--- title: Customer.io API Integration on Truto slug: customerio category: Marketing Automation canonical: "https://truto.one/integrations/detail/customerio/" --- # Customer.io API Integration on Truto **Category:** Marketing Automation **Status:** Generally available ## Unified APIs ### Unified Marketing Automation API - **Campaigns** — The campaign represent a campaign in the remote system. - **Contacts** — The contact represent a contact in the remote system. - **Messages** — The message represent a message in the remote system. - **Segments** — Represents a segment of contacts in the remote system. - **Templates** — The template represent a template for marketing asset in the remote system. - **Users** — The user represent a user in the remote system. - **Workspaces** — The workspace represent a workspace in the remote system. ## How it works 1. **Link your customer's Customer.io 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 Customer.io.** The Proxy API is a 1-to-1 mapping of the Customer.io 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 billing events to trigger automated dunning campaigns** — Subscription and billing platforms can push payment failure events and account status changes into their customers' Customer.io workspaces, enabling marketers to build omnichannel dunning journeys without developer intervention. - **Power lifecycle marketing with real-time product behavior data** — Product-led SaaS companies can pipe behavioral events like feature adoption milestones or onboarding completions directly into Customer.io, letting their users' marketing teams build triggered campaigns based on what users actually do in the product. - **Surface email engagement data inside customer success dashboards** — CS platforms can pull message delivery, open, and click data from Customer.io so account managers see the full picture of marketing touchpoints before renewal conversations — without switching tools. - **Sync audience cohorts for targeted in-app and email campaigns** — Analytics and engagement platforms can push dynamically computed user segments into Customer.io, giving marketers precise audience targeting for campaigns without manual list uploads. - **Keep contact profiles enriched with live SaaS platform attributes** — Any B2B SaaS can continuously upsert user attributes like health scores, plan tiers, or usage metrics into Customer.io contacts, ensuring marketers always segment on fresh, accurate data. ## What you can build - **Bi-directional contact and attribute sync** — Continuously upsert user profiles with custom attributes like MRR, plan tier, and last activity date into your customers' Customer.io workspaces, and read contact data back for display in your own UI. - **Behavioral event forwarding engine** — Push named product events (e.g., invoice_failed, feature_activated) from your platform into Customer.io so end users can use them as journey entry triggers without writing code. - **Campaign and message engagement timeline** — Fetch message-level delivery, open, click, and unsubscribe metrics from Customer.io and render them as a native activity timeline or ROI dashboard inside your product. - **Segment audience sync** — Create and update Customer.io segments from cohorts defined in your platform, enabling marketers to target precise user groups for campaigns without manual CSV imports. - **Workspace-aware environment routing** — Read workspace metadata from Customer.io to let end users map your platform's staging and production environments to the correct Customer.io workspace during setup. - **Transactional message trigger with dynamic variables** — Let your users fire API-triggered transactional emails or SMS through Customer.io, passing custom Liquid variables like secure links or invoice amounts at send time. ## FAQs ### What authentication method does Customer.io use? Customer.io uses API key-based authentication. The Track API uses a Site ID and API Key pair, while the App API uses a separate App API Key. Truto handles storing and managing these credentials so your end users authenticate once during the connection flow. ### Does Customer.io have separate APIs for reading and writing data? Yes. Customer.io splits its API into two distinct surfaces: the Track API (and Pipelines API) for ingesting contacts, attributes, and events, and the App API for reading campaigns, messages, segments, and workspace metadata. Truto abstracts this split behind a single unified interface. ### Are Customer.io tools available today in Truto? Customer.io integration tools are built on request. Once requested, Truto builds and exposes them through the Unified Marketing Automation API, covering resources like Campaigns, Contacts, Messages, Segments, Templates, Users, and Workspaces. ### How does Truto handle Customer.io's rate limits and pagination? Truto manages rate limiting and pagination automatically. When you query resources like messages or contacts through the Unified API, Truto handles page cursors and respects Customer.io's rate limits transparently, so your application never needs to deal with retry logic or partial responses. ### Can I sync custom attributes and events that aren't part of a standard schema? Yes. Customer.io supports highly flexible custom attributes on contact profiles and arbitrary named events. Truto's Unified API passes through custom fields and event properties, so your integration isn't limited to a fixed set of attributes. ### What Unified API resources map to Customer.io capabilities? Truto's Unified Marketing Automation API covers Campaigns, Contacts, Messages, Segments, Templates, Users, and Workspaces — mapping to Customer.io's core concepts for managing audiences, triggering communications, and reading engagement data.