Real-time
Two-way sync
Changes in AWS S3 or Customer.io instantly reflect in both systems. No stale data, no manual imports.
Data warehouse ⇄ Business productivity
AWS S3 to Customer.io integration — real-time, two-way sync
Keep AWS S3 and Customer.io 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
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Migrated from MuleSoft
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Migrated from Fivetran
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Migrated from Celigo
Why teams connect AWS S3 and Customer.io
Get the data locked inside Customer.io into AWS S3 as live tables, and send results back where Customer.io can use them, without writing a pipeline.
Whatever Customer.io is used for, it accumulates data the rest of the company wants to analyze, and that data usually sits behind an API rather than in the warehouse. Building and babysitting an extraction pipeline is the tax most teams pay for it.
Stacksync syncs Newsletters, People, Objects, Events from Customer.io into tables in AWS S3 continuously, handling schema, rate limits, and retries. Because the sync is bi-directional, results computed in AWS S3 can also be written back into fields in Customer.io where the tool can use them.
Common use cases
- 01 Sync account-level objects and their person relationships for B2B messaging keyed to company attributes.
- 02 Sync product usage and billing attributes from Postgres onto Customer.io people so lifecycle campaigns trigger on real product behavior.
- 03 Archive change history from ongoing syncs as timestamped files for audit and replay.
- 04 Ingest partner or vendor file drops (CSV, JSON, Parquet) from a bucket into a database or CRM as records.
Common sync patterns
Where Customer.io accepts updates: operational write-back
Segments, scores, or reference values computed in AWS S3 sync back onto records in Customer.io, putting analysis where the work happens.
History that outlives the tool
A continuously synced copy in AWS S3 preserves a queryable record even as data ages out of Customer.io or gets changed inside it.
Analytics on Customer.io's data
Records and events from Customer.io land in AWS S3 as queryable tables, current within seconds and ready to join with the rest of the warehouse.
What you can sync between AWS S3 and Customer.io
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.
| AWS S3 objects | Customer.io objects | How this pairing syncs | |
|---|---|---|---|
| Objects The stored files (CSV, JSON, Parquet); syncs read them as datasets or write exports into them. | Objects Non-person entities such as accounts or companies, related to people for account-level messaging. | Same entity on both sides — records pair one-to-one and field-level changes reconcile in both directions. | |
| Object Versions Prior copies retained when versioning is enabled, relevant for reprocessing. | Events Behavioral events sent via the Track API that trigger campaigns. | Object Versions is specific to AWS S3 and Events to Customer.io — each maps to any object or custom field on the other side. | |
| Event Notifications Notifications on object creation or deletion that trigger incremental processing. | Segments Attribute- or event-based groups; data syncs feed the attributes segments evaluate. | Event Notifications is specific to AWS S3 and Segments to Customer.io — each maps to any object or custom field on the other side. | |
| Access Points Scoped network endpoints used to grant a sync narrow access to a bucket. | Campaigns Automated workflows whose membership and metrics can be read via the App API. | Access Points is specific to AWS S3 and Campaigns to Customer.io — each maps to any object or custom field on the other side. | |
| Multipart Uploads The mechanism used to write large export files reliably. | Broadcasts One-off sends to segments or audiences, triggerable via API. | Multipart Uploads is specific to AWS S3 and Broadcasts to Customer.io — each maps to any object or custom field on the other side. | |
| Buckets Top-level containers a sync targets; region and policy are set at this level. | Deliveries / Messages Per-recipient message records whose lifecycle events flow out through reporting webhooks. | Buckets is specific to AWS S3 and Deliveries / Messages to Customer.io — each maps to any object or custom field on the other side. |
How changes propagate between AWS S3 and Customer.io
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.
AWS S3 Customer.io Sub-second propagation
DetectionAWS S3 notifies Stacksync of record changes through webhook events. S3 Event Notifications on object create/delete delivered to SQS, SNS, Lambda, or EventBridge.
DeliveryEach detected change is written to Customer.io through its API, with automatic retries and rate-limit backoff.
Customer.io AWS S3 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 AWS S3 through its API, with automatic retries and rate-limit backoff.
Rate-limit considerations
- AWS S3: Request throughput scales per prefix; sustained high-volume workloads should spread keys across prefixes.
- Customer.io: Subject to per-API rate limits documented by Customer.io.
What ships with AWS S3 ⇄ Customer.io
Connect AWS S3 and Customer.io for flexible, real-time data sync.
Real-time sync, workflow automation, event queues, EDI, and monitoring, for every AWS S3–Customer.io connection.
No-code + pro-code
Workflow automation
Trigger automated workflows whenever AWS S3 or Customer.io 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 AWS S3 or Customer.io record.
Observability
Monitoring
Track your AWS S3 ⇄ Customer.io sync health, view errors, and replay failed events in one click.
Trading partners
EDI
Transform legacy EDI complexity into simple database interactions between AWS S3 and Customer.io.
How the AWS S3 and Customer.io connectors work
AWS S3
- Integration surface
- REST API (the S3 API), accessed directly or through AWS SDKs
- Authentication
- AWS IAM credentials with SigV4 signing; commonly a role scoped to specific buckets and prefixes
- Change detection
- S3 Event Notifications on object create/delete delivered to SQS, SNS, Lambda, or EventBridge; list-based polling as a fallback
- Capabilities
- read · write · webhooks
- Rate limits
- Request throughput scales per prefix; sustained high-volume workloads should spread keys across prefixes
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
How it works
How to connect AWS S3 to Customer.io — 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 AWS S3 and Customer.io with each platform's native method — OAuth, API keys, or service accounts — plus secure options like SSH tunneling, IP whitelisting, and VPC peering.
AWS S3
connected
Customer.io
connected
OAuth 2.0SSH tunnelSSL certificateVPC peering - 02
Choose tables
Pick the AWS S3 and Customer.io 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 · AWS S3 ⇄ Customer.ioCustomers 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.
AWS S3 Customer.ioCompany company_name textEmail email textAmount amount numericCreated created_at timestamp
FAQ
AWS S3 and Customer.io integration FAQ
-
Yes. Stacksync provides a managed, real-time two-way integration between AWS S3 and Customer.io: authenticate both systems, choose the objects to sync (such as AWS S3's Objects and Object Versions), map fields visually, and changes propagate both ways in milliseconds — no code required.
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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.
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Common patterns for AWS S3 and Customer.io: Where Customer.io accepts updates: operational write-back; History that outlives the tool; Analytics on Customer.io's data. Segments, scores, or reference values computed in AWS S3 sync back onto records in Customer.io, putting analysis where the work happens.
-
AWS S3: REST API (the S3 API), accessed directly or through AWS SDKs. Authentication: AWS IAM credentials with SigV4 signing; commonly a role scoped to specific buckets and prefixes. 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. Stacksync manages authentication, retries, and rate limits on both sides.
-
Customer.io: The Track API is ingestion-oriented: integrations identify people and send events, and Customer.io matches records on identifiers such as id or email. AWS S3: The namespace is flat: prefixes only simulate folders, and listing performance depends on how keys are partitioned. Stacksync's field mapping accounts for these differences between AWS S3 and Customer.io without custom code.
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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 AWS S3 and Customer.io 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:
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