Campaign send speed: explained

You prepared a campaign – wrote content, created template, selected the desired lists you want to send this campaign out – and lastly you clicked “Place campaign in queue for sending”. But, when this campaign will arrive at your subscribers’ mailboxes? Sending time and speed depends on several factors.

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 take to appear in subscriber inboxes is determined by Subscribers’ email hosting providers (their technical configuration and efficiency of operation).

For Standard and phpList Plus accounts

phpList processes mails 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. it may delay your campaign a little, as recipient mail servers often have restrictions on how many 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.

Pro Marketer Accounts (VPS)

For VPS 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. Interested in a VPS account for better deliverability results? Drop us an email to

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