How to Set Up a Slack Time-Off Bot (Step by Step)
How to add a time-off bot to Slack: requests by slash command, one-click approvals and a daily who's-out post, plus what it costs.
To set up a Slack time-off bot, connect a leave-management tool to your workspace, map your Slack users to their profiles, and pick a channel for the daily "who's out" digest — after that people request leave with a slash command, managers approve from an interactive message, and balances stay correct automatically. The whole thing takes about ten minutes and needs no code. Below is exactly how to do it, and what to watch for.
Why a Slack bot beats a #timeoff channel
Most teams start with a #timeoff channel and a shared spreadsheet: post "off Thursday", get a thumbs-up, hope someone updates the sheet. It works until it doesn't. There are no real balances, an emoji is not an approval record, clashes are discovered the hard way, and next month's absences scroll out of view.
A proper bot fixes this by keeping a real leave system behind the Slack surface. People never leave Slack, but underneath there are accurate balances, an approval trail, public holidays and reports. If your team lives in Slack, the tracker has to live there too — a tool people have to remember to open is a tool they abandon.
Step 1: Choose a tool with a real Slack integration
The main thing to check is whether Slack is a first-class surface or a bolt-on. A genuine integration lets people request and approve inside Slack, not just receive a notification with a link back to a web app. Absenca's Slack bot is built the first way: the request, the approval and the "who's out" lookup all happen in Slack, while the system keeps the books.
A quick sanity check before you commit to any tool:
- Can someone submit a request from Slack (not just get pinged)?
- Can a manager approve or decline from the message itself, on mobile?
- Is there a who's out command and an optional daily digest?
- Does it sign people in with their existing Slack account — no new password?
- Which plan includes the Slack bot, and does it cost extra on top of that plan?
That last point matters, so here is Absenca's answer: the Slack bot comes with Pro, at no extra charge on top of the plan. The free Starter plan (up to 10 people) runs leave in the web app with Google Calendar and Outlook sync, so you can start free and add the bot when you move to Pro.
Step 2: Install the bot into your workspace
In Absenca, open Settings → Integrations, choose Connect Slack and approve the permissions Slack shows you. An admin can do this in under a minute, once the account is on Pro. The bot needs permission to post messages, respond to slash commands, and open the request dialog — standard scopes for this kind of app.
If your workspace restricts app installs, a Slack admin either installs it directly or approves the request from Slack's app-management screen. Nothing here touches your Slack data beyond what the bot needs to route requests.
Step 3: Match Slack users to their profiles
For approvals to reach the right manager, each Slack user is linked to their person in the leave system. Most people are matched automatically by email on first use; anyone who isn't can be linked in a couple of clicks. This is also where reporting lines come from — a request from an engineer goes to their manager, not to everyone.
If you are rolling this out to a new team, importing your roster first (a CSV of names, emails and departments) makes the matching essentially automatic.
Step 4: Pick your channels and digest
Choose where the daily digest posts — usually a general channel like #team or a dedicated #whosout. Every morning the bot drops a short summary of who is off today and this week, so nobody has to ask. Individual approvals go privately to the relevant manager, so you are not broadcasting everyone's leave to the whole company.
Step 5: Show the team the two commands
Rollout is genuinely two commands:
/absenca leaveopens a request — pick the leave type and dates, see your live remaining balance, submit. Half-days (AM/PM) and different leave types (vacation, sick, parental) are all there./absenca whosoutanswers "who's away today and this week?" on demand.
The manager side is one tap: the request lands as an interactive message; approve or decline from any device. Underneath, the system handles accruals, carry-over caps and expiry, pro-rata for joiners and part-timers, TOIL, blackout periods, and public holidays for 190+ countries — none of which the team has to think about. Approved leave can also sync to Google or Outlook calendars so meeting scheduling reflects reality.
What it costs
Check two things before you decide: which plan includes the Slack bot, and what that plan bills for your team. Both differ a lot between tools. Leave Dates' Slack app, on Essential and Plus, posts a daily who's-off report; it doesn't take leave requests or approvals in Slack.1 Vacation Tracker's Core plan costs $2 and Complete $4 per user per month, with monthly minimums of $50 and $100.2
Absenca is free for up to 10 people, with leave tracked in the web app. The Slack bot comes with Pro: $37.50 a month for up to 50 people, or $33.75 a month billed annually ($405 a year). Pro bills 50 seats at $0.75 a month each whatever your headcount, so any team of 16 to 50 people pays the same $37.50, with no extra charge for the bot. Above 50 people or 2 offices, you configure a Custom Pack and see its price in the app before you pay. You can see the full breakdown on the pricing page.
Common questions
Do people need a separate login? No — they sign in with their existing Slack account, and day-to-day requests and approvals happen entirely inside Slack.
Can managers approve on their phone? Yes — the approval is a tap on the interactive message, from Slack mobile or desktop.
Is the Slack bot free? No. The Slack bot comes with Pro, which is $37.50 a month for up to 50 people. Absenca's free Starter plan covers up to 10 people, with approvals, balances and public holidays in the web app, so you can start free and add the bot by moving to Pro.
A quick legal note: statutory leave entitlements and record-keeping rules vary by country. Software helps you apply your policy consistently, but this is general guidance, not legal advice — check the rules in your jurisdiction.
Live in Slack? Start free with Absenca — free for up to 10 people, no credit card, with the Slack bot on Pro. See the Slack integration in detail, or how it works as a vacation tracker for Slack.