WHY I BANNED SLACK ON MY TEAM
Async-first communication increased deep work by 3x. The team hated it for 2 weeks. Then they never went back.
Real-time chat is the enemy of deep work. A channel that expects an answer in minutes turns every engineer into a monitor — one eye always on the unread badge. That's not collaboration — it's a context switch your brain pays for every few minutes, and you can't solve a hard problem inside it.
So, leading an engineering team, I did the unthinkable. I banned Slack.
We went fully async. Documentation first. Long-form writing. Code comments. Pull request descriptions that actually explain the decision. The rule was simple: if it's urgent, call. If it's not, write it down and wait.
What I actually measured
A claim like "3x more deep work" is worthless without a definition of deep work. So we defined it before we changed anything, and measured the same way for six months on either side of the switch.
We called the unit a Focus Block Hour (FBH): a continuous block of at least 90 minutes, no meetings, fewer than two interruptions, with verifiable technical output at the end. Measured at the team level, in aggregate — no screenshots, no keylogging, no per-person surveillance. You don't need to spy on people to count whether the conditions for focus existed. You need an honest definition and the discipline to apply it.
Before the ban: 1.6 FBH per developer per day. Six months after: 4.9. Roughly a 3x increase in the actual raw material of engineering — not hours worked, hours of uninterrupted thinking.
The first two weeks were ugly
I won't pretend the transition was clean. For about two weeks the team hated it. People felt disconnected. They felt slow. The dopamine of the instant reply was gone, and its absence felt like silence in an empty office.
Then something shifted. The questions that used to fire off into a channel — and derail whoever was in flow — got written down. Many of them answered themselves in the writing. The rest got better answers, because the person replying had time to think instead of react.
Nobody asked to bring Slack back.
The connection was noise
The objection to async is always the same: we'll lose connection. We didn't. We lost interruption and had been calling it connection.
Real-time chat is coordination overhead, and overhead compounds quietly until it stalls the whole team. Strip it out and the connection that remains is the real kind: built from shipping things together, not from reacting to each other all day.
Ban the channel. Protect the block. Ship the work.