How to Create a Custom RSS Feed for Mailchimp in WordPress

Creating a custom RSS feed for Mailchimp in WordPress lets your newsletter run from its own dedicated URL with settings built specifically for email — right image size, right content length, UTM parameters already in place. Here’s how to set one up.

Why a Dedicated Mailchimp Feed Makes Sense

WordPress gives you one RSS feed by default at yourdomain.com/feed. If you connect that directly to Mailchimp and also use it for Feedly, Google News, or any other platform, you’re stuck with one set of settings for all of them.

The problem is that what works for email doesn’t always work elsewhere. Mailchimp RSS campaigns render best with a landscape image at around 600px wide. A feed reader subscriber might prefer full post content. Google News has its own requirements around post counts and content format. When one feed has to serve all of those, you end up compromising on all of them.

A custom feed for Mailchimp sits at its own URL — something like yourdomain.com/feed-mailchimp — and has its own independent settings. Image size, content length, custom HTML, UTM parameters: all configured specifically for your newsletter without touching your default feed or any other feed you run.

What You Need

A custom RSS feed URL is a Pro feature in RSS Chimp. The free version works with your default WordPress feed. Pro adds the Custom Feeds tab where you can create as many additional feeds as you need, each with a custom slug and independent settings.

If you’re on the free version and want to follow along, you can start a 14-day Pro trial without a credit card.

Setting Up the Custom Mailchimp Feed

1. Create the feed

In your WordPress dashboard, go to RSS Chimp → Custom Feeds → Add New Feed. Give it a name (e.g. “Mailchimp”) and a slug. The slug becomes the feed URL path, so /feed-mailchimp gives you yourdomain.com/feed-mailchimp. Keep it short and descriptive.

Save the feed. It’s immediately live at that URL — you can paste it into a browser to verify it returns XML.

2. Set the image size

For Mailchimp specifically, the RSS Chimp Medium size (640×360px) works well. It’s a landscape crop that fills Mailchimp’s email container cleanly without being cropped or distorted by the platform.

If you’ve uploaded portrait or square featured images, test a few before committing. Mailchimp renders images at a fixed container width, so a landscape source image is the safest choice.

Under your custom feed settings, go to Image Settings and select RSS Chimp Medium or whichever size fits your content best.

3. Set content length

Decide whether Mailchimp gets full posts or summaries. For most newsletters, summaries work better — the email shows a snippet and a read more link, subscribers click through, and you get actual traffic data from the campaign.

If your newsletter is the primary way subscribers read your content and you want everything in the email, use full post. Under Feed Settings, set content length to whichever you choose.

4. Add UTM parameters

Set these once and every post link in your Mailchimp emails carries them automatically. Under URL Parameters, add:

• utm_source: mailchimp
• utm_medium: rss
• utm_campaign: newsletter (or whatever name makes sense in your GA4 setup)

From that point on, Mailchimp traffic shows up correctly labeled in Google Analytics. No manual tagging per campaign, no mystery direct traffic spikes on send days.

5. Optional: Custom HTML

If you want a consistent footer in every email — a CTA, a sponsor message, a referral prompt — add it under Custom HTML → After Content. It goes at the bottom of every post entry in the feed, which means it appears at the bottom of every post in every Mailchimp email automatically.

Keep it inline-styled. Email clients don’t process external CSS, so anything that relies on a stylesheet won’t render.

Connecting the Feed to Mailchimp

In Mailchimp, go to Campaigns → Create Campaign → Email → RSS. When it asks for the RSS feed URL, paste your custom feed URL (yourdomain.com/feed-mailchimp). Set the send schedule — daily, weekly, or whenever new posts appear — and finish the campaign setup as usual.

The feed URL is the only change from a standard Mailchimp RSS campaign. Everything else works the same way.

Verifying It Works

Open your custom feed URL directly in a browser and check the XML source. You should see:

• Your featured images inside <media:content> or <enclosure> tags in each <item>
• The correct content length in <content:encoded>
• Your UTM parameters appended to the <link> in each item
• Any custom HTML you added, at the top or bottom of the post body

You can also run the feed through the RSS Chimp built-in validator under Settings → Feed Validator to catch any structural issues before Mailchimp does.

Start your free 14-day RSS Chimp Pro trial — no credit card required.

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