Zero configuration

Up and running in 60 seconds

No server to set up, no IT department required. If two PCs share a network, they can chat.

Install on every PC

Run the installer on each computer in your office. Firewall rules are configured automatically.

They find each other

Machines on the same LAN or Wi-Fi discover each other automatically within seconds. No IP addresses to type.

Chat, share, assign

Message coworkers, drag-and-drop huge files at LAN speed, create groups, assign tasks — even when the internet is down.

Everything you expect

A modern messenger. Minus the internet.

The familiar experience of Telegram or Zalo — running entirely inside your walls.

Automatic discovery

Everyone running ChatLAN on your network appears instantly — with live online status.

Files at LAN speed

Send gigabyte files directly PC-to-PC at 100+ MB/s. Resume if interrupted, verified by checksum.

Group chats

Serverless groups with @mentions, replies, pinned messages and per-member delivery ticks.

Encrypted by default

Every connection is TLS-encrypted with per-device keys. Impersonators are blocked automatically.

Native notifications

Windows toasts, system tray, unread badges and per-chat mute — @mentions always break through.

No server. No accounts.

Nothing to host, nothing to subscribe to, nothing to sign up for. Install and chat.

More than chat

It runs your workday, too

Lightweight work tools built right into the conversation — because tasks shouldn't drown in the chat scroll.

Tasks in chat

Assign work with a deadline right in the conversation. "My Tasks" collects everything assigned to you, overdue in red.

Polls

Decide the meeting time (or the lunch spot) in seconds with live vote counts.

Reminders

Right-click any message → "Remind me". Survives restarts, fires even from the tray.

Team notebook

A shared note per group for the Wi-Fi password, procedures and everything the team keeps re-asking.

Pins & mentions

Pin what matters, @mention who matters. Pinned bar on top, mention badges that pierce mute.

Birthday reminders

Opt-in birthdays with a 🎂 next to the name and a gentle nudge to the whole office — once a year, never creepy.

New · Private AI

AI that never leaves your office

ChatLAN now ships with an AI assistant built the same way as everything else here — private by default, and just as happy running with zero internet connection.

Built-in AI, zero setup

A small language model runs directly inside ChatLAN — no server, no cloud account. Download it once (about 1.5 GB) and it keeps working offline from then on, even on an air-gapped network.

Translate any message instantly

Right-click a message to translate it into your language on the spot, streamed in as it's written — handy the moment a coworker types in a language you don't read.

Tasks and events, spotted automatically

Type "let's meet Thursday 3pm" and ChatLAN quietly suggests turning it into a task or event — one click to confirm, never created without asking first.

Search by meaning, not just keywords

Can't remember the exact words? Semantic search surfaces messages that mean what you're looking for, right alongside your regular keyword results.

Pull text out of any image

Right-click a screenshot or photo to extract its text instantly — runs entirely on your PC, reading Vietnamese and English automatically.

Off by default. Always your choice.

Pick Built-in, LAN, or Cloud AI — or leave it off entirely. Cloud mode is clearly disclosed and can be locked off company-wide by an admin.

Private by architecture

Your messages never leave the building

No cloud, everMessages travel directly between PCs on your LAN. There is no server — ours or anyone else's — that could store, scan or leak them.
TLS on every connectionChat and file channels are encrypted with per-device RSA-2048 keys generated on first run.
Trust on first useLike SSH: each device's key fingerprint is remembered. If a machine suddenly changes keys, it's blocked and you're warned.
Your data stays yoursHistory is stored locally on each machine. Uninstall and it's gone — no accounts to delete, no exports to request.

FAQ

Questions, answered

How can it work without the internet?

ChatLAN talks directly between computers over your local network (LAN or Wi-Fi router). The internet connection is simply never used — if your office network is up, ChatLAN is up.

Two PCs can't see each other. What do I check?

Open ☰ → Network diagnostics in the app — it checks your IP, firewall rule and gateway automatically. The most common causes: the PCs are on different subnets/VLANs, or the Wi-Fi router has "AP/Client Isolation" enabled (turn it off in router settings). You can also connect manually by IP from the ☰ menu.

Does any of my data leave the network?

No. There are no ChatLAN servers. Messages, files and history exist only on the machines in your network, encrypted in transit with TLS.

Windows SmartScreen warns me about the installer.

The current build isn't code-signed yet (signing certificates are on the roadmap). Click "More info" → "Run anyway". The installer only adds the app and a firewall rule; you can verify the rule under Windows Firewall → "ChatLAN".

Is it really free?

Yes — chat, groups, LAN file transfer and every work tool are 100% free, with no machine limit and no subscription. A plugin marketplace is planned for later, handled entirely inside the app for teams who want optional add-ons — the core messenger stays free.

No internet.
Still chatting.