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Gmail to Klaviyo integration — real-time, two-way sync

Keep Gmail and Klaviyo in sync without custom scripts. Cut weeks of integration work, eliminate silent data drift, and give your team a single, reliable source of truth.

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Adopted by fast-scaling companies moving mission-critical data in real time

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Why teams connect Gmail and Klaviyo

Sync the people, users, and work records in Klaviyo with the calls, messages, and events in Gmail, in real time and in both directions.

Klaviyo holds the records a team works from: the contacts, the tickets or tasks, the users, and the history attached to each. Gmail moves the actual communication, whether that is a call, a text, an email, or a meeting, and every one of those is tied to a person and often to a user on your side. When the two are connected only by manual entry or a nightly export, the communication happens in one system while the record it belongs to sits in another, so people rebuild context by hand and reach out from contact lists that are already out of date.

Stacksync syncs Campaigns, Flows, Templates, Catalog Items in Klaviyo with Threads, Labels, Drafts, Attachments in Gmail bi-directionally and in real time. Contacts and users maintained in Klaviyo feed Gmail so outbound dialing, messaging, and invites reach current numbers and addresses, and the calls, messages, and meeting events Gmail produces attach to the matching record in Klaviyo within seconds. Everything is mapped field by field, with conflict resolution in place of copy-paste, and there is no middleware to build, no rate limits to babysit, and no batch job that leaves the morning running on yesterday's data.

Because the sync is field-level, each system keeps its own extras; only the shared people, users, and activity are held in agreement.

Common use cases

  • 01 Mirror campaign and flow engagement events into a warehouse for revenue attribution alongside order data
  • 02 Keep suppression and consent status consistent between Klaviyo and other email or SMS tools
  • 03 Read Attachments and message metadata into a warehouse or document store for retention, discovery, and compliance reporting.
  • 04 Mirror Labels with pipeline or ticket states so triage done in an external tool is reflected inside the inbox.

Common sync patterns

One contact master

A person's number, email, or contact preferences corrected in either system update the other, so the record and the channel that reaches them stay in agreement.

Where Gmail places calls or sends messages: activity on the record

Calls, texts, emails, or meeting events from Gmail attach to the matching contact, ticket, or item in Klaviyo, so the full history lives with the record instead of in a separate log.

Contacts and numbers kept current for outreach

People and their phone numbers or email addresses maintained in Klaviyo sync into Gmail, so outbound dialing, messaging, and invites always reach current details rather than a stale list.

What you can sync between Gmail and Klaviyo

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.

Gmail objects Klaviyo objects How this pairing syncs
Attachments File payloads referenced by message part; read out to storage or a document system for archival and compliance workflows. Segments Dynamic audiences are readable so other tools can mirror who qualifies. Attachments is specific to Gmail and Segments to Klaviyo — each maps to any object or custom field on the other side.
History The incremental change log keyed by historyId; used for efficient delta sync so only mailbox changes since the last cursor are fetched. Events Timestamped behavioral records tied to metrics; external order and product events are pushed in to trigger flows. History is specific to Gmail and Events to Klaviyo — each maps to any object or custom field on the other side.
Messages Individual emails with headers, body, and label state; read out to a CRM or warehouse for activity logging, and sent or modified two-way from sales tools. Metrics Event type definitions organize the activity stream used in segmentation and attribution. Messages is specific to Gmail and Metrics to Klaviyo — each maps to any object or custom field on the other side.
Threads Conversation groupings that keep replies together; synced so a CRM timeline or support desk shows the full exchange, not isolated messages. Campaigns Email and SMS sends expose performance data for warehouse-based reporting. Threads is specific to Gmail and Campaigns to Klaviyo — each maps to any object or custom field on the other side.
Labels User and system labels (INBOX, SENT, custom); applied and removed via sync to mirror pipeline stages or triage states from an external system. Flows Automation definitions and their engagement data sync outward for attribution. Labels is specific to Gmail and Flows to Klaviyo — each maps to any object or custom field on the other side.
Drafts Unsent messages; created and updated from templates or sequence tools so reps review before sending from their own mailbox. Templates Message templates are accessible via API for content management workflows. Drafts is specific to Gmail and Templates to Klaviyo — each maps to any object or custom field on the other side.

How changes propagate between Gmail and Klaviyo

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.

Gmail Klaviyo Sub-second propagation

DetectionGmail notifies Stacksync of record changes through webhook events. Incremental sync via users.history.list from a stored historyId cursor, plus real-time push notifications through Google Cloud Pub/Sub watch on the.

DeliveryEach detected change is written to Klaviyo through its API, with automatic retries and rate-limit backoff.

Klaviyo Gmail Sub-second propagation

DetectionKlaviyo notifies Stacksync of record changes through webhook events. Polling on updated timestamps.

DeliveryEach detected change is written to Gmail through its API, with automatic retries and rate-limit backoff.

Rate-limit considerations

  • Gmail: Quota is measured in units per user per second (e.g. messages.list = 5 units, messages.send = 100 units) against a 250 quota-unit/user/second limit and a daily project cap; exceeding limits returns 429 with exponential backoff expected.
  • Klaviyo: Per-endpoint burst and steady rate limits apply.
What ships with Gmail ⇄ Klaviyo

Connect Gmail and Klaviyo for flexible, real-time data sync.

Real-time sync, workflow automation, event queues, EDI, and monitoring, for every Gmail–Klaviyo connection.

Real-time

Two-way sync

Changes in Gmail or Klaviyo instantly reflect in both systems. No stale data, no manual imports.

No-code + pro-code

Workflow automation

Trigger automated workflows whenever Gmail or Klaviyo 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 Gmail or Klaviyo record.

Observability

Monitoring

Track your Gmail ⇄ Klaviyo sync health, view errors, and replay failed events in one click.

Trading partners

EDI

Transform legacy EDI complexity into simple database interactions between Gmail and Klaviyo.

How the Gmail and Klaviyo connectors work

Gmail

Integration surface
Gmail API (REST, v1)
Authentication
OAuth 2.0 via Google — user-authorized consent with granular scopes (gmail.readonly, gmail.modify, gmail.send, gmail.labels); restricted scopes require Google's app verification for production use
Change detection
Incremental sync via users.history.list from a stored historyId cursor, plus real-time push notifications through Google Cloud Pub/Sub watch on the mailbox (watch must be renewed at least every 7 days)
Capabilities
read · write · webhooks
Rate limits
Quota is measured in units per user per second (e.g. messages.list = 5 units, messages.send = 100 units) against a 250 quota-unit/user/second limit and a daily project cap; exceeding limits returns 429 with exponential backoff expected.

Klaviyo

Integration surface
REST API compliant with the JSON:API specification
Authentication
OAuth 2.0 for apps or private API keys
Change detection
Polling on updated timestamps; outbound webhooks exist for event topics (availability depends on plan or app-partner status) and as flow webhook actions
Capabilities
read · write · webhooks
Rate limits
Per-endpoint burst and steady rate limits apply
How it works

How to connect Gmail to Klaviyo — 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.

  1. 01

    Connect your apps

    Authenticate Gmail and Klaviyo with each platform's native method — OAuth, API keys, or service accounts — plus secure options like SSH tunneling, IP whitelisting, and VPC peering.

    • OAuth 2.0
    • SSH tunnel
    • VPC peering
    Gmail connected
    Klaviyo connected
    OAuth 2.0
    SSH tunnel
    SSL certificate
    VPC peering
  2. 02

    Choose tables

    Pick the Gmail and Klaviyo 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.

    • Standard objects
    • Custom objects
    • Auto-schema
    objects · Gmail ⇄ Klaviyo
    Customers 12,480
    Sales Orders 8,213
    Invoices 5,902
    Items 1,344
  3. 03

    Map fields

    Fields map automatically even when names and types differ. Stacksync handles transformation and type casting for you, zero configuration required.

    • Auto-map
    • Type casting
    • Transforms
    Gmail Klaviyo
    Company company_name text
    Email email text
    Amount amount numeric
    Created created_at timestamp
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FAQ

Gmail and Klaviyo integration FAQ

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.

Learn more about security
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:

OAuth 2 SSH Tunnelling SSL certificates IP Whitelisting VPN gateway VPC peering and more

Related integrations

Every pair below is a real-time, two-way sync. Search all 352 integrations available for Gmail and Klaviyo.

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