Is there autocomplete for Slack?
The short version: Yes. Opsis writes your next line wherever you type: Slack, Gmail, Outlook, Teams, Notion, Google Docs and AI chats like Claude and ChatGPT. Press Tab to keep it. It can also draft a whole reply from a few notes, using facts from your own work: what's on your screen, the apps you connect (Gmail, Calendar, Drive, Slack, Notion, GitHub, Linear, Outlook) and your history. In Slack that means a suggested continuation of your sentence in the message box, and Tab to keep it. Opsis runs on Mac and Windows. It's free to start, and Pro is $15 a month.
Slack itself doesn't finish your sentences while you type. Its AI features lean towards catching up on what you missed, such as summaries and search (check what your plan includes). Browser extensions and workflow tools can draft a reply. as of November 2026, a handful of searches turned up no other product that offers Tab-to-keep completion in the Slack message box on both Mac and Windows.
How it compares.
Ways to get help writing Slack messages, as of November 2026
| Option | How it helps | Where it works | Uses your own work for facts |
|---|---|---|---|
| Opsis | Finishes your next line as you type. Tab keeps it. Can draft a full reply from notes. | Slack, plus Gmail, Outlook, Teams, Notion, Google Docs and AI chats. Mac and Windows. | Yes: your screen, connected apps and history. |
| Slack's built-in AI | Summaries, recaps and search over your workspace. Plan-dependent. | Inside Slack only. | Slack data only. |
| Reply bots (Runbear Inbox Agent, Zapier and n8n flows) | Draft a reply when you are mentioned. Runbear shows the draft only to you in the thread. | Inside Slack, after a trigger. Not as-you-type. | Connected tools, depending on how you set it up. |
| ChatGPT or Claude in another window | Write a reply from whatever you paste in. | Anywhere, by copy and paste. | Only what you paste. |
Swipe the table to compare
Figures and shutdown dates come from the sources at the bottom, or from this site's own product copy. We don't invent competitor features.
Who it's for.
People who spend the day answering in Slack: founders, operators, customer success, support, recruiters and anyone who types the same kind of reply fifty times a week.
Your data.
Opsis only follows the apps you share. Private windows and password managers are never recorded. When assistance is on, the text it needs is processed in the cloud with your consent, encrypted in transit and at rest, with zero data retention at our AI providers. Opsis isn't a screen recorder. You can pause, disconnect an app or delete your history whenever you like. Read the privacy policy · How Opsis handles data.
What it looks like in practice
Someone asks when the proposal will be ready. You start typing "It should be" and Opsis offers the rest, using what it can see: the thread, the doc you have open, the calendar. Tab keeps it. Keep typing and it goes away.
For longer replies you jot a few notes ("Thursday, needs legal sign-off, sorry for delay") and Opsis turns them into a full message. You read it before it goes anywhere. Opsis never sends a message for you.
Where it falls short
It is a draft. If the thread is missing the key fact, the suggestion can be wrong, so read it before you send. It also only sees apps you chose to share.
FAQ
Does Slack have autocomplete?
Not for finishing your sentences as you type. Slack has its own AI features for summaries and search, which depend on your plan. Opsis adds the as-you-type layer on top of Slack on Mac and Windows.
Does Opsis send messages for me?
No. It writes text into the box and you press Enter yourself. Tab keeps a suggestion. Undo is there if you change your mind.
Is my Slack data uploaded?
When assistance is on, the text Opsis needs is processed in the cloud with your consent, encrypted in transit and at rest, with zero data retention at our AI providers. You choose which apps are shared and can pause or delete your history at any time.