Does Slack work offline?

No. Slack has no true offline mode. On desktop/web, you can't do anything without internet. On iOS, you can only view previously cached messages (read-only). In 2025, Slack added offline draft mode which lets you write drafts offline, but you still can't search, read uncached messages, or access files.

Does Microsoft Teams work offline?

Partially. Teams has a limited offline mode that gives you read-only access to chats and channels you've accessed in the last 30 days. You cannot send messages, search, access SharePoint files, or use any integrated apps while offline.

What is a local-first app?

A local-first app stores your data on your device first, then syncs in the background. This means full offline access—you can read, write, and search without internet. When you reconnect, changes sync automatically. Examples include Linear, Obsidian, and Dock.

Why Slack and Teams Don't Work Offline (And Why It Matters)

You're on a plane, in a tunnel, or at a conference with terrible wifi. Your team chat is useless.

January 2026 · 6 min read

The Problem Nobody Talks About

Slack and Microsoft Teams are the backbone of modern work communication. Billions of messages flow through them daily. But try to use either one without internet and you'll hit a wall.

Slack: Can't send messages. Can't search. Can barely read old conversations.

Teams: Similar story. Read-only access to recent chats—if you're lucky.

For tools that claim to "keep teams connected," they fall apart the moment your connection does.

Slack's Offline Limitations

What Actually Happens

On Desktop/Web:

No offline mode at all
Lose connection = spinning loader
Can't read, can't search, can't do anything

On Mobile (iOS):

Can view previously cached messages (read-only)
Can't send new messages
Can't search your history
Cache is limited and unpredictable

The 2025 "Fix" - Offline Draft Mode:

Slack finally added offline drafts in 2025
You can write a message offline
It queues and sends when you're back online
That's it. That's the whole feature.

You still can't search old messages, read channels you haven't recently viewed, or access files.

Real-World Impact

On a flight: 5 hours of "work time" where you can't reference any previous conversations.

Spotty conference wifi: Miss real-time updates, can't catch up on what you missed.

Remote location: Client site with bad internet = you're cut off from your team.

Microsoft Teams' Offline Limitations

What You Get

Read-only access to "recent" chats and channels
"Recent" means accessed in the last 30 days
Messages must already be cached locally

What You Don't Get

Can't send messages
Can't search
Can't access SharePoint files
Can't use any integrated apps
Can't join or view recordings

The Sync Problem

Unlike Outlook (which has full offline via OST files), Teams doesn't maintain a complete local cache. Microsoft's own documentation admits:

"Teams' synchronization model does not create a local cache of all its message data."

So even the offline "reading" is hit-or-miss depending on what you've recently accessed.

Why Are They Built This Way?

Cloud-First Architecture

Both Slack and Teams were built in the cloud era with a simple assumption: you'll always be online.

Every message goes to their servers first. Your device is just a window into their cloud. They didn't build local-first because they didn't think they needed to.

The Lock-In Effect

When your messages only exist on their servers:

You can't easily leave
You can't access data without paying
They control your team's institutional memory

This is the same reason Slack hides messages after 90 days on free plans. Your data is leverage.

What "Local-First" Means

There's a different way to build software. It's called local-first.

The principle: Your data lives on your device first. Sync happens in the background.

What this enables:

Full offline access—read, write, search
Instant performance (no round-trips to servers)
You own your data
Works on planes, trains, basements, wherever

Apps built this way: Linear (issue tracking), Obsidian (notes), Figma (partial—local caching).

Team chat has been stuck in the cloud-first era. Until now.

The Comparison

Feature	Slack	Teams	Dock
Read offline	Limited	Limited	Full
Write offline	Drafts only	No	Full
Search offline	No	No	Full
Data ownership	Cloud	Cloud	Local
Works on a plane	Barely	Barely	Fully

Ready for team chat that works anywhere?

Dock is built local-first. Full offline access—read, write, search. Your messages, always available.

→ Join the waitlist

Why This Matters More Than You Think

Remote work is everywhere. Not everyone has perfect fiber internet.

Travel is back. Planes, trains, client sites with terrible wifi.

Reliability matters. When Slack goes down, so does your team. Local-first apps keep working.

Your data is yours. You shouldn't need permission (or a subscription) to access your own conversations.

Bottom Line

Slack and Teams are powerful tools—when you're online. But their cloud-first architecture means you're always one bad connection away from being cut off.

If your work doesn't stop when wifi does, your tools shouldn't either.

Team chat that works offline

Dock works offline, online, and everywhere in between. No spinning loaders. No "drafts only."

→ Get on the Dock waitlist

Last updated: January 2026