Real-time
Two-way sync
Changes in Customer.io or Kustomer instantly reflect in both systems. No stale data, no manual imports.
Business productivity ⇄ CRM
Customer.io to Kustomer integration — real-time, two-way sync
Keep Customer.io and Kustomer in sync without custom scripts. Cut weeks of integration work, eliminate silent data drift, and give your team a single, reliable source of truth.
- SOC 2 and 6 other compliance frameworks
- POC with real engineers in minutes
Adopted by fast-scaling companies moving mission-critical data in real time
Case study
Migrated from MuleSoft
Case study
Migrated from Celigo
Migrated from Heroku Connect
Migrated from Matillion
Case study
Migrated from Fivetran
Case study
Migrated from Celigo
Why teams connect Customer.io and Kustomer
Sync what happens in Customer.io with the customer records in Kustomer, in real time and in both directions.
The CRM is supposed to be the record of every customer relationship, but customer-relevant information also accumulates in the other tools a team runs. Whatever Customer.io holds or produces that touches a customer, whether conversations, payments, replies, enriched data, or notes, the CRM only benefits if it arrives without someone copying it over.
Stacksync connects Segments, Campaigns, Broadcasts, Deliveries / Messages in Customer.io to Tags, Notes, Customers, Conversations in Kustomer with bi-directional, real-time sync. Activity and record changes in Customer.io update the matching contact or account in Kustomer, and CRM data flows the other way wherever Customer.io can store and use it.
Common use cases
- 01 Keep unsubscribe and subscription-preference state consistent between Customer.io and the CRM to avoid compliance gaps.
- 02 Sync account-level objects and their person relationships for B2B messaging keyed to company attributes.
- 03 Push order and shipment records from commerce systems into Kustomer custom objects so agents answer order-status questions without switching tools
- 04 Mirror conversations and satisfaction data into a warehouse for support analytics and agent performance reporting
Common sync patterns
Where Customer.io can store CRM context: fields kept current
Owner, lifecycle stage, or account details from Kustomer sync into Customer.io, so people working there have the context without switching tools.
Where Customer.io handles support or shared inboxes
Tickets and conversations attach to the right contact and account in Kustomer, so sales sees open issues before the next call.
Where Customer.io runs outreach
Prospects, sends, and replies sync into Kustomer, keeping lead status current without manual imports.
What you can sync between Customer.io and Kustomer
Representative objects on each side — any object or custom field can map to any target. Schemas are auto-detected; types are converted between the two systems.
| Customer.io objects | Kustomer objects | How this pairing syncs | |
|---|---|---|---|
| Segments Attribute- or event-based groups; data syncs feed the attributes segments evaluate. | Teams Team assignments support routing parity and reporting. | Segments is specific to Customer.io and Teams to Kustomer — each maps to any object or custom field on the other side. | |
| Campaigns Automated workflows whose membership and metrics can be read via the App API. | Tags Labels on conversations and customers sync for categorization and analytics. | Campaigns is specific to Customer.io and Tags to Kustomer — each maps to any object or custom field on the other side. | |
| Broadcasts One-off sends to segments or audiences, triggerable via API. | Notes Internal annotations carry context alongside synced conversations. | Broadcasts is specific to Customer.io and Notes to Kustomer — each maps to any object or custom field on the other side. | |
| Deliveries / Messages Per-recipient message records whose lifecycle events flow out through reporting webhooks. | Customers The central record whose timeline aggregates every interaction; external attributes sync onto it. | Deliveries / Messages is specific to Customer.io and Customers to Kustomer — each maps to any object or custom field on the other side. | |
| Newsletters Recurring email sends with performance metrics available for reporting syncs. | Conversations Support threads across channels sync outward for analytics and CRM context. | Newsletters is specific to Customer.io and Conversations to Kustomer — each maps to any object or custom field on the other side. | |
| People Profiles with attributes, matched on identifiers like id or email; the main write target of data syncs. | Messages Individual messages within conversations support full-thread replication. | People is specific to Customer.io and Messages to Kustomer — each maps to any object or custom field on the other side. |
How changes propagate between Customer.io and Kustomer
Each direction of the sync is driven by what the source system can signal and what the destination accepts — detection, delivery, and expected latency below.
Customer.io Kustomer Sub-second propagation
DetectionCustomer.io notifies Stacksync of record changes through webhook events. Reporting webhooks push message and delivery events.
DeliveryEach detected change is written to Kustomer through its API, with automatic retries and rate-limit backoff.
Kustomer Customer.io Sub-second propagation
DetectionKustomer notifies Stacksync of record changes through webhook events. Outbound webhooks on record events, plus polling for backfill.
DeliveryEach detected change is written to Customer.io through its API, with automatic retries and rate-limit backoff.
Rate-limit considerations
- Customer.io: Subject to per-API rate limits documented by Customer.io.
- Kustomer: Subject to the platform's API rate limits.
What ships with Customer.io ⇄ Kustomer
Connect Customer.io and Kustomer for flexible, real-time data sync.
Real-time sync, workflow automation, event queues, EDI, and monitoring, for every Customer.io–Kustomer connection.
No-code + pro-code
Workflow automation
Trigger automated workflows whenever Customer.io or Kustomer data changes, update records, fire webhooks, or kick off sequences without brittle API scripts.
At scale
Event queues
Handle millions of events per minute without losing a single Customer.io or Kustomer record.
Observability
Monitoring
Track your Customer.io ⇄ Kustomer sync health, view errors, and replay failed events in one click.
Trading partners
EDI
Transform legacy EDI complexity into simple database interactions between Customer.io and Kustomer.
How the Customer.io and Kustomer connectors work
Customer.io
- Integration surface
- REST APIs split by purpose: Track API for data ingestion, App API for campaigns, people lookups, and messages
- Authentication
- Basic auth with site ID and API key for the Track API; bearer token for the App API
- Change detection
- Reporting webhooks push message and delivery events; person attribute changes are not streamed and require source-side detection
- Capabilities
- read · write · webhooks
- Rate limits
- Subject to per-API rate limits documented by Customer.io
Kustomer
- Integration surface
- REST API
- Authentication
- API key used as a bearer token, scoped by role
- Change detection
- Outbound webhooks on record events, plus polling for backfill
- Capabilities
- read · write · webhooks
- Rate limits
- Subject to the platform's API rate limits
How it works
How to connect Customer.io to Kustomer — three steps, no code
Configure and sync within minutes, no code. Whether you sync 50k or 100M+ records, Stacksync handles the queues, infra, and plumbing. Integrations are non-invasive and need zero setup on your systems.
- 01
Connect your apps
Authenticate Customer.io and Kustomer with each platform's native method — OAuth, API keys, or service accounts — plus secure options like SSH tunneling, IP whitelisting, and VPC peering.
Customer.io
connected
Kustomer
connected
OAuth 2.0SSH tunnelSSL certificateVPC peering - 02
Choose tables
Pick the Customer.io and Kustomer objects to sync — Stacksync auto-detects both schemas, including custom fields where the platform exposes them. Sync to existing tables, or let Stacksync create new ones with ideal data types.
objects · Customer.io ⇄ KustomerCustomers 12,480Sales Orders 8,213Invoices 5,902Items 1,344 - 03
Map fields
Fields map automatically even when names and types differ. Stacksync handles transformation and type casting for you, zero configuration required.
Customer.io KustomerCompany company_name textEmail email textAmount amount numericCreated created_at timestamp
FAQ
Customer.io and Kustomer integration FAQ
-
Yes. Stacksync provides a managed, real-time two-way integration between Customer.io and Kustomer: authenticate both systems, choose the objects to sync (such as Customer.io's Segments and Campaigns), map fields visually, and changes propagate both ways in milliseconds — no code required.
-
Yes. Each object mapping can be bidirectional or restricted to a single direction (both systems accept writes). Read-only mirrors, one-way pushes, and full two-way sync can be mixed in the same integration.
-
Common patterns for Customer.io and Kustomer: Where Customer.io can store CRM context: fields kept current; Where Customer.io handles support or shared inboxes; Where Customer.io runs outreach. Owner, lifecycle stage, or account details from Kustomer sync into Customer.io, so people working there have the context without switching tools.
-
Customer.io: REST APIs split by purpose: Track API for data ingestion, App API for campaigns, people lookups, and messages. Authentication: Basic auth with site ID and API key for the Track API; bearer token for the App API. Kustomer: REST API. Authentication: API key used as a bearer token, scoped by role. Stacksync manages authentication, retries, and rate limits on both sides.
-
Customer.io: Beyond people, Customer.io supports non-person objects (for example accounts) with typed relationships to people, enabling account-based messaging logic. Kustomer: API keys are issued as role-scoped bearer tokens, so integration access can be limited to the specific object types a sync touches. Stacksync's field mapping accounts for these differences between Customer.io and Kustomer without custom code.
-
Stacksync is SOC 2 Type II and ISO 27001 certified with HIPAA BAA support. Data is encrypted in transit, and a zero-persistent-storage architecture means Customer.io and Kustomer records are not retained after a sync operation.
SECURITY
Security teams trust Stacksync
As a data company, we understand the importance of keeping your data secure. Stacksync is built with security best practices to keep your data safe at every layer, and is DPF-certified for US, EU, UK and CH data transfers.
SOC 2 Type II
ISO 27001
HIPAA BAA
GDPR
CCPA
DPF US-EU-UK-CH
→ SECURITY WITH BENEFITS
SSO & SCIM
Let your users access Stacksync from your centralized user management systems. Works with Okta, Azure, Google SSO and more.
Alerts
Immediately get alerted about record syncing issues over email, Slack, PagerDuty and WhatsApp. Resolve issues from a centralized dashboard with retry and revert options.
Secure connection options
Securely connects to your systems with:
Related integrations
Every pair below is a real-time, two-way sync. Search all 329 integrations available for Customer.io and Kustomer.
Popular · 7 of 329
-
Customer.io ⇄ Dun And Bradstreet -
Customer.io ⇄ Seismic -
Customer.io ⇄ Xactly -
Customer.io ⇄ Gong -
Kustomer ⇄ Lusha -
Kustomer ⇄ Microsoft 365 -
Kustomer ⇄ Microsoft Dynamics 365
No integrations match .
