If you’re running a newsletter from multiple content sources, you need some form of RSS feed aggregation - a way to combine content from different feeds into a single newsletter delivery. Several approaches exist, and they’re not equivalent. This guide compares them so you can choose the one that fits your situation.
The short answer: use a simple feed merger when every subscriber should receive the same combined content. Use separate campaigns when each feed represents a genuinely separate newsletter. Use preference-matched multi-feed automation when subscribers have overlapping interests and should receive different combinations of content in one email.
Before choosing a tool, list the feeds, audiences, item limits and duplicate rules you need. The multi-feed newsletter planning guide provides that platform-neutral checklist.
RSS email aggregation options compared
| Approach | One email | Subscriber-level relevance | Ongoing effort | Best fit |
|---|---|---|---|---|
| Merge feeds into one URL | Yes | No | Low | One broadly similar audience |
| Separate campaign per feed | No | Segment-level | Medium to high | Distinct newsletter products |
| Preference-matched multi-feed campaign | Yes | Yes | Low after setup | Overlapping audience interests |
| Custom aggregation | Configurable | Configurable | High | Bespoke requirements and engineering capacity |
Approach 1: Feed merge services
Tools like RSS.app, FetchRSS, and similar services combine multiple RSS feed URLs into a single merged feed. You give them several feed URLs; they return one combined URL that you point your Mailchimp campaign at.
Mailchimp also documents native options for adding multiple feeds with feed merge tags or using a combined feed in its RSS automation guidance.
How it works: items from all source feeds are combined into one feed, typically ordered by publication date. The merged feed updates automatically as source feeds update.
Best for: organisations with a reasonably homogenous audience who want to include content from multiple sources without building anything complex. Simple to set up. No personalisation capability.
Limitations: everyone gets the same merged content. No subscriber-level filtering. High-frequency sources dominate the output unless you configure per-source limits.
Approach 2: Multiple separate campaigns
Create a separate Mailchimp RSS campaign for each content type, each connected to its own feed. Send each campaign to the relevant subscriber segment.
How it works: you maintain multiple campaigns - one per content vertical or audience type. Each runs independently, connected to its own feed.
Best for: organisations where content types are truly separate products and subscribers clearly belong to one or the other.
Limitations: operational overhead scales with the number of campaigns. Each campaign requires separate setup, monitoring, and maintenance. Subscribers who are interested in multiple content types receive multiple separate emails rather than one combined newsletter.
Approach 3: Multi-feed RSS with subscriber preference matching
A platform like FlipRSS connects multiple feeds, applies subscriber preference matching, and delivers personalised content to each subscriber segment via a single Mailchimp campaign.
How it works: multiple feeds are connected and labelled by content category. Subscriber groups in Mailchimp are mapped to the relevant feeds. One campaign produces different content for each subscriber based on their group membership.
Best for: organisations with diverse audiences and multiple content streams who want the operational simplicity of one campaign with the subscriber experience of personalised content. Publishers, universities, associations, non-profits.
Limitations: requires initial setup of feed connections and subscriber group mapping. More moving parts than a simple feed merge, though the ongoing operation is no more complex.
Approach 4: Custom aggregation
Build a custom solution - via server-side scripts, Zapier workflows, or a bespoke platform - that aggregates, filters, and delivers feed content according to your specific requirements.
Best for: organisations with very specific requirements that off-the-shelf tools don’t meet, or where the newsletter is a core product rather than a communication channel.
Limitations: development and maintenance overhead. Usually only worth it at significant scale or with a very specific set of requirements.
See how preference-matched multi-feed delivery works with Mailchimp.
How to choose
The right approach depends on three variables: audience homogeneity, content diversity, and available resource.
If your audience has broadly similar interests: a feed merge service is probably sufficient. Quick to set up, low maintenance.
If your audience has distinct segments with different content needs: multi-feed with preference matching produces a significantly better subscriber experience and is worth the setup investment.
If your content streams are genuinely separate products with separate audiences: multiple campaigns make sense, despite the overhead.
The mistake to avoid is using a simple feed merge for a diverse audience because it’s easier to set up. The operational simplicity produces the subscriber experience problems of an undifferentiated newsletter - everyone getting everything regardless of interest.
For publishers running newsletters to loyal but diverse readerships, the model worth building toward is automated newsletters that feel hand-curated - because the content is matched to reader interest.
Questions to ask before selecting an aggregator
- Should every subscriber receive every source feed?
- Can one subscriber belong to several interest groups?
- What happens when two feeds contain the same article?
- Can you limit items independently for each source?
- How are missing images and inconsistent excerpts handled?
- Can the team run a representative test before enabling automation?
- Who monitors failed feeds and changes to source URLs?
If the answer to the first question is yes, a merged feed may be enough. If subscribers need different combinations, choose an architecture that retains feed identity and applies preference rules rather than flattening everything into one stream.
How can FlipRSS help you?
FlipRSS saves content creators and publishers time by fully automating email newsletters whilst delivering content personalised to individual subscriber preferences.
FlipRSS integrates with Mailchimp to automate multiple RSS feeds in email newsletters. Subscribers can select the subjects they want, and FlipRSS applies those preferences when assembling each send. The Auburn University case study provides one measured example; results vary according to audience, content and campaign design.
Once set up, newsletters are created, customised and scheduled automatically.
What sets us apart?
We’re a small team. Small enough to really care. We care about the quality of the product we produce, we care about the experience of every customer we have the privilege of working with, and we care about our impact. We’re here to do a great job of supporting, delighting and connecting you and your subscribers.