Acumatica and Mailchimp integration

What moves between them

The flow runs one direction, from Acumatica into Mailchimp. Customer and contact records move from Acumatica into a Mailchimp audience as list members, keyed by email address, so the marketing list reflects the ERP customer master. Posted sales invoices flow from Acumatica into Mailchimp as e-commerce orders under a store tied to that audience, carrying order total, currency, and line items, so campaign reports can attribute revenue to buyers. GL accounts, AP bills, and vendors stay inside Acumatica and are never written to Mailchimp, because Mailchimp has no place to hold them. Mailchimp is treated as a downstream marketing destination, so financial entries are never written back into the ERP.

How ml-connector handles it

ml-connector stores both credential sets encrypted and presents the right auth on each side. On the Acumatica side it accepts the full instance URL and the endpoint version per customer, since Acumatica publishes no shared base URL and a version mismatch returns 404, and it wraps every field value in the required value object. On the Mailchimp side it resolves the data center prefix from the API key suffix or the OAuth metadata endpoint, builds the data-center base URL, and sends the API key over HTTP Basic auth or the non-expiring OAuth token. Acumatica customers and contacts map to Mailchimp list members by email, and posted Acumatica sales invoices map to Mailchimp e-commerce orders under a store linked to the target audience, which ml-connector ensures exists before the first order is written. Because Acumatica is poll-only here, it reads new and changed records on a LastModifiedDateTime filter on the schedule you set, and stores a high-water mark between runs. Mailchimp e-commerce order and customer PUT endpoints behave as upsert, so re-sending the same record by id is safe and does not create duplicates. Members that Mailchimp has marked cleaned will reject a re-subscribe, so those are skipped rather than retried. Acumatica returns HTTP 429 from license-tier throttling and Mailchimp returns 429 when its concurrent-connection limit is hit, so ml-connector backs off and retries within those limits. Every record carries a full audit trail and can be replayed if a downstream call fails.

A real-world example

A mid-sized specialty parts wholesaler with around 150 staff runs Acumatica for inventory, order processing, and finance, while the marketing team runs customer newsletters and promotions in Mailchimp. Before the integration, someone exported a customer list from Acumatica to a spreadsheet every few weeks and imported it into Mailchimp by hand, so the audience was always stale, new customers were missed, and there was no way to tell which campaigns drove actual orders. With the two systems connected, new and updated Acumatica customers flow into the Mailchimp audience automatically, and each posted invoice lands as an e-commerce order, so marketing can see revenue attributed to its campaigns. The manual export step is gone and the audience stays current.

What you can do

• •Sync Acumatica customers and contacts into a Mailchimp audience as list members, keyed by email address.
• •Post Acumatica sales invoices into Mailchimp as e-commerce orders so campaign reports can attribute revenue to buyers.
• •Resolve the Mailchimp data center prefix and bridge Acumatica OAuth with the Mailchimp API key or OAuth token.
• •Read new and changed Acumatica records on a LastModifiedDateTime filter on the schedule you set, with a high-water mark between runs.
• •Use Mailchimp upsert endpoints with retries and a full audit trail so re-sent records never create duplicates.

Questions

Which direction does data move between Acumatica and Mailchimp?

The flow runs one direction, from Acumatica into Mailchimp. Customers and contacts move into a Mailchimp audience as list members, and posted sales invoices move into Mailchimp as e-commerce orders for revenue attribution. Acumatica stays the system of record, and Mailchimp has no general ledger or invoice objects, so nothing financial is written back.

Can Mailchimp store the accounting records from Acumatica?

No. Mailchimp is an email marketing platform with no GL accounts, AP bills, vendors, or true invoice objects. Its e-commerce order, with an order total, currency, and line items, is the closest analog and is used for campaign revenue attribution, not accounting. ml-connector keeps all ledger and AP activity inside Acumatica and syncs only customers, contacts, and sales into Mailchimp.

How does the integration bridge the two different authentication systems?

Acumatica uses OAuth 2.0 against its own per-instance identity server with a version-locked endpoint URL, while Mailchimp uses an API key over HTTP Basic auth or a non-expiring OAuth 2 token tied to a data center prefix. ml-connector stores both credential sets encrypted, resolves the Mailchimp prefix from the key or the OAuth metadata endpoint, and respects each API's HTTP 429 limits with backoff so neither side is overrun.