IIf you’re moving from Mailchimp to Substack, the hard part usually isn’t the new platform.
It’s the archive.
All those past campaigns—launches, tips, updates, long notes—are still useful. But they’re trapped in Mailchimp’s email format. Substack wants clean posts. Nobody wants to rebuild seventy newsletters by hand.
I ran into this while working on content for makensearch.
I didn’t want a messy copy-paste migration. I wanted a path that looked like this:
Mailchimp → WordPress → Substack
WordPress became the cleanup layer. Substack became the publishing destination.
Here’s exactly how that worked.
Why direct Mailchimp → Substack is awkward
Mailchimp exports are built for email clients, not for editorial platforms.
A typical campaign export includes:
- View-in-browser links
- Unsubscribe footers
- Merge tags
- Tracking pixels
- CDN-hosted images
- Table-heavy email layouts
Paste that into Substack and it feels broken. Clean it manually for one campaign and it’s fine. Do it for a full archive and it becomes a project you’ll abandon halfway.
So instead of forcing Mailchimp HTML straight into Substack, I used WordPress as a middle step.
Why Mailchimp content is painful to republish
Mailchimp’s HTML export is made for inboxes, not for WordPress.
You usually get:
- “View in browser” links
- Unsubscribe footers
- Merge tags like *|UNSUB|* and *|MC:SUBJECT|*
- Tracking pixels
- Images hosted on Mailchimp CDNs
- Email table layouts that look odd in a theme
If you paste that straight into a post, it looks broken and feels unfinished. Cleaning one campaign is fine. Cleaning seventy is a weekend you’ll never get back.
The migration process
Step 1: Export campaigns from Mailchimp
Download the HTML/ZIP exports for the campaigns you want to keep. One ZIP with many campaigns is fine.
Step 2: Import into WordPress with the Mailchimp HTML Importer plugin
At first, I tried the normal WordPress route: Tools → Import.
That didn’t work well for Mailchimp campaign ZIPs.
Those exports are full email HTML, not clean blog posts. The default importer couldn’t reliably turn them into posts with:
- the real campaign title
- images saved into the Media Library
- email clutter removed
So instead, I used the Mailchimp HTML Campaign Importer plugin and imported everything from the plugin’s own dashboard.
- Upload the Mailchimp ZIP
- Detect each HTML campaign
- Strip email-only junk
- Pull images into the Media Library
- Create normal WordPress posts
At this stage, the goal is not “perfect final copy.” The goal is usable posts with real titles, readable content, and local images. It helps to upload all the campaigns on the posts section of wordpress
Step 3: Light editorial review
Before sending anything to Substack, I checked:
- Titles
- Opening lines
- Featured images
- Anything that still felt like an email footer
This was much faster than rebuilding posts from scratch.
Step 4: Export from WordPress and move to Substack
Once the all the posts looks clean in WordPress, I exported the posts from tools option, downloaded the file and brought them into Substack.
That gave me:
No need to rewrite the whole backlog
A clean on-site archive in WordPress
A separate Substack presence
Why WordPress in the middle helps
WordPress is good at content hygiene.
You can:
- Store images in your own media library
- Edit posts with a normal editor
- Keep drafts vs published status under control
- Export in a structured way later
Substack is excellent for distribution and reading experience. WordPress is excellent for cleanup and ownership.
Using both is not overkill if you care about the archive.
Who this workflow is for
This Mailchimp-to-Substack migration path is useful if you:
- Have more than a handful of past campaigns
- Want Substack without losing old newsletter content
- Prefer not to hotlink Mailchimp images forever
- Need a temporary or permanent WordPress archive
- Care about cleaner formatting before republishing
If you only have 2–3 campaigns, manual cleanup may be enough. If you have a real history, a structured import saves time.
The tool I used for the WordPress step
For the Mailchimp → WordPress part, I used a plugin I built for this exact job:
Mailchimp HTML Campaign Importer Pro
It takes exported Mailchimp campaign ZIPs and turns them into WordPress posts, with options to clean merge tags, remove unsubscribe blocks, download images, and set post status.
If you’re doing the same migration, that middle step is where most of the pain disappears.
Final takeaway
A Mailchimp to Substack migration doesn’t have to mean rewriting your whole archive.
Use this sequence:
- Export from Mailchimp
- Clean + import into WordPress
- Review quickly
- Move the cleaned posts into Substack
That’s how I turned a messy campaign backlog into something publishable—without spending days on repetitive HTML cleanup.
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