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Starting a Run

Sending a campaign means starting one of its runs. You can start a run immediately or schedule it for a future date and time. This page covers the Start Run flow, the warming-up window, scheduling, and what happens while messages send.

Prerequisites​

Before a run can be started:

  • You need a run in a Ready to Run status. Create one from the campaign if you don't have one yet.
  • For SMS under the Sender Selection strategy, the campaign's chosen sender must still be available on Twilio and in the Outreach available sender list. This is checked when you start the run, not when you create it — see Unavailable senders.

You are not blocked by another run. Any number of runs can send in parallel, including several runs of the same campaign, with no per-campaign or per-channel limit. See Concurrency and Throughput.

The Start Run Page​

Starting a run opens the Start Run page (breadcrumb: Campaign → Run → Start Run), titled Send Messages in [run name], with a Start button. It has three sections.

1. Preview Your Template​

A preview of exactly what will be sent. For SMS under Sender Selection, the Sender is shown. For email, the preview includes the subject, sender details, body, and any attachments.

2. When Should Messages Be Sent?​

Choose when the run sends:

OptionBehaviour
NowStart sending immediately. The run first enters a 5-minute warming-up window.
LaterPick a date and time to schedule the run. You can cancel or reschedule it any time before it starts.

When Later is selected, choose an At date/time and a Timezone:

  • The earliest schedulable time is at least 15 minutes from now, in 15-minute intervals. For example, at 13:02 the earliest available slot is 13:30.
  • The run respects the selected timezone when it starts.

3. Accept Terms and Conditions​

You must accept the run disclaimer before starting. It confirms you have obtained all required consents and permissions and will comply with applicable spam, privacy, and telecommunications laws. See Terms and Conditions for the full text.

When everything is set, click Start.

Warming Up​

Runs started Now enter a Warming Up state for 5 minutes before any messages send. This gives you a brief window to catch problems — a run can be cancelled during warming up, which returns it to Ready to Run and sends nothing, so a mistake caught early costs nothing. Once the window elapses, the run moves to In Progress and messages begin dispatching.

Scheduled runs do not warm up

A run scheduled with Later does not have a warming-up window. The Scheduled state is itself the cancellation window, so when the scheduled time is reached the run goes straight to sending.

Scheduled Runs (Start Later)​

When you schedule a run for later:

  1. The run moves to Scheduled. Its messages already exist — they were created when the run was created — so nothing further is needed for it to send.
  2. You can update the scheduled start time or cancel the run while it is scheduled. Cancelling reverts it to Ready to Run rather than deleting it, so the prepared run is kept and can be started manually later.
  3. When the scheduled date and time is reached, the run starts automatically — no manual action is needed.

What Happens During a Run​

SMS​

  1. Messages are queued and sent in batches.
  2. Each message moves through status transitions: Queued → Sending → Sent → Delivered (or Failed / Opted Out). Sent means the message was handed off to the recipient's carrier with no confirmation back yet; it only becomes Delivered once a delivery confirmation is returned. See Campaign and Message Statuses.
  3. Message statuses update in near real-time as delivery progresses.
  4. Messages in the "Sent" state for more than 10 minutes without a delivery confirmation are automatically updated to Assumed Delivered (not all carriers report final delivery).
  5. Messages in the "Sending" state for more than 10 minutes are updated to Failed with a reason of "Timed Out".

Email​

  1. Messages are queued and sent in batches.
  2. Each message moves through status transitions: Queued → Sending → Delivered (or Failed / Opted Out / Retrying).
  3. Message statuses update in near real-time as delivery progresses.
  4. Messages that are deferred by the receiving server enter a Retrying state until delivery succeeds or permanently fails.

Throughput and Queuing​

Even after a run starts, individual messages may be queued if the available sending capacity is already fully used. When this happens the run still moves to In Progress and its messages wait their turn — sending is pending, not failed. When starting a run you can see approximately how many messages are ahead of yours and an estimated wait time. High-priority messages in a starting run are dispatched ahead of normal-priority messages in other active runs — see Message Priorities. How that capacity is shared between runs is covered in Concurrency and Throughput.

Failure Handling​

  • Messages that fail due to pre-send errors (errors before the message reaches the delivery provider) are automatically retried up to 3 times before being marked as Failed.
  • Messages that fail due to post-send errors (undeliverable, bounced) are marked as Failed with a specific failure reason.
  • SMS messages sent to recipients who have opted out are automatically detected and marked as Opted Out.

Unavailable Senders​

Under Sender Selection, the chosen sender is not checked when a run is created — you can always prepare a run. It is checked twice around starting instead:

  1. When you click Start. The sender is validated immediately. If it is unavailable, an error is shown there and then, the run is left unstarted in Ready to Run, and no email is sent — you can fix the problem while you are still in context.
  2. When sending is due to begin. The sender is checked again, at the end of the warming-up window for a run started now, or at the scheduled time for a run started later or created automatically from a Repeat schedule. If it has been removed in the meantime, the run moves to Setup Failed and an email is sent to the campaign owner.

The second check catches a sender that is removed from Twilio or de-listed by an Org Admin after start is clicked, and means an automatic run on a broken schedule never fails silently.

Stopping and Cancelling​

StateActionEffect
In ProgressStopOnly queued (unsent) messages are removed from the sending queue. Messages already sending or sent are unaffected.
ScheduledCancelThe run reverts to Ready to Run and can be started manually later. It is not deleted.
Warming UpCancelThe run reverts to Ready to Run and no messages are sent.
warning

Stopping a run that is In Progress does not recall messages that have already been sent. Only unsent (queued) messages are cancelled.

Next Steps​