Submission speed is something to consider when sending to an exceptionally to high volume, or during a ramp-up. Sending a campaign without adapting the speed can lead to the failure of the campaign or to two undesirable effects:
- for deliverability: a campaign with an unusually high amount of recipients would generate more bounces or spam complaints during a short period of time and can lead to temporary rejections by the receivers. Furthermore, reputation systems takes into account the variations of volume: a sudden peak can have negative consequences.
- for the landing website: the campaign can generate too much traffic on the website, saturate it and make it unreachable for new visitors.
If in doubt, get in touch with your Splio contact to discuss the matter!
What is the submission speed?
The submission speed is a maximum number of emails sent during a specific time. It is, in fact, throttling. So if we set a speed of 5,000 emails per hour, the campaign will send a batch of a few emails at the beginning of the sending, another similar batch again after a short pause, etc.
The bellow chart shows the partial smoothing resulting from the throttling, in green, over two hours, for a maximum speed of 20,000 emails per hour. The counter example, which doesn't represent this feature's behavior, is shown in red.
The sending speed is the maximum number of emails to be sent over an hour. The volume of emails sent in each batch and the frequency of those batches also depends on the platform capacity at the time. Therefore, this feature does not guarantee the sending of a minimum volume per hour, nor a perfect smoothing of the sending (hence the little crests in the above chart).
Set the submission speed of a action's campaign
Go to the settings of the campaign's action and go to the sub-menu "submission speed".
Adapting speed based on volumes variations
The submission speed must be adapted when the target population is unusually high, the targeted speed being roughly what the usual speed is, or even slow it down a bit to ensure messages are delivered. ISPs indeed can expect a certain volume but become suspicious when there are notably more messages than usually. Slowing the pace down gives them the opportunity to analyze the content and see that the higher volume isn't an attempt to sneak suspicious traffic in.
For example, if the usual target is around 200,000 but that there's a campaign on 400,000 coming, the user should setup a speed of 50,000 emails per hour to not send faster than usual.
Although there are many other variables in the equation (the number of outbound IP addressed to be used, the receiving ISPs, the queues, the per-ISP sending rules ...), the above example is a good rule of thumb.
Adapting the speed for the landing website
Here it's necessary to assess the website's capacity with the responsible administrators. They indeed should know how many visitors the website can handle simultaneously, and the sending speed would be chosen based the usual click-through rate.
In this example, the administrator determined that the website can not handle more than 40,000 visits per hour, and the usual click-through rate is 15% on email campaigns.
In this context, we can calculate that:
- if a campaign is sent to 200,000 recipients (with no speed limit), the campaign should generate around 30,000 visits on the website (click-through rate * targeted recipients / 100) : this speed shouldn't induce problems for the website.
- if a campaign is sent to 400,000 recipients (with no speed limit), the campaign should generate around 60,000 visits on the website in the hour following the launch of the campaign, and in the given context the website might be overloaded. To prevent this from happening, we can setup a 40,000 per hour speed limit and stay within the website capacity.
Note: the outbound speed throttling feature is also available for SMS campaigns.