The short version
Your messages are never dropped or lost. When a workflow would send a large volume of communications at once, Sense paces delivery — messages go out steadily over the following hours instead of all in the same moment. Everything you scheduled still gets sent; it just may not all leave at the exact same time.
Why Sense paces sends
When one workflow sends a very large volume all at once — for example, an activation with no conditions that pushes your full audience immediately — it can cause two problems:
- Your messages get blocked or filtered. Carriers and providers (mobile networks, email inboxes, WhatsApp, voice carriers) watch for sudden spikes. A huge burst from one sender can be flagged as spam, throttled, or blocked outright — which hurts your delivery and your sender reputation.
- It crowds out your other communications. You often have other active workflows and communication groups sending to other people at the same time — chatbot over SMS, email, and so on. If one large send consumes all the available capacity, those other communications can be delayed or blocked too.
This is exactly why we pace sends. The limit is shared across your whole account on purpose: it makes sure no single send can compromise everything else you have running. By spreading delivery out, Sense protects the deliverability of all your communications and keeps every channel moving — a deliberate safeguard, not a restriction.
How the limit is decided
Limits are set at two levels:
- By channel (carrier): SMS, Email, Voice, and WhatsApp each have their own hourly send limit, because each carrier and provider has different rules for what a healthy sending rate looks like.
- By the module within a channel: Within a single channel, different send methods have different limits. For example, standard Email and Chatbot over Email are paced separately, and SMS and SMS over Chatbot are paced separately — even though they share the same underlying channel.
Each of these limits is shared across all of your active workflows. So if several active workflows send SMS at the same time, they draw from the same hourly SMS budget rather than each getting a full allowance.
What you'll see in Sense
- When you activate a workflow: If a workflow will start sending to its full audience immediately (no conditions on the trigger or entry steps), you'll see a note telling you the relevant node is paced and at what hourly rate. You can still activate — this is only a heads-up.
- Inside an active workflow: While pacing is in effect, a banner shows which node is paced and its hourly rate.
- On the Workflows list page: A banner at the top of the page shows when any of your active workflows are being paced right now, and for which channels.
In all cases the message is the same: sending is happening at a steady rate, and the remaining messages are queued and will send automatically.
What happens to queued messages
Queued messages are held safely and sent automatically as capacity frees up over the following hours. Nothing is discarded and nothing needs to be re-triggered — you don't have to do anything.
Pacing respects your blackout windows
Pacing never overrides your blackout settings. If a queued message is due to send during a blackout window, Sense honors that window — depending on how your blackout is configured, the message either waits and sends once the window reopens (for example, the next day) or is skipped entirely. Pacing only controls how fast messages send within your allowed times; it never sends outside them.
Best practices for large-volume sends
Because the limit is shared and applies to your full audience when there are no conditions, the best way to get your communications out efficiently is to send to fewer people at a time:
- Batch your sends. For large audiences, split the send into smaller batches instead of sending to everyone at once. Batching consistently improves delivery and keeps messages flowing steadily rather than hitting the limit and queuing.
- Use trigger conditions. Add conditions to your trigger or entry steps so communications go out in a more conditional, targeted way — reaching the right segment sooner instead of your entire audience at the same moment.
- Stagger your workflows so they aren't all sending on the same channel at the same time.
Smaller, more targeted sends clear faster and tend to land better with carriers and inboxes.
FAQ
Are any of my messages being deleted? No. Every scheduled message is sent. Pacing only affects when messages go out, not whether they go out.
Why is my workflow sending slower than another? The hourly limit for each channel and module is shared across all your active workflows. If several workflows use the same channel at once, they share that capacity.
Do I need to do anything? No. Queued messages send automatically. Batching, adding conditions, or staggering workflows is optional and only needed if you want a specific group reached sooner.