How do you let marketers edit custom HTML emails in Mailchimp?
Mailchimp's own answer is its template language: add mc:edit to a region of a custom-coded template and the legacy builder lets marketers change that region. It works, and if Mailchimp is your only ESP it may be all you need. Modular Mail, a CMS for email, does the same job outside Mailchimp with one attribute, data-mm: your developer marks the editable parts, your team fills in fields, and the finished HTML is pasted into Mailchimp's Code your own, or into Braze, Salesforce Marketing Cloud or any other ESP you add later.
Updated 3 November 2026. Book a demo and we'll rebuild one of your Mailchimp emails before the call.
The autumn edit is here
Waxed jackets, wool layers and trail boots for the wet months.
The custom template trade-off in Mailchimp
Mailchimp gives a custom-coded template two homes, and both have a cost. In 2026, Litmus found 78% of teams produce and deploy an email in three days or less; the teams on custom code in Mailchimp usually aren't among them.
Sources: Mailchimp documentation, Paste in HTML to create an email, Import a custom HTML template, Create editable content areas with Mailchimp's template language, Template language reference.
We used to wait three to five days for dev to update our email templates. Now my team builds campaigns in an afternoon. Same custom designs, zero technical dependency.
How it works with Mailchimp
Custom templates in Mailchimp, before and with Modular Mail
| Task | Code your own with mc:edit | Modular Mail with Mailchimp |
|---|---|---|
| Editing content | Marked regions, in the legacy builder only | Anyone on the team, in content fields, in any browser |
| Rules on a field | What the editor allows | Character limits, required fields, approved colours and layouts |
| Editing layout | Open to anyone who can edit the code | Locked in the template |
| Adding a new section | A developer edits the template, or it's rebuilt in blocks | Pick a module from your library |
| Review and approval | Mailchimp's comments on a campaign | Comments on one module, review requests and approval on record |
| Sending, audiences and reporting | Mailchimp | Mailchimp, unchanged |
Mailchimp's details are from its help centre, checked on 3 November 2026.
Questions Mailchimp teams ask
Do Mailchimp merge tags survive export?
Yes. A tag typed into a field, such as *|FNAME|*, exports as written and Mailchimp fills it when it sends. Keep *|UNSUB|* in the footer, because Mailchimp won't send a coded email without it.
Do we still need mc:edit?
No. The editing happens in Modular Mail, so the HTML you paste into Mailchimp is finished. If your template already has mc:edit attributes they do no harm, and your developer can remove them when marking the template.
Does it work with the new builder?
The export is pasted through Code your own, which Mailchimp opens in the legacy builder. The new builder is for emails built from Mailchimp's blocks, and nothing on this page needs it.
Do we need a particular Mailchimp plan?
Mailchimp's docs say Code your own needs a Standard plan or higher. Modular Mail has no plan requirement of its own; it only produces the HTML.
Is there a direct Mailchimp integration?
Not an API connection, and Modular Mail keeps no version history. You copy or download the HTML and paste it in, so there's nothing to break when Mailchimp changes its builder, which it has done more than once.
Can we try it without an account?
Yes. Every template in the library opens in the editor with no sign-up. Fill in a few fields, export, and paste the HTML into Code your own to see it in Mailchimp. Browse the templates
Do we have to leave Mailchimp?
No. Mailchimp keeps the audience, the sending, the automations and the reports. Modular Mail only changes where the email is built.
See your own email in Modular Mail.
Send us a recent campaign. We'll rebuild it before the call, so you can see exactly how your team would work.