By default, MailerLite triggers an RSS campaign only when your RSS feed has new posts.
If the campaign was sent although no new posts were published, it might be that your campaign was canceled from the Outbox and rescheduled. Once a campaign is canceled, our system can’t compare which campaigns have been sent already, so the first “new” RSS campaign sends all recent posts.
Furthermore, a campaign can be triggered if an existing RSS feed URL is changed/updated. MailerLite recognizes the content in your feed by comparing the <guid> tag. This tag is usually an identification that a post is new and so an RSS campaign will be sent.
How RSS campaigns work
When you first create an RSS campaign, you’ll see that the content will be immediately filled up with the most recent posts in the feed.
However, this specific content is only shown as an example of what the RSS campaign will look like in future sendings. The feed is checked and processed five minutes before the campaign is actually sent.
You can choose whether you want to show only new posts or existing posts in each campaign. This is helpful if you don’t want to flood your subscribers with older posts they have already seen. Every post will only be sent once. However, an RSS campaign will not send at all if there are no new posts.