How Letterhead detects duplicates in your RSS feed

When Letterhead pulls content from your RSS feeds, it automatically filters out duplicate items so your Curations library stays clean. Knowing how duplicates are identified helps you structure feeds to avoid accidental repeats.

How duplicates are identified

For each incoming item, Letterhead compares a few key attributes:

• Original URL — the item’s direct link. If that URL has already been processed, the item is flagged as a duplicate. This is the primary signal.
• Channel — the check applies within the channel the feed belongs to.
• Feed identity — items are tracked back to the feed they came from, so Letterhead knows each item’s origin.
• Item type — items pulled automatically from RSS are tracked separately from manually curated ones.

Together these ensure identical items aren’t duplicated within a single feed or channel.

Best practices to avoid duplicate issues

• Use unique, consistent URLs — detection keys on the URL, so the same content published under different URLs is treated as distinct. Give each piece of content one canonical URL.
• Avoid redirects in feed URLs — URLs that redirect to another destination may be treated as unique even when they point to the same content. Use direct URLs in your feed.
• Watch multi-source feeds — if you pull from several feeds, make sure the same content isn’t arriving under different feeds.
• Standardize your metadata — consistent URL and metadata structure helps the system recognize repeats.

If a feed has gotten tangled and you want Letterhead to reprocess it from scratch, you can reset the feed — just note that resetting re-curates every item, including ones already used.