Linking Slack as a source

The Slack connector syncs channels, users, and messages from your Slack workspace into PostHog's data warehouse.

Available tables

Adding a data source

1. In PostHog, go to the Data pipeline page and select the Sources tab.
2. Click + New source and select Slack by clicking the Link button.
3. Click Connect and authorize PostHog to access your Slack workspace.
4. Optional: Add a prefix to your table names.
5. Select the tables you want to sync. Each channel appears as its own table you can enable or disable individually.
6. Click Import.

PostHog requests the following OAuth scopes from your Slack workspace:

Setting up the webhook for message syncing

Because channel message tables rely entirely on webhooks, you need to create a Slack app that forwards message events to PostHog. Without this step, your channel tables stay empty.

1. Go to your Slack source in the data pipeline sources tab and click the Webhook tab.
2. Copy the webhook URL shown – you'll paste it into the manifest below.
3. Open Slack apps and click From a manifest.
4. Pick your workspace and click Next.
5. Paste the following manifest into the editor, replacing {webhook_url} with the URL you copied in step 2:

{
  "display_information": {
    "name": "PostHog data warehouse",
    "description": "Sync Slack messages and channels to PostHog data warehouse"
  },
  "oauth_config": {
    "scopes": {
      "user": ["channels:history", "groups:history"]
    }
  },
  "settings": {
    "event_subscriptions": {
      "request_url": "{webhook_url}",
      "user_events": ["message.channels", "message.groups"]
    },
    "org_deploy_enabled": false,
    "socket_mode_enabled": false,
    "token_rotation_enabled": false
  }
}

6. Click Next, then Create.
7. In the left sidebar, click Install App, then Install to Workspace, and authorize.
8. Go to Basic Information > App Credentials, copy the Signing secret.
9. Back in PostHog, paste the signing secret into the Signing secret field on the Webhook tab and save.

PostHog uses the signing secret to verify that incoming events actually came from Slack. Once the webhook is active, new messages in your enabled channels start appearing in their tables.

Common issues

Bot not installed

Events won't be sent to PostHog if the Slack app hasn't been installed to your workspace. Even after creating the app and configuring the webhook, you still need to explicitly install it.

To verify:

1. Go to your Slack app settings.
2. Select your PostHog data warehouse app.
3. Click Settings > Install App in the left sidebar.
4. Confirm the app shows as installed. If not, click Install to Workspace and authorize it.

See Slack's Installing with OAuth documentation for more details.

Webhook shows "Doesn't respond"

When you enable Event Subscriptions, Slack sends a verification challenge to your webhook URL. If this initial handshake fails, the status stays stuck on Doesn't respond.

To fix this:

1. Go to your Slack app settings and select your app.
2. Click Features > Event Subscriptions in the left sidebar.
3. Re-enter or re-paste the Request URL from PostHog's webhook tab.
4. Slack should show a green Verified checkmark.

If verification keeps failing:

• Confirm the webhook URL is correct (copy it fresh from PostHog).
• Check that your PostHog source is still active and hasn't been deleted.
• Wait a few seconds and try again – transient network issues can cause failures.

See Slack's Events API documentation for more on how URL verification works.

Configuration