Receive real-time notifications in your Slack workspace when important events happen in your MailBeast campaigns – lead replies, campaign completions, bounce spikes, and more.
A MailBeast account (any paid plan)
A Slack workspace where you have permission to add apps
Owner or Admin role in your MailBeast organization
In MailBeast, click Integrations in the left sidebar
Click on the Slack card
Open Slack Incoming Webhooks in a new tab
Click Add to Slack
Choose the Slack channel where you want to receive notifications (e.g. #sales-alerts) or create a new one
Click Add Incoming WebHooks integration
Copy the Webhook URL – it looks like https://hooks.slack.com/services/T.../B.../...
Security note: Your webhook URL contains a secret. Do not share it publicly or commit it to version control.
Go back to the MailBeast Slack integration page
Paste the Webhook URL into the Webhook URL field
Click Connect Slack
Once connected, you will see a green Active badge and the notification settings panel will appear.
After connecting, you can choose exactly which events trigger Slack notifications. Events are grouped into three categories:
Event | Description | Default |
|---|---|---|
New lead reply | A lead responded to your campaign email | On |
Lead status changed | A lead's status was updated (by AI classification, manually, or by system) | Off |
Auto-reply received | An out-of-office or auto-response was detected | Off |
Event | Description | Default |
|---|---|---|
Campaign started | A campaign began sending emails | Off |
Campaign completed | A campaign finished sending all emails | On |
Campaign auto-paused | A campaign was automatically paused (e.g. high bounce rate) | On |
Campaign resumed | A paused campaign was resumed | Off |
Event | Description | Default |
|---|---|---|
Account disconnected | An SMTP email account lost connection | On |
Bounce rate spike | An unusual increase in bounce rate was detected | Off |
Lead unsubscribed | A lead clicked the unsubscribe link | Off |
A/B winner selected | An A/B test variant was automatically chosen as the winner | Off |
Toggle each event on or off based on your needs, then click Save Changes.
Each notification includes relevant context so you can act quickly:
Lead reply: Shows the sender name, campaign, message preview, and a link to the thread in Inbox Hub
Campaign completed: Shows delivery metrics (emails delivered / total sent)
Bounce spike: Color-coded by severity – red for critical, orange for warning
A/B winner: Shows the winning variant and the metric it won on
All messages include a direct link back to the relevant page in MailBeast.
Enable/Disable: Use the toggle switch to temporarily pause notifications without removing the webhook
Delete: Click the delete button and confirm to remove the integration entirely
Change webhook URL: To switch to a different Slack channel or rotate the webhook, delete the current integration and set up a new one with the new URL
Issue | Solution |
|---|---|
Not receiving notifications | Check that the integration is enabled (green Active badge) and that the specific event toggles are turned on |
Invalid webhook URL error | Make sure the URL starts with |
Notifications going to wrong channel | Delete the current integration, create a new webhook in Slack for the correct channel, and set it up again in MailBeast |
Only high-signal events are sent to Slack (11 event types). High-volume events like individual email opens/clicks are not sent to Slack to avoid flooding your channel – these will be available via the Webhooks integration (coming soon).
Rate limit: 1 message per second with burst up to 3, matching Slack's own rate limits.
