Connecting Mailchimp to your Electbase site

What gets sent, and what doesn't

Electbase adds a contact to your audience when someone:

• fills in your sign-up form, your contact form, a yard-sign request, or an endorsement form;
• signs up to volunteer;
• RSVPs to one of your events.

What goes to Mailchimp is the person's email address and a set of tags. Names, phone numbers and addresses are not sent today, because Mailchimp's name and phone fields are set up differently in every audience and a wrong field would make every delivery fail. Every contact gets the tag electbase-website. An RSVP also gets a tag naming the event, like rsvp:Canvass launch, so you can segment by event.

A person with no email address can't be added, because Mailchimp keys everything on email. Someone who signs up twice is one contact, not two.

Double opt-in, and why your sending domain matters

By default Electbase adds each new contact as pending, and Mailchimp emails them a confirmation. They join your audience when they click it. This is the right default for consent proof and for deliverability, and it is the one Mailchimp recommends.

It also means your list grows only if that confirmation email arrives. Mailchimp sends it from its own shared address unless your domain is authenticated in Mailchimp, and a confirmation from a shared address is routinely filtered as spam. Nobody clicks a message they never saw, so contacts sit pending forever while Electbase shows every signup as delivered.

When you pick your audience, Electbase asks Mailchimp which of your domains are set up and warns you if none is authenticated. "Verified" is not the same setting as "authenticated", and the difference is the whole problem; Your campaign's domain and email, explained walks through it. Fix it in Mailchimp before you rely on the connection.

You can turn double opt-in off in the audience panel, which adds contacts as subscribed immediately. Only do that if your signup form already collects clear email consent.

Connecting it in Electbase

You need a Mailchimp account with at least one audience, and an Electbase plan of Grassroots or above.

1. From your dashboard, open Connections in the top navigation and find the Mailchimp card. Click Connect Mailchimp.
2. You are sent to Mailchimp to sign in and approve Electbase. There are no keys to paste. When you come back, the card shows a yellow Degraded chip reading "no audience selected — signups are held." That is expected: nothing can be sent until you choose where it goes.
3. Under Mailchimp audience, click Choose an audience. Electbase lists the audiences in your account with their contact counts. If the account has none yet, create one in Mailchimp first and load again.
4. Pick the audience, decide whether to keep Ask new contacts to confirm by email (double opt-in) checked, and optionally set a Tag prefix if several Electbase sites will share one audience. Click Save audience. The chip turns green.

Signups that arrived while no audience was chosen were held, not lost. They are sent as soon as you save.

The connection itself costs nothing. Your Mailchimp plan is between you and Mailchimp.

When the card turns yellow

A Degraded chip means deliveries are being held, and the text under it says why:

• No audience selected. Choose one as above.
• Authentication failed. Mailchimp rejected our stored sign-in, usually because it was revoked in Mailchimp. Click Reconnect Mailchimp and approve again. The held signups then drain on their own.

Nothing in a held queue is dropped. A delivery Mailchimp refuses outright, such as a contact with no email address, is recorded so you can see it rather than silently skipped.

Disconnecting

Disconnect Mailchimp on the card destroys our stored sign-in and stops queued deliveries. Your site keeps working, and your audience in Mailchimp is untouched. Mailchimp offers no way for us to revoke the authorization from our side, so finish the job in Mailchimp under Account → Connected Sites and remove Electbase there.

Has this been tested against the real Mailchimp?

Yes. On 2026-09-28 the full round trip ran against Mailchimp's live API: a real contact appeared in a real audience, pending and tagged electbase-website, the confirmation email arrived, and a repeated delivery created no duplicate. That exercise found two real bugs on the way, both fixed before this was turned on for campaigns: a datacenter mismatch that was destroying signups instead of holding them, and the sending-domain problem described above, which is why the warning exists.

One hop has not yet been watched end to end: a signup entered on a live published site and followed all the way into Mailchimp. The delivery code itself was driven with a script against Mailchimp, not from a site form. After you connect, submit your own test signup on your live site and look for it in your audience. If it is not there within a few minutes, contact us.

Quick checklist

1. Make sure your Mailchimp account has an audience and that your sending domain is authenticated in Mailchimp.
2. On your Connections page, click Connect Mailchimp and approve Electbase in Mailchimp.
3. Back on the card, choose your audience, review double opt-in and the tag prefix, and click Save audience.
4. Submit a test signup on your live site and look for it in your Mailchimp audience.
5. If you ever disconnect, also remove Electbase under Account → Connected Sites in Mailchimp.