Send and delivery speed of email campaigns is affected by a number of internal and external factors. Pro Marketer Accounts have considerably faster send speeds, which is required for delivering large volumes of messages.
Send speed of campaigns from all account types is affected by the following factors:
- Total number of subscribers receiving the campaign
- Number of images embedded in the campaign (not linked)
- Number of attachments to the campaign (if any)
- Total campaign size (in bytes)
Send speed of campaigns sent from standard accounts on the cloud hosting platform is affected by the following factors:
- Time of day the campaign is sent
- Busyness of other clients using the cloud platform
- Total number of campaigns being sent from the same account simultaneously
- Active campaigns being sent by other sub-account users
Once messages have been sent, the time they takes to appear in subscriber inboxes is determined by Subscribers’ email hosting providers (their technical configuration and efficiency of operation).
Processing speed vs delivery speed
The number of processed messages, and the processing speed which are stated on the Active tab of the Campaigns page reflect the generation of messages and their dispatch to phpList’s internal mail queues. Usually messages added to the mail queue are sent instantly. In cases where delivery is delayed however, the processing speed and sent status does not reflect the delivery speed or that the messages were received.
Rarely, phpList’s internal mail queue may try to send the same message several times after unsuccessful attempts. In such cases, delivery will take longer. and the number of processed messages may be greater than the total number of campaign recipients. This is because individual messages will, in such cases, have been processed multiple times. Messages are never delivered twice to a single recipient of a single campaign, however, in any circumstances.
For Standard and phpList Plus accounts
We process mail queued for delivery every 2-5 minutes, and send in batches of 1,000 messages.
phpList uses domain throttling to protect deliverability and the reputation of our network. This ensures not too many mails to go a single provider in a given time frame. If you have many subscribers on the same domain (e.g. hotmail.com) it may delay your campaign a little, as recipient mail servers often have restrictions on how may messages they can receive in a given time frame.
After a few months of responsible usage of your phpList account, the sizes of the batches of messages used by your account automatically increases, which means your campaigns will be delivered more quickly.
For Pro Marketer Accounts
No batch processing is used; campaigns are sent as fast as the server is capable, within the limits set by domain throttles in order to ensure maximum deliverability.