Backpack

Backpack

What it does: Installs Android apps from repositories that live in Logos Storage

Stage: Prototype

Licence: MIT or Apache-2.0

Build · Use · Code · User reviews

Verified on 4 November 2026 against README and commit of 2 November 2026.

Backpack is an Android app store by the GitHub user vpavlin whose repositories live in Logos Storage, with update notes carried over Logos Messaging (Logos Delivery).

What it does

• It works as "a tiny F-Droid" (F-Droid is an open-source Android app store). The APKs, their icons and the repository index are all Storage objects fetched by CID (content identifier).
• Publishers get a desktop command-line tool, backpack, that uploads APKs and icons to a Storage node, publishes a signed index and prints the repository link.
• Users get an Android app, with Logos Storage running on the phone, that adds a repository from a backpack:// link, lists its apps, and installs or updates them.
• Each new index is announced by a small signed note on a Logos Delivery topic. HTTPS addresses in the link can also carry the note, though that setting is off by default.
• Backpack checks the signature and sequence number of every note and index, the SHA-256 of every APK, and that each APK's signing certificate matches the pinned one.
• An existing F-Droid repository can be imported, but only through a verified index.
• A setting lets app updates install automatically.

Stage: Prototype. The README states no stage, so the page lists it as Prototype on the strength of its working code. The install steps cover the publisher CLI, and the Android app is built from source. The README's list of limits says Delivery needs Loam, a separate app that runs a shared node on the phone, and that there is no key rotation yet. The same list says downloads from the publisher's server run at 200 to 500 KB/s and only arm64 phones are supported. The README does not say whether it is an official Logos project.

Use it

1. Publisher: in cli/, run npm install.
2. Run ./backpack.mjs init --name "My backpack". This creates the repository key in ~/.backpack/default/key.pem, which needs backing up.
3. Set where the update note is read and written with ./backpack.mjs config, then add apps with ./backpack.mjs add path/to/app.apk or ./backpack.mjs import-fdroid.
4. Run ./backpack.mjs publish. It uploads the index to Storage, sends the note and prints a link and a QR code.
5. On the phone, open the printed backpack:// link or scan the QR code once. After that the phone follows the repository on each app start or pull-to-refresh.

Delivery on the phone needs the Loam app. Without it, and with the web setting off, a repository only moves forward when a newer link is opened.

Build it

• git submodule update --init fetches loam-transport, and cd mobile && npm install follows it.
• native/logosstorage/build-jni.sh builds the JNI glue for libstorage.
• The app builds with npx expo prebuild --platform android --clean, then ./gradlew assembleRelease in mobile/android. The README gives the full sequence, including the Android SDK path and a lint setting.

Releases

The latest tag is basecamp-arm64-0.6.4, dated 3 November 2026, on the feat/basecamp-private-follow branch. basecamp/backpack_ui/metadata.json gives backpack version 0.6.2 and basecamp/backpack_core/metadata.json gives backpack_core version 0.6.2. The README does not describe these Basecamp packages.

See also

• Basecamp
• Tools
• Logos Storage
• Logos Messaging

Sources

• backpack README, GitHub, last commit 2 November 2026
• basecamp/backpack_ui/metadata.json and basecamp/backpack_core/metadata.json, GitHub
• backpack tags, GitHub

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