Local-first substrate

Fertile ground for
local-first apps.

Loam is the soil your apps grow in — a shared delivery node and an offline Bluetooth mesh, so many people can edit the same thing and always converge. Online, on the same Wi-Fi, or just in the same room.

See the substrate Read the code

Sync that doesn’t need the cloud to keep a promise.

Most collaborative apps stop the moment the internet does — even when the people who want to sync are standing next to each other. Loam is built the other way around: every write is a sealed event that any device can carry, over any pipe.

Apps don’t manage servers, sockets, or merge conflicts. They append events; Loam moves them and folds them into the same state on every device — a CRDT that can’t lose a write and a transport that reaches for Wi-Fi, the wider network, or Bluetooth, whichever is there.

What grows here

Apps rooted in the same ground.

Each one is just multi-writer state over Loam — no backend of its own, offline by default, yours on your devices.

Kym

Know Your Money — local-first, zero-based budgeting a household shares. No bank login, no server.

budget · household

Scala

Secure CALendar — a shared calendar rebuilt on Logos; devices converge offline, each calendar signed by your own key (Keycard optional).

calendar · has a site ↗

Qaku

Live Q&A for a room — ask, upvote, answer — even on a saturated conference network.

q&a · events

Perun

Privacy-first run tracker — background capture plus analytics, syncing your routes over Loam.

tracker · gps

The ground beneath

Three layers of substrate.

Dig down from an app and this is what holds it up — the node it talks to, the engine that makes everyone agree, and the transport that reaches the next device by any means.

      Topsoil01 · node
loam xyz.vpavlin.loam
The device-wide shared delivery node. One shared Logos node per phone, shared by every Loam app behind a consent gate — so ten apps don’t each run ten radios. Also hosts the Bluetooth mesh for the whole device.

      Subsoil02 · convergence
loam-sync
The agreement engine. An event-log CRDT with HLC ordering and range-based set reconciliation: every device folds the same events into the same state, in any arrival order, with no lost writes and no merge conflicts to resolve.

      Bedrock03 · reach
loam-transport
The reach. A shared node over the Logos network, plus a Bluetooth-LE mesh bearer that carries the same sealed writes phone-to-phone when there’s no internet at all. One frame, whichever pipe is there; the sync layer dedups the rest.

    

How it holds together

Four properties, all the way down.

Offline by default

No server is in the critical path. A device works alone, holds its own history, and syncs whenever a peer appears. The network is an optimization, not a requirement.

Room-scale mesh

When the internet is gone or the venue Wi-Fi is drowning, nearby devices form a Bluetooth mesh and keep syncing directly — then heal back to the wider network the moment it returns.

Convergent, not coordinated

Every write is a commutative event folded by a CRDT. Two people editing the same thing offline both keep their change; the log converges to one state everywhere.

Yours, sealed

Data lives on your devices as sealed bytes. The transport — Logos or Bluetooth — only ever moves ciphertext; it never needs to understand what it carries.

Read the ground

See every node — even the offline ones.

The failures that matter happen off the network — a dead zone, a basement, a room on Bluetooth alone — where you can’t watch live. So each node keeps its own diagnostics and, the moment it reaches the fleet again, flushes them — sealed — to a telemetry topic. A collector turns them into Prometheus metrics, so phones and desktop nodes sit side by side in Grafana, the offline stretch and all. Opt-in, ciphertext-only, and off by default.

Buffered offline

A node records its own health to disk while it’s cut off, then drains the backlog to the fleet when a path reappears — so the offline story survives, not just the moments you happened to be watching.

Sealed & opt-in

Snapshots are encrypted; the topic and key derive from one shared secret, so only a holder can locate or read them. Nothing ships unless you turn it on.

One pane, every node

Android and Basecamp publish the same shape over delivery; the hub decodes it into /metrics labelled by device and platform — compare a phone against a desktop node in one dashboard.

Watch it from the hub

The collector subscribes the telemetry topic and serves Prometheus metrics — point Grafana at it:

logos-hub telemetry loam --secret <shared> --port 9109

Get started

Open the ground up.

Everything is open and self-hostable. Start with the substrate, or install the shared node and let an app bind to it.

vpavlin/loam The shared delivery node + BLE mesh app. vpavlin/loam-transport Shared Logos node + Bluetooth mesh bearer. vpavlin/loam-sync Event-log CRDT · HLC · set reconciliation.

Install the Loam node

Public F-Droid repo at apps.vpavlin.xyz (also reachable over the home LAN or the mesh). Add it in F-Droid — the fingerprint pins it as its own repo:

https://apps.vpavlin.xyz/fdroid/repo?fingerprint=2373710A76ACB09F287F053E99E533F9D3685529C44E9027CDBC79B1DC0C9105

Fertile ground forlocal-first apps.