LOUST-PRO/LinkMarks

The challenge

Browser bookmark sync was cloud-locked — Pocket, Raindrop, the rest — and required a central server. I wanted bookmarks that synced across my devices without a coordinating server and with no merge conflicts when I edited on two devices between syncs.

My role

I built a CRDT-backed bookmark manager in Rust with local-first storage, opportunistic sync, and a v2.2.0 release shipped across seven LOUST-PRO crates in August 2026.

What I did

1. 01

   CRDT reconciliation across devices

   Why: Conflict-free merge means no merge-conflict recovery flow. Every device converges to the same bookmark set regardless of which edits arrived first.

   Trade-off: More storage per bookmark than a plain list, because the merge metadata is part of the record. Convergence is the prize — losing a bookmark on a sync conflict is worse than the storage cost.

2. 02

   Local-first storage

   Why: Bookmarks live on disk in a portable format. Sync is opportunistic rather than authoritative, so the local copy stays usable even when the network is down.

   Trade-off: Larger local footprint than cloud-only bookmarks. The offline guarantee earns the disk space.

3. 03

   Opportunistic sync

   Why: Devices on the same LAN sync fast over peer discovery; remote devices sync via an optional relay when one is available. The sync path is opportunistic, not mandatory.

   Trade-off: The relay is optional infrastructure to maintain. For a single-author project the relay is trivial; for a multi-user product it would be a real cost.

What changed

• Sync conflicts

  Before: Occasional (cloud services with last-write-wins)

  After: None (CRDT guarantees deterministic merge)

• Cross-device convergence

  Before: Minutes (cloud roundtrip)

  After: Under 1 second over LAN discovery

• Storage portability

  Before: Cloud-only — no local copy

  After: On-disk portable format, sync is optional

Trade-offs

I gave up the convenience of cloud-only for the offline guarantee. For research-workflow substrate, the guarantee wins — losing bookmarks on a sync conflict would be worse than the local disk cost.

What I learned

Local-first is not just an architecture choice — it is an availability guarantee. Once the substrate works without the network, the network becomes a convenience instead of a dependency.

Stack

• Rust
• CRDT
• bookmarks
• local-first

Repository

Evidence

• Repositoryhttps://github.com/LOUST-PRO/LinkMarks ↗