Switching guide

Move your newsletter from Mailchimp to CodeOutbox

Bring your subscribers over in about ten minutes. People who already opted in stay subscribed, without confirming again. Mailchimp keeps subscribed, unsubscribed and cleaned contacts in one audience. You only need the subscribed ones.

1. Export your subscribers from Mailchimp

In Mailchimp, open Audience → All contacts.
Choose Export Audience, then Export as CSV.
Download the ZIP when it's ready and unzip it. It contains one CSV per contact type. Use the one with your subscribed contacts.

Menus change from time to time. If something looks different, Mailchimp's own export guide has the current steps.

2. Create your list

Start at app.codeoutbox.com with your email, or run npx codeoutbox in your site's folder to add a signup form and create the list in one go. Free for up to 100 subscribers, no card.

3. Import the file

In the dashboard

Lists → Import subscribers. Pick the file and choose “Yes, they subscribed with my old tool”.

From your terminal

With an API key from Settings → API keys:

CO_TOKEN=co_live_… npx codeoutbox import newsletter subscribed_members.csv --confirmed

With your coding agent

With the CodeOutbox MCP server installed, ask: “import subscribed_members.csv into my newsletter, they already opted in”.

What comes across

Email Address, First Name, Last Name and your own merge fields (such as Company) come across and work as merge tags. Mailchimp's internal columns, like MEMBER_RATING, OPTIN_TIME and LEID, are skipped. You can use any column in your emails, like {{first_name | "there"}}.

What stays behind

Campaign history, templates and automations stay in Mailchimp. Recreate your welcome email and follow-ups as short Markdown files in CodeOutbox.

Only import people who signed up to hear from you. If you're not sure about part of the list, choose “Email each of them a confirmation link” instead. They'll be added once they confirm.

4. Swap your signup form

Replace the old embed with a form that posts to CodeOutbox. In your site's folder:

npx codeoutbox --id YOUR_FORM_ID

It detects React, Next.js, Vue, Svelte, Astro or plain HTML and writes a styled form component. Your form id is on the dashboard. No website? Every list also has a hosted signup page you can link to.

5. Send from your own domain

Add your domain under Settings → Sending domains and publish the DNS records it shows. Your emails then come from your own address, which helps them reach the inbox. A short first note (“we've moved our newsletter”) helps readers recognize the new sender.

Start free

Mailchimp is a trademark of its owner. CodeOutbox is not affiliated with, endorsed by or sponsored by Mailchimp. The export steps above were checked against Mailchimp's help center in October 2026 and may change.