> For the complete documentation index, see [llms.txt](https://docs.feedotter.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.feedotter.com/automations/scheduling/how-feedotter-detects-new-content.md).
# How Feedotter Detects New Content
Feedotter determines whether content is new by evaluating the published date of articles in your feed and comparing that date to your automation's last send date.
Understanding this process is important because it directly affects which articles are included in your automated newsletters.
### Published Date (pubDate)
Most RSS feeds include a published date for each article, commonly referred to as the **pubDate**.
Feedotter uses this value to determine when content was published and whether it should be considered new.
***
### Last Send Date
Each automation keeps track of its most recent successful send.
When the automation runs, Feedotter compares the published date of each article in the feed against the automation's last send date. This can be found on the Automation Details page.
**Articles published after the last send date are considered new and may be included in the next email.**
***
### First Send Behavior
When an automation sends for the **first time**, there is no previous send history to compare against.
As a result, Feedotter considers **all qualifying content in the feed to be new** and **includes up to the maximum number of posts configured for the automation.**
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### Previously Sent Posts Filter
This filter helps prevent duplicate content from appearing in future emails. You can find this in your automation settings.
When checked, Feedotter logs each article URL and prevents it from being sent again—even if the publish date changes. With multiple feeds, URLs from all feeds are tracked and filtered.
The Previously Sent Posts Filter:
* Maintains a record of URLs sent by the current automation
* Prevents previously emailed articles from being reused
* Helps avoid duplicate sends when content is edited or republished
{% hint style="info" %}
**Note:** The Previously Sent Posts Filter only functions when the Published Date Filter is enabled.
{% endhint %}
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