Slack calls feature no longer invite only, is now available on desktop and for iOS and Android devices
A simple, pleasant way to speak with your team — Typing is great. We love typing. And while there are many fine ways to communicate via typing—messaging in channels …
Context & Ripple Effects
By mid-2016, Slack had already spent a year building out its client footprint — the Windows desktop app launched in March 2015, followed by a faster Android app with quicker navigation that June — so making calls available on every one of those surfaces was the natural completion step. What changes today is access: the voice feature drops its invite-only gate, putting live audio inside the same channels where teams already type.
That matters because Slack's identity had been built on text, and this is the moment it commits to voice as a first-class mode rather than an experiment. The related coverage shows where that commitment led: by 2020 Slack was integrating Microsoft Teams calling alongside Zoom, WebEx, and Jabber VoIP, and by 2021 it opened cross-organization Connect DMs — both moves that treat the app as a universal communication layer, not just a chat tool.
First-order effects
- Every Slack user on desktop, iOS, and Android can now start a call without waiting for an invite, making voice a default capability of the product rather than a gated test.
Second-order effects
- Rivals' calling tools become directly comparable inside Slack's interface instead of sitting outside it — pressure that surfaces four years later when Slack ships an app integrating Microsoft Teams calling with Zoom, WebEx, and Jabber VoIP.
Third-order effects
- If voice keeps deepening alongside text, workplace messaging converges into a single hub where chat, calls, and eventually cross-organization contact (as Connect DMs later allow) replace separate point tools for each mode.
The trend: Workplace messaging platforms are steadily absorbing real-time voice and cross-boundary contact, turning chat apps like Slack into all-in-one communication hubs.