Slack Recurring Messages Scheduler

A Go CLI tool to schedule Slack messages with support for recurring schedules.

Demo

Full Video on YouTube: https://youtu.be/ZcLI_l6oBdw

Sorry for the lack of color in this clip. I used ffmpeg to compress this clip from the full video above into a gif and had to choose between fps, resolution, and color
-> I chose resolution for legibility.

./slack-scheduler help output:

A CLI tool to schedule Slack messages with support for:
- One-time scheduled messages
- Recurring messages (daily, weekly, monthly)
- Specific days of the week for weekly schedules
- Full Slack formatting support (@mentions, #channel links, emoji, etc.)

Messages are scheduled using your system's local timezone.

IMPORTANT: @channel, @here, and @everyone mentions are automatically converted
to the proper Slack API format to ensure notifications are sent.

Usage:
  slack-scheduler [flags]
  slack-scheduler [command]

Examples:
  # Send a one-time message
  slack-scheduler -m "Hello team!" -c general -d 2025-01-17 -t 14:00

  # Send weekly on Fridays until end date (start date defaults to today)
  ./slack-scheduler -m "Weekly reminder!" -c general -t 14:00 -i weekly --days fri -e 2025-04-01

  # Send on Monday and Friday at 9am for 8 occurrences
  ./slack-scheduler -m "Meeting happening now!" -c engineering -d 2025-01-13 -t 09:00 -i weekly -n 8 --days mon,fri

  # @channel, @here, @everyone, @mentions work
  # So do #channel mentions:
  ./slack-scheduler -m "@channel Hey, please check #meetings." -c general -d 2025-01-17 -t 09:00

Available Commands:
  completion  Generate the autocompletion script for the specified shell
  delete      Delete scheduled messages
  delete      Delete scheduled messages
  help        Help about any command
  init        Create a credentials template file
  list        List all scheduled messages
  modify      Modify scheduled messages

Flags:
  -c, --channel string    Channel name or ID to send to
  -n, --count int         Max number of times to send (0 = unlimited, use --end-date to limit)
  -d, --date string       Start date (YYYY-MM-DD)
      --days string       Days of week for weekly schedule (comma-separated: mon,tue,wed,thu,fri,sat,sun)
  -e, --end-date string   End date (YYYY-MM-DD). Recurrence stops on or before this date
  -h, --help              help for ./slack-scheduler
  -i, --interval string   Repeat interval: none, daily, weekly, monthly (default "none")
  -m, --message string    Message to send (supports @mentions, #channel links, emoji, Slack formatting)
  -t, --time string       Time to send (HH:MM, 24-hour format, local time)

Use "./slack-scheduler [command] --help" for more information about a command.

Features

• Schedule one-time messages
• Recurring messages (daily, weekly, monthly)
• Specific days of the week for weekly schedules
• Full Slack formatting support (@mentions, #channel links, emoji, etc.)
• @channel, @here, @everyone mentions that actually send notifications (automatically converted to Slack API format)
• #channel links that are clickable (automatically converted to Slack API format)
• Message groups for easy batch management
• Modify scheduled messages (change channel, message, time, etc.)
• Uses your system's local timezone

Installation

# Clone the repo
git clone https://github.com/daggerpov/slack-recurring-messages-scheduler.git
cd slack-recurring-messages-scheduler

# Build
make build

# Or install globally
make install

Project Structure

This project follows the Go standard project layout:

.
├── cmd/
│   └── slack-scheduler/    # Main application entry point
│       ├── main.go
│       └── main_test.go
├── internal/               # Private application code
│   ├── config/             # Configuration & credentials handling
│   ├── scheduler/          # Scheduling logic
│   ├── slack/              # Slack API client wrapper
│   └── types/              # Shared type definitions
├── go.mod
├── go.sum
├── Makefile
└── README.md

Setup

1. Create a Slack App

1. Go to Slack API Apps
2. Click "Create New App" → "From scratch"
3. Name it (e.g., "Message Scheduler") and select your workspace

2. Configure Permissions

1. Go to "OAuth & Permissions" in the sidebar

2. Under "User Token Scopes", add:

   • chat:write - Send messages as yourself
   • channels:read - Read channel info (to resolve names)
   • groups:read - Read private channel info

3. Click "Install to Workspace" and authorize

3. Get Your Token

1. After installing, copy the "User OAuth Token" (starts with xoxp-)
2. Create a credentials file:

# Create template
./slack-scheduler init

# Or manually create .slack-scheduler-credentials.json
echo '{"token": "xoxp-your-token-here"}' > .slack-scheduler-credentials.json
chmod 600 .slack-scheduler-credentials.json

Usage

./slack-scheduler [flags]

Required Flags

Flag	Short	Description
--message	-m	Message to send (supports @mentions, #channel links, emoji, formatting)
--channel	-c	Channel name or ID
--date	-d	Start date (YYYY-MM-DD)
--time	-t	Time to send (HH:MM, 24-hour, local time)

Optional Flags

Flag	Short	Default	Description
--interval	-i	none	Repeat interval: none, daily, weekly, monthly
--count	-n	1	Number of times to send
--end-date	-e		End date (YYYY-MM-DD). Recurrence stops on or before this date
--days			Days of week (comma-separated: mon,tue,wed,thu,fri,sat,sun)
--group	-g		Name for this message group (for easier management)

Examples

One-time message:

./slack-scheduler -m "Hello team!" -c general -d 2025-01-17 -t 14:00

Every Friday at 2pm for 4 weeks:

./slack-scheduler \
  -m "Weekly reminder: Please submit your timesheets!" \
  -c general \
  -d 2025-01-17 \
  -t 14:00 \
  -i weekly \
  -n 4

Monday and Friday at 9am for 8 occurrences:

./slack-scheduler \
  -m "Standup time! :coffee:" \
  -c engineering \
  -d 2025-01-13 \
  -t 09:00 \
  -i weekly \
  -n 8 \
  --days mon,fri

Daily reminder for 5 days:

./slack-scheduler \
  -m "@channel Don't forget to check your PRs" \
  -c dev-team \
  -d 2025-01-13 \
  -t 10:00 \
  -i daily \
  -n 5

Monthly report reminder:

./slack-scheduler \
  -m "Monthly metrics report due this week" \
  -c analytics \
  -d 2025-01-01 \
  -t 09:00 \
  -i monthly \
  -n 12

Sundays until April 10th (stops at last Sunday on or before end date):

./slack-scheduler \
  -m "Weekly Sunday update" \
  -c team-updates \
  -d 2025-01-05 \
  -t 10:00 \
  -i weekly \
  --days sun \
  -e 2025-04-10

Daily messages until a specific date:

./slack-scheduler \
  -m "Daily standup reminder" \
  -c engineering \
  -d 2025-01-13 \
  -t 09:00 \
  -i daily \
  -e 2025-01-31

Message Formatting

The message field supports full Slack formatting:

• Mentions: @username, @channel, @here, @everyone
• Channel links: #channel-name (automatically converted to clickable links)
• Emoji: :thumbsup:, :rocket:, :coffee:
• Bold/Italic: *bold*, _italic_
• Links: <https://example.com|Click here>
• Code: `code`, ```code block```

@channel, @here, @everyone Notifications

Unlike raw Slack API calls, this tool automatically converts broadcast mentions to the proper Slack API format:

• @channel → <!channel> (notifies everyone in the channel)
• @here → <!here> (notifies active members)
• @everyone → <!everyone> (notifies everyone in the workspace)

This means you can write natural messages like:

./slack-scheduler -m "@channel Don't forget standup!" -c general -d 2025-01-17 -t 09:00

And recipients will actually receive notifications, just like when you type @channel in Slack directly.

Note: For @channel/@here/@everyone to work, you must use a User OAuth Token (xoxp-...), not a Bot Token (xoxb-...).

#channel Links

Channel references are also automatically converted to clickable Slack links:

• #general → <#C1234567|general> (clickable channel link)
• #dev-team → <#C7654321|dev-team> (clickable channel link)

Example:

./slack-scheduler -m "Please post updates in #engineering" -c general -d 2025-01-17 -t 09:00

The #engineering reference will become a clickable link in the message. If the channel doesn't exist, the original text is preserved.

Managing Scheduled Messages

List Scheduled Messages

View all messages you've scheduled via the API:

# List all scheduled messages
./slack-scheduler list

# List scheduled messages for a specific channel
./slack-scheduler list -c general

Delete Scheduled Messages

Cancel scheduled messages:

# Delete a specific scheduled message by ID
./slack-scheduler delete -c general --id Q0A7Z0QMWAF

# Delete all messages in a group
./slack-scheduler delete --group "standup-reminders"

# Delete ALL scheduled messages in a channel
./slack-scheduler delete -c general --all

Modify Scheduled Messages

Change attributes of existing scheduled messages. Since the Slack API doesn't support updating scheduled messages directly, this command deletes and recreates them with the new parameters.

# Change the channel for all messages in a group
./slack-scheduler modify --group "standup" --channel new-channel

# Change the message text for a group
./slack-scheduler modify --group "standup" --message "New message text @channel"

# Change the time for all messages in a group
./slack-scheduler modify --group "standup" --time 10:00

# Modify a single scheduled message
./slack-scheduler modify --id Q0A7Z0QMWAF --channel general --message "Updated text"

Message Groups

When you schedule recurring messages, they're automatically saved as a "group" for easier management. You can also specify a custom group name:

# Create a group with a custom name
./slack-scheduler -m "Standup time!" -c engineering -d 2025-01-13 -t 09:00 -i weekly -n 8 -g "standup-reminders"

# List all groups
./slack-scheduler list --groups

# Modify all messages in a group at once
./slack-scheduler modify --group "standup-reminders" --channel new-engineering

# Delete all messages in a group
./slack-scheduler delete --group "standup-reminders"

Groups are stored locally in .slack-scheduler-groups.json and track which scheduled message IDs belong together.

Important: Slack UI Limitation ⚠️ Messages scheduled via the Slack API do NOT appear in Slack's "Scheduled Messages" UI.

This is a Slack platform limitation, not a bug. Here's what this means:

Scheduled via	Visible in Slack UI	Actually sends
Slack app (typing /schedule or clicking schedule)	✅ Yes	✅ Yes
This CLI tool (API)	❌ No	✅ Yes

Your messages ARE scheduled and WILL be sent — you just can't see them in Slack's desktop/mobile app.

To view and manage API-scheduled messages, use:

• ./slack-scheduler list — see all scheduled messages
• ./slack-scheduler delete — cancel scheduled messages

Limitations

• Slack only allows scheduling messages up to 120 days in advance
• Past times are automatically skipped
• API-scheduled messages don't appear in Slack's UI (see above), but they will still be sent on schedule

Credentials File

The credentials file should be in the project directory:

• ./.slack-scheduler-credentials.json

Format:

{
  "token": "xoxp-your-user-oauth-token"
}