HubSpot ↔ Mailchimp integration

HubSpot contacts reach the right Mailchimp audience with tags that match their stage, and opens and clicks return to the contact card

Sales keep clients in HubSpot, marketing sends newsletters from Mailchimp, and the two lists drift apart: a client who has already bought still gets the «first order» offer, and a salesperson calling a lead does not know the lead opened yesterday's price email. Exports and imports once a month do not fix it. The HubSpot ↔ Mailchimp pair keeps one picture: contacts and their stage move from HubSpot into the Mailchimp audience as tags, without duplicates, and campaign activity comes back to the contact so sales see who is warm. Below: what moves, which scenarios we cover and what we rely on in both systems.

Request an integration System page: HubSpot →System page: Mailchimp →

What moves between the systems

HubSpot → MailchimpA new or updated HubSpot contact with consent to receive emails is added to the chosen Mailchimp audience or updated there, so a repeated sync does not create a second copy.
HubSpot → MailchimpThe contact's stage, source and owner become Mailchimp tags, and when the stage changes the old tag is removed and the new one set.
HubSpot → MailchimpA HubSpot workflow can start the transfer at the moment you choose, for example when a deal is won, instead of waiting for a nightly run.
Mailchimp → HubSpotCampaign activity, such as which campaign was opened and which link was clicked, returns to the HubSpot contact as a note or property the salesperson sees.
Mailchimp → HubSpotUnsubscribes in Mailchimp are written back to HubSpot, so the contact is not re-added to the audience by the next sync.

What we connect

We agree which HubSpot contacts go to Mailchimp: only those with consent to emails, and which audience each group belongs to.
Together with marketing we fix the list of tags so they match the stages and sources your sales team really uses.
The HubSpot side connects as a private app with its own access key for your account; the Mailchimp side uses a key issued for this connection only.
Before the first full run we compare both lists and show you how many contacts would be added, updated or left out, and start only after your check.

Automation scenarios

Buyers still get the first-order offer

Before the Mailchimp list is exported once a month and does not know who has bought.

After a won deal changes the tag the same day, and the welcome series stops for that client.

Sales call cold

Before the salesperson calls leads in the order they came.

After the contact shows which price email was opened and which link was clicked, and the warm ones are called first.

Duplicates after every import

Before each CSV import adds people who are already in the audience, and some get the same campaign twice.

After the contact is updated in place, and the audience size matches reality.

How it works technically

For those who want to check: each point links to the official documentation page it comes from.

HubSpot's CRM is built around objects — contacts, companies, deals, tickets and others — and every object type has its own numeric ID used in requests.
Source: developers.hubspot.com ↗ checked 2026-09-25
The built-in Workflows builder automates actions — sending an email, updating CRM data, launching another integration — based on an event, a schedule or a condition.
Source: knowledge.hubspot.com ↗ checked 2026-09-25
Privately distributed apps on Free and Starter get 100 requests per 10 seconds per app and 250,000 per day, and the daily limit is shared by all apps in the account.
Source: developers.hubspot.com ↗ checked 2026-09-29
One API request adds a contact to an audience or updates it if it is already there, so a repeated sync does not create duplicates.
Source: mailchimp.com ↗ checked 2026-09-29
Tags on an audience member are added or removed through the API, and a tag that does not exist yet is created when it is first set.
Source: mailchimp.com ↗ checked 2026-09-29
Mailchimp's Marketing API gives programmatic access to account data — enough to sync email activity and campaign analytics with an external system, and to manage audiences and campaigns.
Source: mailchimp.com ↗ checked 2026-09-25

Limits

The limits come from both systems. HubSpot gives a private app on the two lowest plans a fixed number of requests per ten seconds and per day, shared with the other apps in the account, and Mailchimp allows only ten simultaneous connections, so large lists are moved in portions and the first full load can take hours. Consent stays the rule: a contact without permission to receive emails is not sent to Mailchimp, whatever its stage. Activity comes back in batches, so the contact card may show yesterday's opens a little later than Mailchimp itself.

How to start

Three steps from a first message to work on your project.

01
Leave a request
Describe the task in the form — in text or by voice. Budget and timing are optional.
02
We review and estimate
A developer studies the brief, asks about anything unclear and sends an estimate.
03
We start
Once scope and price are agreed, the work begins.

Leave a request

or write to info@coreviaflow.space

Live project We built and run Gemalli — a B2B export platform with producer pages, a CRM and a deal chat. Read the case →

Questions

Which system is the main one for contacts?

HubSpot. Names, stages and owners change there and go to Mailchimp; from Mailchimp only activity and unsubscribes come back, so the two do not overwrite each other.

Will our existing tags be lost?

No. The connection manages only the tags we agree on; tags your marketing set by hand stay as they are.

Can we stay on the entry-level HubSpot plan?

Yes for most small and medium lists: the connection fits the request limits of the lowest plans by moving contacts in portions. We check your volume before starting and tell you if it does not fit.