How it works
There are two rules. Each has its own on/off switch, and you can use either, both, or neither.
What counts, and what is limited: proactive messages sent by a journey step.
That is WhatsApp templates, SMS and email.
What never counts and is never limited:
- The agent’s replies inside a conversation.
- Messages your team sends from the inbox.
- Instagram and Messenger messages, which only go out inside a conversation the person started.
- Anything in your test environment, and WhatsApp messages to your organization’s test numbers.
- Each channel is counted on its own. An email never uses up someone’s WhatsApp allowance.
- The window is rolling, not a calendar day. “1 every day” means 24 hours after the last message, not “once today”.
- First come, first served. Every message counts toward the limit, whichever initiative sent it, and the first one to reach the person takes the slot. There is no priority between initiatives. Use Exceptions for the ones that must always go out.
- A change applies at once, to everyone. Raise, lower or turn off a rule and the next message is checked against the new setting.
Set it up
1
Review your exceptions first
Open Settings › Smart Sending and look at Exceptions. Add every
initiative whose messages people need, like document requests, payment links,
renewals or order updates. Those always send.
2
Turn on the message limit
Flip Message limit. A dialog asks how many messages and how often (for
example “At most 1 message per person every day”) and on which channels.
WhatsApp is ticked by default; tick SMS or Email only if you want them limited
too. The dialog also lists any initiative that would lose messages, each with
a one-click Add to exceptions. Nothing changes until you click Turn on.
3
Optionally, turn on the cooldown
Flip Cooldown between initiatives and pick how long: 7, 14, 30, 60 or 90
days.
4
Check an initiative
Each initiative’s page says, under its details, whether it Always sends or
Follows Smart Sending, and which rule applies.
The message limit
Pick 1, 2 or 3 messages per person, every day, every 2 days, or every week, on the channels you tick. The card then shows the limit with a checkbox per channel, so you can extend it to another channel or narrow it later. To give each channel its own numbers, open Customize per channel. There you can set up to 10 messages in a window of up to 7 days (168 hours) per channel. A send held for approval as a draft is checked when it is delivered, after someone approves it, not when the draft is created.The cooldown
The cooldown is the longer rule: “don’t contact this person from another campaign for 30 days”. It is checked when someone is added, so a person inside their cooldown is never added in the first place, rather than added and then stopped halfway. It counts messages on any channel from other initiatives. An initiative’s own messages never block it. These are always let through:- Someone who messaged you first, or commented on your post.
- A conversation being handed from one initiative to another.
- An initiative in Exceptions.
enrollment.rejected with reason: "cooldown". When you start a journey for
several people at once, the confirmation says how many were skipped because of the
cooldown.
Exceptions
Every initiative follows the limit and the cooldown, unless it is an exception. An exception always sends: its messages go out even over the limit, and it ignores the cooldown.- Add them in Settings › Smart Sending › Exceptions with Add initiative, which opens a searchable list showing each initiative’s status. You can tick several and add them in one go.
- Or on the initiative itself: turn on Always send under Smart Sending in its Agent step. On a campaign, it is under Options › Smart Sending.
- Transactional messages start as exceptions, since a notification has to go out. You can change that with Always send, under Options on the Transactional’s page.
What happens to a skipped message
A message over the limit is skipped, not sent later, and not resent.- In the journey, the send step takes its Capped, not sent exit instead of Sent. Leave that exit unconnected and the person’s run ends there. Connect it to do something else: wait a day and try again, try another channel, or end on purpose.
- In Executions, the run is labelled Skipped rather than Completed. Hovering the label names the rule, for example “Over the limit: 1 message every day on WhatsApp”. The Skipped by Smart Sending filter shows only those runs.
- On the person’s timeline, the step reads Skipped by Smart Sending.
- In totals, the initiative’s overview counts runs skipped by Smart Sending and leaves them out of Completed, since they were stopped, not finished. Settings › Smart Sending shows how many messages were skipped in the last 14 days. Sent counts in analytics only include messages that went out.
Recommended setups
Coming from Klaviyo?
If you used Klaviyo’s Smart Sending, most of it maps directly. The differences:Set it up with Claude
Everything on the settings page is also available through Boom’s MCP tools, for admins of your organization:Good to know
- Nothing is limited until you turn a rule on. Your organization still records every send, so the day you turn a limit on it already knows who was messaged recently.
- If Smart Sending can’t check, the message goes out. An outage on our side never silently stops your messages.
- To turn a rule off, flip its switch. It stops immediately.
- Holding a skipped message and sending it once the window clears is coming.