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postoni

SSlack scheduler

Schedule Slack announcements

Use Postoni as a Slack message scheduler for the channels your team or community reads. Write the announcement once, pick a channel, and it posts on time. It is handy when a public launch on LinkedIn or X needs a matching heads-up inside Slack.

Schedule Slack posts freeSee pricing
  • 7-day free trial
  • No credit card
  • Unlimited posts
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Bloom Studio

@bloomstudio · now

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Our autumn collection lands Friday. Twelve new glazes, all made by hand in our tiny studio.

Scheduled · Tue 11:30 AM
Illustration of a scheduled Slack post in the Postoni composer

Everything you can publish to Slack

Pick the format in the composer. Postoni handles the upload and the timing.

  • Channel announcements
  • Image posts
  • Threaded replies

Built around how Slack actually works

  • Posts under your name and icon

    Messages show the name and picture of the connected account rather than a generic bot label, so announcements read like they came from you.

  • Joins public channels for you

    Pick any public channel and Postoni joins it before posting. You don't have to invite the app to each channel by hand.

  • Details go in the thread

    Add replies to your announcement and they post as a thread under it. The main message stays short and scannable.

How to schedule a Slack post

Four steps, about two minutes the first time. After that it's write, tweak, schedule.

  1. 1

    Install Postoni in your workspace

    Connect Slack and approve the app for your workspace. Some workspaces need an admin to approve new apps first.

  2. 2

    Write the update

    Draft it in the composer. Slack formatting like bold, links and lists comes through in the message.

  3. 3

    Choose the channel

    Pick a channel from the list Postoni loads. For a private channel, invite the Postoni app to it first so it can post.

  4. 4

    Schedule and relax

    Set the date and time and Postoni posts it. Move it on the calendar if plans change.

Slack scheduling FAQ

Free Slack tools

Slack character counter

Check a draft against the 40,000-character limit before you post.

Character counter for every network

Paste one draft and see which networks it fits.

Does Postoni publish automatically to Slack?

Yes. After you install the app, scheduled messages post to the channel you picked at the time you set, with no one needing to be online.

What is the Slack character limit?

Slack messages can be 40,000 characters, but Postoni posts your text in a formatted section and Slack limits those to 3,000 characters. For anything longer, split it into a short post and threaded replies.

Can Postoni post to private channels or send DMs?

It can post to private channels once you invite the app to them. It doesn't send direct messages to people.

Why schedule Slack posts in a social media tool?

Because launches rarely happen in one place. Keeping the Slack heads-up in the same calendar as your public posts means your team and your audience hear about it at the same time.

Pairs well with Slack

Most people post the same idea to a few networks. These are the ones that usually go with Slack.

See all channels

Ready to put Slack on autopilot?

Connect Slack, write your first post and schedule it in two minutes. Free for 7 days, no card.

Start free for 7 days
  • Unlimited posts on every plan
  • Cancel anytime
  • Open-source core