NetworksSlack

Slack APIthrough Siar.

Q: Can I schedule Slack posts?

Yes. Set postDate in the future and a status of SCHEDULED. Siar publishes at that time and sends a post.published webhook when the post reaches a final state.

Messages to Slack channels, with files and an optional custom bot name and icon.

Quickstart Slack errors

At a glance

Account needed: A Slack workspace where the Siar app is installed. Each post names the channel.

Connection	OAuth 2.0 in the browser
Channel	Required: pick a channel after connecting
Post types	post
Text length	40,000 characters
Comment length	40,000 characters
Media per post	Up to 10

Media rules

Kind	Formats	Max size	Duration	Other
Image	any type	1 GB	n/a	None
Video	any type	1 GB	Up to 24 h	None
Document	any type	1 GB	n/a	None

What Siar can do on Slack

Comments and replies	Yes
First comment	Yes
Edit a published post	Yes
Delete a published post	Yes
Edit a comment	No
Delete a comment	Yes
Import comments	Yes
Post analytics	Yes
Account analytics	No
Post history import	No
Direct messages	No

Siar can create comments and replies up to 40,000 characters, and import the comments people leave on your posts.

Publish a post

Put Slack's payload under data.SLACK and list SLACK in socialAccountTypes. Add other networks to the same request to post to all of them at once.

curl -X POST "https://api.siaran.my/api/v1/post" \
  -H "x-api-key: $SIAR_API_KEY" \
  -H "content-type: application/json" \
  -d '{
    "teamId": "TEAM_ID",
    "title": "Slack post",
    "postDate": "2026-11-02T09:00:00.000Z",
    "status": "SCHEDULED",
    "socialAccountTypes": [
      "SLACK"
    ],
    "data": {
      "SLACK": {
        "channelId": "CHANNEL_ID"
      }
    }
  }'

Slack fields

channelId string required
text string nullable
uploadIds string[] nullable
username string nullable
avatarUrl string nullable

Daily caps

Per connected account, per UTC day	Free	Pro	Business
Posts	10	100	200
Comments	3	100	200

See pricing for monthly quotas. Enterprise uses the Business caps unless agreed otherwise.

Connecting a Slack account

Siar sends the user to the network's consent page and stores the tokens it gets back, refreshing them before they expire. Use POST /social-account/connect from your own UI, or send your customer a hosted link from POST /social-account/create-portal-link; see connecting accounts.

Permissions requested

Siar requests only these scopes at connect time:

chat:write
chat:write.public
chat:write.customize
channels:read
groups:read
channels:history
groups:history
files:write
files:read
reactions:write
users:read

Slack-specific operations

These exist for Slack only and live under /misc/slack.

Operation	Endpoint
Edit an existing Slack message	PATCH `/misc/slack/message`
Delete a Slack message	DELETE `/misc/slack/message`

When Slack says no

Siar relays Slack's error code and message verbatim on the post, next to a status you can act on. The Slack error reference covers 10 common cases with what each one means and the fix. Open the Slack error reference.

Slack API questions

What can I post to Slack through the API?

post. Messages to Slack channels, with files and an optional custom bot name and icon.

How many Slack posts can I publish per day?

Per connected account and UTC day: 10 on Free, 100 on Pro, 200 on Business. The caps keep the account within what Slack tolerates.

Can I schedule Slack posts?

Yes. Set postDate in the future and a status of SCHEDULED. Siar publishes at that time and sends a post.published webhook when the post reaches a final state.

How do I connect a Slack account?

A Slack workspace where the Siar app is installed. Each post names the channel. Siar sends the user to the network's consent page and stores the tokens it gets back, refreshing them before they expire.

What do I do when Slack rejects a post?

The post carries Slack's own code and message. The Slack error reference explains 10 common rejections and how to fix them.

Other platforms

TikTok · YouTube · Instagram · Facebook · X (Twitter) · Threads · LinkedIn · Pinterest · Reddit · Mastodon · Discord · Bluesky · Google Business Profile · Snapchat

Your first post isone request away.

The Free plan includes 20 posts and 200 uploads a month across 3 teams. No card needed.

Start free Read the quickstart