Works without internet
Designed for labs, offices, classrooms, and field teams that share one local network but cannot depend on cloud services.
Open-source local-first collaboration
Share files and messages with your team, even when the internet is gone.
LocalSlack is a cute, fast desktop app for same-network teams. It discovers nearby devices with mDNS, sends data directly peer to peer, and keeps collaboration private inside your LAN.
- 67ms
- median LAN message delivery
- 38 MB/s
- 100 MB file transfer average
- 0 cloud
- no accounts, telemetry, or servers
Why it exists
Cloud tools are wonderful, until your network reality is not.
LocalSlack focuses on the surprisingly common moment when a team is physically close, has Wi-Fi, and still needs collaboration to keep moving without the outside internet.
Zero-config discovery
Devices advertise and discover each other through Multicast DNS using the _localslack._tcp.local service.
Direct peer transfer
Each desktop app hosts its own Axum HTTP server, so files, clipboard text, and channel events move device to device.
Offline-capable history
Messages, transfers, settings, favorites, and event logs persist locally through the embedded Sled database.
Integrity checked
Transfers are streamed with SHA-256 verification, giving users confidence that received files are complete.
Privacy by locality
No accounts, telemetry, analytics, external identity provider, or cloud storage sits between nearby teammates.
How it is built
A small desktop app that quietly becomes a LAN collaboration node.
The website mirrors the app architecture: simple surfaces, direct connections, and each responsibility split into clear pieces.
Desktop shell
Tauri v2 keeps the app lightweight while Rust handles the network-heavy work.
Frontend
React and TypeScript compose the send, receive, channels, history, and settings workflows.
Peer API
Axum exposes upload, clipboard, channel event, asset, and cancel endpoints on each device.
Discovery
mDNS broadcasts the device name and bound HTTP port across the LAN.
Persistence
Sled stores event logs, transfer records, preferences, allow/block lists, and favorite peers.
Control
Users can choose receive behavior, save paths, visibility, and trusted devices locally.
Research backed
Built like a product, documented like a system paper.
The IEEE-style paper explains the design problem, protocol choices, synchronization model, security tradeoffs, and measured performance of LocalSlack across multiple LAN devices.
LocalSlack IEEE Paper v1
8 pages, system design and evaluationMessage delivery stayed under the real-time perception threshold in LAN tests.
Large files completed successfully with no detected corruption.
Disconnected peers reconciled event logs after reconnecting.
SHA-256 file checksEventual consistencyLocal data ownership