Real-time
Two-way sync
Changes in Customer.io or SendGrid instantly reflect in both systems. No stale data, no manual imports.
Business productivity
Customer.io to SendGrid integration — real-time, two-way sync
Keep Customer.io and SendGrid 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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Why teams connect Customer.io and SendGrid
Stop re-entering the same information in Customer.io and SendGrid: Stacksync keeps the records they share consistent in real time, in both directions.
Two tools in the daily stack often hold overlapping information: the same people, the same companies, or the same pieces of work, described twice. The tools do different jobs, so consolidating is not the answer; the overlap just needs to stop drifting.
Stacksync syncs Objects, Events, Segments, Campaigns in Customer.io with Segments, Categories, Senders, Single Sends in SendGrid in real time. You choose which records overlap, map the fields that should match, and pick a direction or let changes flow both ways. From then on, an update made in either tool is reflected in the other within seconds, without exports or copy-paste.
Because the sync is field-level, each tool keeps its own extras; only the shared data is held in agreement.
Common use cases
- 01 Land delivery and engagement events (sent, opened, clicked, bounced) from reporting webhooks into a warehouse for attribution analysis.
- 02 Keep unsubscribe and subscription-preference state consistent between Customer.io and the CRM to avoid compliance gaps.
- 03 Write bounces, spam reports, and unsubscribes back to the CRM to keep email opt-in status accurate everywhere
- 04 Stream Event Webhook engagement data into a Postgres database or warehouse for campaign and deliverability reporting
Common sync patterns
Where one tool produces events: mirror them in the other
Payments, replies, messages, or tickets created in one tool can create or update matching records in the other, keeping context in one place.
Where SendGrid is where the team documents or plans: keep its data fed
Information that originates in Customer.io stays current in SendGrid instead of going stale after a one-time paste.
Handoffs between teams
When work started in one tool continues in the other, the shared fields travel with it automatically.
What you can sync between Customer.io and SendGrid
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 | SendGrid objects | How this pairing syncs | |
|---|---|---|---|
| Segments Attribute- or event-based groups; data syncs feed the attributes segments evaluate. | Segments Query-based contact groups whose membership SendGrid computes from contact fields. | Same entity on both sides — records pair one-to-one and field-level changes reconcile in both directions. | |
| Broadcasts One-off sends to segments or audiences, triggerable via API. | List Synced with incremental and full sync per the Stacksync docs. | Broadcasts is specific to Customer.io and List to SendGrid — 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. | Categories Synced with incremental and full sync per the Stacksync docs. | Deliveries / Messages is specific to Customer.io and Categories to SendGrid — each maps to any object or custom field on the other side. | |
| Newsletters Recurring email sends with performance metrics available for reporting syncs. | Senders Synced with incremental and full sync per the Stacksync docs. | Newsletters is specific to Customer.io and Senders to SendGrid — 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. | Single Sends One-off marketing campaigns whose stats are read back for reporting. | People is specific to Customer.io and Single Sends to SendGrid — each maps to any object or custom field on the other side. | |
| Objects Non-person entities such as accounts or companies, related to people for account-level messaging. | Unsubscribe Groups Synced with incremental and full sync per the Stacksync docs. | Objects is specific to Customer.io and Unsubscribe Groups to SendGrid — each maps to any object or custom field on the other side. |
How changes propagate between Customer.io and SendGrid
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 SendGrid 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 SendGrid through its API, with automatic retries and rate-limit backoff.
SendGrid Customer.io Sub-second propagation
DetectionSendGrid notifies Stacksync of record changes through webhook events. Event Webhook posts delivery and engagement events (processed, delivered, open, click, bounce, spam report) to an HTTP endpoint.
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.
- SendGrid: Subject to the platform's API rate limits; contact upserts are batched, asynchronous jobs rather than per-row writes.
What ships with Customer.io ⇄ SendGrid
Connect Customer.io and SendGrid for flexible, real-time data sync.
Real-time sync, workflow automation, event queues, EDI, and monitoring, for every Customer.io–SendGrid connection.
No-code + pro-code
Workflow automation
Trigger automated workflows whenever Customer.io or SendGrid 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 SendGrid record.
Observability
Monitoring
Track your Customer.io ⇄ SendGrid 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 SendGrid.
How the Customer.io and SendGrid 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
SendGrid
- Integration surface
- REST API (v3)
- Authentication
- API key (create in SendGrid Settings > API Keys with Custom Access / Full Access for the objects to sync; key begins with "SG")
- Change detection
- Event Webhook posts delivery and engagement events (processed, delivered, open, click, bounce, spam report) to an HTTP endpoint; contact and list changes are detected by polling
- Capabilities
- read · write · webhooks
- Rate limits
- Subject to the platform's API rate limits; contact upserts are batched, asynchronous jobs rather than per-row writes
How it works
How to connect Customer.io to SendGrid — 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 SendGrid 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
SendGrid
connected
OAuth 2.0SSH tunnelSSL certificateVPC peering - 02
Choose tables
Pick the Customer.io and SendGrid 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 ⇄ SendGridCustomers 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 SendGridCompany company_name textEmail email textAmount amount numericCreated created_at timestamp
FAQ
Customer.io and SendGrid integration FAQ
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Yes. Stacksync provides a managed, real-time two-way integration between Customer.io and SendGrid: authenticate both systems, choose the objects to sync (such as Customer.io's Segments and Broadcasts), map fields visually, and changes propagate both ways in milliseconds — no code required.
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Customer.io: Reporting webhooks emit granular message lifecycle events, which is the practical way to get engagement data out at scale. SendGrid: Contact upserts through the v3 Marketing Campaigns API are asynchronous jobs: the API returns a job ID and processes the batch in the background. Stacksync's field mapping accounts for these differences between Customer.io and SendGrid 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 Customer.io and SendGrid records are not retained after a sync operation.
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Stacksync pricing is usage-based and starts at $1,000/month, including the managed Customer.io and SendGrid connectors, real-time two-way sync, monitoring, and support. That replaces building and maintaining a custom Customer.io–SendGrid integration in-house.
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Yes — Stacksync ships production-grade connectors for both Customer.io and SendGrid. The connectors handle authentication, schema detection, rate limits, and retries; you configure the sync, and Stacksync operates it.
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Change detection on Customer.io: Reporting webhooks push message and delivery events; person attribute changes are not streamed and require source-side detection. On SendGrid: Event Webhook posts delivery and engagement events (processed, delivered, open, click, bounce, spam report) to an HTTP endpoint; contact and list changes are detected by polling. Each detected change propagates to the other side in milliseconds, with field-level conflict resolution and an inspectable event log.
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
CSA STAR
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
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