--- title: Mailchimp API Integration on Truto slug: mailchimp category: Email canonical: "https://truto.one/integrations/detail/mailchimp/" --- # Mailchimp API Integration on Truto **Category:** Email **Status:** Generally available ## Unified APIs ### Unified Marketing Automation API - **Contacts** — The contact represent a contact in the remote system. - **Lists** — The list represent a list of contacts in the remote system. - **Tags** — The tags on a contact in the remote system. - **Users** — The user represent a user in the remote system. ## How it works 1. **Link your customer's Mailchimp account.** Use Truto's frontend SDK; we handle every OAuth and API key flow so you don't need to create the OAuth app. 2. **Authentication is automatic.** Truto refreshes tokens, stores credentials securely, and injects them into every API request. 3. **Call Truto's API to reach Mailchimp.** The Proxy API is a 1-to-1 mapping of the Mailchimp API. 4. **Get a unified response format.** Every response uses a single shape, with cursor-based pagination and data in the `result` field. ## Use cases - **Sync event attendees into Mailchimp for automated follow-up** — Event management platforms can push attendee data into their customers' Mailchimp audiences with relevant tags, enabling organizers to trigger pre-event logistics emails and post-event nurture sequences without manual CSV imports. - **Route form and survey submissions directly to Mailchimp lists** — Form builder SaaS products can let users map form fields to Mailchimp merge fields and automatically create contacts on submission, turning every lead-gen form into a live pipeline to their customers' email marketing. - **Tag contacts based on in-app behavior to trigger Mailchimp automations** — Any SaaS product tracking user activity can apply or remove Mailchimp tags in real time — like 'Upgraded to Pro' or 'Churned' — so their customers can build Customer Journeys triggered by product events without writing a single email rule. - **Push CRM deal-stage changes into Mailchimp for lead nurturing** — CRM and sales tools can sync lost or stalled deals into Mailchimp with appropriate tags and custom field data, letting marketing teams automatically run drip campaigns to warm leads back up. - **Keep subscription lifecycle events reflected in Mailchimp audiences** — Billing and subscription platforms can upsert contacts and tag them based on subscription events — trial started, plan upgraded, payment failed, cancelled — so their users can automate lifecycle emails from Mailchimp. ## What you can build - **Mailchimp audience picker and field mapping UI** — Let your users select a destination Mailchimp list and dynamically map your app's data fields to Mailchimp merge fields in a clean, in-app configuration flow. - **Real-time contact upsert on key events** — Automatically create or update Mailchimp contacts whenever a relevant event fires in your product — new signup, form submission, deal stage change — using Mailchimp's upsert-friendly API pattern. - **Behavioral tagging engine for marketing automation** — Apply and remove Mailchimp tags based on user actions inside your app, giving your customers a zero-code bridge between product behavior and email automation triggers. - **Bulk contact sync with tag and merge field enrichment** — Ship a one-click sync that pushes your app's contact list into Mailchimp with all associated custom data and tags intact, eliminating manual exports. - **Subscriber status management dashboard** — Surface Mailchimp subscription statuses — subscribed, unsubscribed, cleaned — directly in your product so users can see which contacts are reachable without switching tabs. ## FAQs ### How does authentication work for Mailchimp integrations through Truto? Mailchimp supports OAuth 2.0. Your end users authorize their Mailchimp account through a standard OAuth flow managed by Truto, so you never handle or store their credentials directly. ### What does Truto's Unified Marketing Automation API cover for Mailchimp? The Unified Marketing Automation API provides standardized access to Contacts (Mailchimp Members), Lists (Mailchimp Audiences), Tags, and Users. This covers the core workflows most SaaS integrations need — listing audiences, upserting contacts, managing tags, and reading user info. ### How does Mailchimp handle contact creation vs. updates? Mailchimp's API supports an upsert pattern using the MD5 hash of the lowercase email address as the identifier. If the contact exists, it updates their merge fields and tags; if not, it creates a new subscriber. This prevents duplicate errors and simplifies sync logic. ### Are custom fields (merge fields) supported? Yes. Mailchimp merge fields — like First Name, Company, or any custom field the user has created — can be read and written. You can fetch available merge fields for a list to build dynamic field mapping UIs in your product. ### What are Mailchimp's API rate limits? Mailchimp enforces a limit of 10 simultaneous connections per user. Truto handles pagination and connection management, but high-volume batch operations should be designed with this concurrency limit in mind. ### What if I need Mailchimp capabilities beyond the Unified Marketing Automation API? Truto builds tools on request. If you need access to additional Mailchimp endpoints — like campaigns, e-commerce data, or automations — you can request them and Truto will extend coverage for your use case.