from Hacker News

Show HN: Turn any WiFi into a persistent group chat

by melvinmt on 4/30/19, 2:43 PM with 56 comments

Try it out on your WiFi: https://tapchat.com

I’ve always been shocked at the fact that it’s easier to chat with someone on the other side of the world than with someone who is on the exact same WiFi as you. I think that is a shame because WiFi networks are essentially a bunch of existing micro-communities which your phone already automatically connects to. Think about how many other people have used or will use the same WiFi as you at home, school, work, or in public; and so far it has been practically impossible to chat or share pictures with them.

After leaving my job earlier this year, I decided to work on a simple chat app that solves this problem, by simply opening a persistent group chat for every WiFi you connect to, which allows for long-lasting conversations and meaningful relationships everywhere you go. So far a great use case I've seen are college campuses where thousands of students connect to the same WiFi, and who can now all chat with each other. I'd love to see what else this can or will be used for.

(Spoiler alert: the app doesn’t bother with mesh networks)

Feedback is much appreciated! (the gentle kind)

  • by youeseh on 4/30/19, 10:35 PM

    I have an organic growth marketing suggestion: - Laptop stickers. Start with your own laptop. See if people come online and talk to you. If they do, ask them if they'd like a sticker too. Tell them that they can gift a sticker to a friend from the website.

    - Also, a desktop app / plugin for Slack / Discord / something else. I don't pay attention to my phone when I'm working but I am on a few chats that I check on and off on my laptop.

  • by zamadatix on 4/30/19, 9:39 PM

    So how does it work? When you say "same SSID" do you mean your app uses broadcast/multicast across the network or do you mean you are saving the SSID/BSSID and centralizing the conversations in a cloud database? In the first case how do you deal with the majority of large Wi-Fi networks that disable peer to peer communication? In the latter case how do you differentiate if it's SSID not BSSID?

    I suppose I could find out if I downloaded the app and tried it out but I'd rather read about how the app works than just run random programs on my phone. The website itself doesn't give much to go off of in terms of feedback-able content and the app pages just show some messages.

  • by OkGoDoIt on 4/30/19, 11:08 PM

    It feels like this should work over a local network without requiring an internet connection. Or are you focused on just using SSID as a form of authentication for chat rooms on the internet? If so, what's to stop me from setting my router's SSID to something like "AppleCampusInternalWifi" and getting access to something that might be assumed to be private?

  • by tjpnz on 4/30/19, 11:37 PM

    I was travelling recently with a group of people and wondered whether something like this might exist. My use case was to have a way of easily sharing photos with people close by (we were all being driven around in the same car) without the need to involve anything dodgy like Facebook. WiFi did cross my mind as we were all connected via the same pocket WiFi adapter although I was wondering if it could be made to work without an internet connection. Especially useful when you're travelling through regions with patchy cell coverage.

  • by fiatjaf on 5/2/19, 1:01 AM

    I've collected a bunch of interesting services for LANs at https://github.com/fiatjaf/awesome-lan. I'll add Tapchat too although it's missing a desktop app.

  • by oneowl on 5/1/19, 7:13 AM

    This is a great idea, well done! I think as a next step you should look a bit more into routers themselves. You can flash them with an opensource os like openwrt [1] and run a chat (or some kind of communication) server on it so everybody connected to the same wifi can freely exchange data.

    This way you can turn any wireless capable [2] machine into a small community network.

    > great use case I've seen are college campuses where thousands of students connect to the same WiFi,

    This is indeed a great use case. Right now you're only thinking about chat but its got more applications like semi-remote teaching,tests ,role calls etc. But (I think) its far easier to realize it if you work at the network level rather than at the app level.

    Best of luck!!!!

    [1] https://openwrt.org

    [2] router, raspberry pi, laptop, your phone

  • by toyg on 5/1/19, 8:17 AM

    Congratulations, this is an idea I’ve long sat on. I used to travel a lot on trains and planes, and always wished there was a way to break the ice with fellow travelers without looking like a psycho or annoying chatterbox (particularly early in the morning). There are additional challenges for those situations (bad connectivity), so I am not recommending to pursue that story, I’m just saying I think you had the right idea. Good luck!

  • by CGamesPlay on 5/1/19, 7:27 AM

    This is a neat idea! I’m traveling a lot presently so from my perspective two things that might be useful are:

    - Make it really easy to exchange persistent contact info. Something like a 1-tap share of your phone number either to the group or to a specific person in the group.

    - Scrape public WiFi databases like Wifi Map Pro for places travelers are likely to be (hotels and hostels) and prime the chat with local recommendations.

  • by sanqui on 5/1/19, 8:49 AM

    Does it work offline (i.e. without an internet connection)? The website and explanation here is sort of unclear.

  • by tarun_anand on 5/1/19, 2:19 AM

    Could it be used as an sdk to pass small amounts of data around - think multi-player games....

  • by powerset on 5/1/19, 12:49 AM

    I'm curious why you chose to make it a mobile app instead of browser based.

    Would it be possible to build it such that, when I visit the site I'm automatically dropped directly into the local chat room for whatever wifi network I'm currently on?

  • by sandwich9 on 5/2/19, 4:31 PM

    This is neat! What were a couple of your biggest challenges when creating this?

    Does the number connections to a router effect how many people can join? I think around 250 is the limit thought some have problems after 50.

  • by chachachoney on 5/1/19, 4:05 PM

    Do you provide any privacy/security guarantees regarding the stored chats or user location data and access logs?

    Do you intend to monetize this by making any of the information mentioned above available to third parties?

  • by garysahota93 on 4/30/19, 9:26 PM

    This, in theory, is really cool! Have you thought about making this into a work chat like app? I could totally see this being used at work with all my colleagues in the office.

  • by butz on 5/1/19, 8:53 AM

    Clicking on "Google Play" button just flashes modal for a fraction of second. Firefox 66.

  • by flyingfences on 4/30/19, 9:36 PM

    Hmmm, for my campus network it just says <unknown SSID> which isn't quite right.

  • by tdaniels on 5/1/19, 7:38 AM

    This is an awesome idea. The app is crashing on startup for me however at the moment

    *edit Android version 9

  • by anbop on 5/1/19, 8:50 AM

    Random people sending me messages just because we’re on the same WiFi is my personal hell

  • by ronsor on 4/30/19, 10:33 PM

    Why do you use an external server? Why not use UDP multicast or something?

  • by TejasGupta on 4/30/19, 8:43 PM

    What about for desktop?

  • by fiatjaf on 5/2/19, 12:59 AM

    I wanted something like that, but in the browser.

  • by bayareanative on 5/1/19, 8:18 AM

    FireChat works over BT without any WiFi.

  • by purpleidea on 5/1/19, 8:20 AM

    You can already chat with avahi.

  • by nittanymountain on 4/30/19, 10:21 PM

    this is cool!

  • by bifrost on 4/30/19, 10:13 PM

    That is topkeks to see you advertising your HN post on FB. I really gotta ask why though...