My (Social) Data Space

Communities: join one, or start your own

Last updated: 3 October 2026

My (Social) Data Space keeps everything on your phone and works on its own. Sharing with people nearby works out of the box, over an encrypted connection between the two phones. Sharing with a community — people who are not in the same room — goes through a community service: a small online database and file store that the community runs, pays for and answers for itself.

Nothing is built in. The app comes with no community and no server of ours. The service that receives what you publish is your choice, so you make it after installing — usually by accepting an invitation. Until then the app says so on the Feed, and what you share stays on your phone or goes to phones nearby.

In the closed test? The test service’s invitation and values are on the closed-test page. This page is the general explanation.

Join with an invitation

The easiest way in. Whoever runs the community — or any member — sends you a link or shows you a QR code.

  1. Open the link on your Android phone, or scan the QR code with the camera. With the app installed, the link opens the app directly.
  2. The app shows the service first: Community invitation ready for review. Check the address it names.
  3. Tap Use this service. Nothing is connected before you do.
  4. Choose your topics, then tap Join selected topics and get posts.

An invitation carries only the service’s address and its public connection key. It holds no password, no account and none of anybody’s entries. If a link opens in the browser instead of the app, the page shows the same three values to enter by hand, as described next.

Enter a service by hand

Three values, all of which the person running the service can give you:

Field What it looks like Where it comes from
Service URL https://xxxxxxxx.supabase.co the project’s API settings
Publishable key sb_publishable_… the same page — never a key starting with sb_secret_
Media bucket post_media preset; leave it empty unless the operator says otherwise
  1. Open My data → Settings → Community service.
  2. Paste the URL and the publishable key. Leave the media bucket as it is.
  3. Tap Use this service. The app checks that the service answers.
  4. Optional: under Save for later, give the service a name and tap Save to your services. A saved service has a Check button, which asks the service what it will actually carry — which media types, how large a file, whether its schema is current — and keeps the answer with its date.

Connecting uploads nothing you already recorded. From then on, entries you mark Public in one of its topics go there.

The app refuses a secret or service-role key by its shape. That is deliberate: a secret key inside an app on somebody’s phone is a secret no longer.

Invite your members

While you use a service, My data → Settings → Community service → Invite with link or QR shows a QR code and a Copy invitation link button. Send the link or let people scan the code. Everyone still reviews the service and taps Use this service themselves.

Start a community — Supabase as the worked example

The service is ordinary Postgres behind PostgREST plus an object store. Any Supabase project has exactly that, on the free tier, in about ten minutes.

  1. Create a project at supabase.com. Any region; the free tier is enough to start.
  2. Apply the schema. Download apply_all_2026-10-03.sql, open the project’s SQL Editor, paste the whole file in and press Run. It creates the tables, the policies and the post_media bucket in one go. Running it again later is safe — every statement only adds what is missing — and it is how you update a service set up from an older file.
  3. Copy the publishable key. Project Settings → API: the value starting with sb_publishable_. Do not copy the secret key, and do not put it anywhere a phone could read it.
  4. Connect your own phone with the URL and key as described above, then invite your members.

Updating a service set up before October 2026. The October schema makes private-message and steward mailboxes readable only through a request for one exact address, and caps how many drops an address takes per day. Run the latest file again after your members have updated the app: versions of the app from before October 2026 cannot collect private messages from a service that has it. The current app works with the service either way.

When it does not work

  • “Will not carry GIFs / this kind of file yet.” The service’s schema is older than the app. Run the latest schema file again; it only adds what is missing.
  • Private messages through the service never arrive. The same cause: a service set up before September 2026 lacks the private-message mailbox. Run the latest schema file again.
  • Videos over a certain size wait for ever. Supabase’s free tier caps each file at 50 MB, and that cap overrides a larger bucket setting. The app allows 100 MB, so a 60 MB video is refused and waits. Under 50 MB is fine.
  • Nothing arrives, no error. A service running an old schema looks, to its members, exactly like one where nobody has posted. The Check button on a saved service tells the two apart: it asks the service what it will actually carry and names whatever is missing, with the fix. It writes nothing.

What the service can and cannot see

Everything you publish into a community topic is readable by the service, because carrying it is its job. Private messages are sealed to their recipient before they leave your phone; the service carries them without being able to read them. Your private entries, drafts and keys never reach it at all. The privacy policy says the same thing at greater length.