete an interview offline, travel to a new destination and still safely upload your audio and notes.
For a better and safer offline experience, particularly in offline use, we recommend using the Desktop app where preservation of data will be more secure than in-browser.