Slack Schedule Message: How to Schedule Slack Messages
Slack schedule message is built into Slack: type your message, click the arrow next to the send button and pick a time. To plan Slack posts for several channels alongside your social networks, iHatePosting, an AI social media scheduler for 15 networks with unlimited accounts for $15/month (billed annually), publishes them at the time you set.
Key takeaways
- Slack's own scheduler sits in the message box: on desktop, click the arrow next to the paper-plane icon; on mobile, tap and hold it, then choose a time.
- Messages you schedule in Slack wait under Drafts & sent, in the Scheduled tab, where you can edit or delete them before they go out.
- iHatePosting connects to Slack as an app you install once per workspace. Every channel you pick becomes its own account, so one post can reach several channels.
- A Slack post from iHatePosting holds up to 3,000 characters, with up to 5 images and one video.
- ChatGPT, Claude and other AI agents can schedule the same Slack post for you through iHatePosting's MCP server.
How to schedule a message in Slack
To schedule a message in Slack, write it in the message field, then click the arrow next to the paper-plane send icon and choose a time. On the mobile app, tap and hold the send icon instead. Pressing Enter sends the message straight away, so use the arrow.
- Open the channel, direct message or thread the message is for.
- Type the message and add any files, emoji, mentions or formatting.
- On desktop, click the arrow next to the paper-plane icon. On mobile, tap and hold the paper-plane icon.
- Pick one of the suggested times, or set your own date and time.
To change a scheduled message, open Drafts & sent at the top of the sidebar and select the Scheduled tab. On desktop, hover over a message to see its options. On mobile, tap and hold it to edit, reschedule, send now, cancel or delete it. These steps come from Slack's Help Center article on sending and reading messages (checked November 2026).
Slack schedule message vs. a social media scheduler
Slack's built-in scheduling is the quickest option for a single message in a single workspace. It is written and timed one message at a time, from inside Slack.
A scheduler helps when the same announcement also goes elsewhere. A product launch might go to a Slack channel for your team or community, and to Instagram, LinkedIn, X, Facebook and more for everyone else. With iHatePosting you write it once, adjust the Slack version, and every network publishes from the same calendar. The same approach works for Discord and Telegram communities, and post to all social media at once covers the full workflow.
How to schedule Slack posts with iHatePosting
Connect your Slack workspace
Choose Connect Slack in iHatePosting, approve the iHatePosting app for your workspace, then pick the channels it may post to. Each channel you pick becomes its own account in iHatePosting.
Write your post
Draft the message in the composer. It checks the post against Slack's limits as you type: up to 3,000 characters, 5 images and one video.
Customize it for Slack
Use a per-network text override to give the Slack version its own wording, such as a shorter internal note or Slack formatting, without changing what the other networks get.
Pick a date and time, or let an AI agent schedule it
Choose when it should go out, in your own time zone, or ask ChatGPT, Claude or another connected AI agent to schedule it for you.
Publish
iHatePosting posts to the channel at that time and links the post to the message in Slack. If Slack refuses it, you get the reason in plain words and a one-tap retry.
Slack post tips
Pick the right channels
Public channels just work: the first time iHatePosting posts to one it hasn't joined, it joins the channel and posts. For a private channel, invite the app first by typing /invite @iHatePosting in that channel.
Use Slack's own formatting
Slack formats message text with its own markup: *bold*, _italic_, ~strikethrough~, `code` in backticks, and a > at the start of a line for a quote (Slack's developer documentation, checked November 2026). Write these into the Slack override so other networks don't show the symbols.
Mentions stay quiet
iHatePosting posts with automatic mention linking turned off, so a caption cross-posted from another network never pings everyone with @channel or @here by accident.
Let threads carry the conversation
Replies to a Slack announcement usually land in a thread under it. iHatePosting reads the reactions and thread replies on each post, and the member count of each channel, so you can see which announcements people responded to.
Time team announcements for the working day
Schedule announcements for when most of the channel is online, which for a team is usually the start of its working day in its own time zone. Keep the key point in the first line so it still reads well in notifications and channel previews.
Schedule from ChatGPT or Claude
Connect iHatePosting to ChatGPT or Claude once, then ask in plain words: “Schedule this update to our #announcements Slack channel tomorrow at 9am.” The agent can check the draft against Slack's limits with validate_post, schedule it with create_post, and move it later with reschedule_post. The post appears on your calendar like any other, and you can edit or cancel it in the app. The ChatGPT and Claude pages under AI agents, and the guide to posting from an AI agent, walk through the setup.
Free for 90 days, no credit card needed. Everything is included during the trial: unlimited accounts, unlimited posts, every feature. See iHatePosting pricing for the single plan, and the character limits guide for every network's caps.
Related reading
- Schedule Discord posts covers community announcements by webhook.
- Schedule Telegram posts covers channel announcements.
- Connect iHatePosting to Zapier, Make or n8n triggers Slack posts from other tools.
Frequently asked questions
Can you schedule a message in Slack?
Yes. Write the message, click the arrow next to the send button (or tap and hold it on mobile) and choose a time. Slack sends it for you at that time.
Does the schedule message Slack option work on mobile?
Yes. In the Slack mobile app, tap and hold the paper-plane send icon and choose a time. Scheduled messages are under Drafts & sent, in the Scheduled tab.
Where do I find my scheduled messages in Slack?
Open Drafts & sent at the top of the sidebar and select the Scheduled tab. From there you can edit or delete a message before it goes out.
Can iHatePosting post to a private Slack channel?
Yes, once the app is in the channel. Type /invite @iHatePosting in the private channel, and iHatePosting can post there from then on.
Can I send one post to several Slack channels and social networks at once?
Yes. Each Slack channel you connect is its own account in iHatePosting, so you can pick several channels and any of your other networks for the same post.