I'm looking for a group chat tool with minimal onboarding for folks in the same physical space. Ideally, users wouldn't have to create an account at all: they could just scan a QR code, enter their name, and start participating. Something fully web-based with support for desktop and mobile browsers would be ideal.
The use case is for a small conference, where participants will physically arrive at a lounge and check in. At that point we'll give them some materials, including information about how to join the chat. A short while later, people will spread out into several smaller spaces. We intend to post QR codes in each of those spaces for joining the chat as well.
The chat will be used mostly for side-channel communication, though we may post "official" stuff in there as well, e.g. "Item X on the agenda will be starting in five minutes".
We've considered Signal and WhatsApp (both have more onboarding than I'd like) as well as Slack and Discord. We probably don't need multiple channels, but private messaging would be good to have. Discord feels like the closest choice, but it also seems like overkill, and I'd like to avoid making folks install an app on their phones.
Is there anything out there that fits the bill?