Real-time
Two-way sync
Changes in Bill or Klaviyo instantly reflect in both systems. No stale data, no manual imports.
Accounting and finance ⇄ Business productivity
Bill to Klaviyo integration — real-time, two-way sync
Keep Bill 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.
- 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
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Migrated from Celigo
Migrated from Heroku Connect
Migrated from Matillion
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Migrated from Fivetran
Case study
Migrated from Celigo
Why teams connect Bill and Klaviyo
Connect the financial records in Bill with the work happening in Klaviyo, so both stay current without exports or copy-paste.
Bill holds the financial truth: who the customers are, what they were billed, what they paid. Klaviyo is where part of the day-to-day work happens, and that work often involves the same customers and transactions. Without a live connection, the two drift apart, and people end up answering questions from stale copies.
Stacksync keeps Payments, Chart of Accounts, Bank Accounts, Vendor Credits and Credit Memos in Bill and Profiles, Lists, Segments, Events in Klaviyo in sync, bi-directionally and in real time. Whatever records Klaviyo keeps and whatever events it produces, the overlap with Bill is mapped field by field, and a change on either side shows up on the other within seconds.
There is no middleware to build, no API rate limits to babysit, and no nightly job that leaves the morning running on yesterday's data.
Common use cases
- 01 Write Vendors created during ERP onboarding into BILL so new payees are ready to pay without manual re-entry.
- 02 Read Payments and payment status into a reconciliation database once bills are marked paid in BILL.
- 03 Push offline, ERP, or subscription order events into Klaviyo as metrics to trigger post-purchase and win-back flows
- 04 Mirror campaign and flow engagement events into a warehouse for revenue attribution alongside order data
Common sync patterns
Where Klaviyo tracks people or companies: one identity
A customer's details updated in either system update the other, so finance and the rest of the business stop maintaining two versions of the same customer.
Where Klaviyo handles customer conversations: billing context in view
Front-line teams see invoice and payment status from Bill next to the customer they are helping, without logging into the finance system.
Where Klaviyo collects payments or triggers charges: events land in Bill
Payment and charge activity flows into Bill as it happens, so the books reflect reality without manual reconciliation.
What you can sync between Bill 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.
| Bill objects | Klaviyo objects | How this pairing syncs | |
|---|---|---|---|
| Invoices Accounts-receivable invoices sent to customers; created and read via /v3/invoices to keep billing status aligned with the ERP or CRM. | Lists Static audience memberships sync in from CRMs and forms for targeting. | Invoices is specific to Bill and Lists to Klaviyo — each maps to any object or custom field on the other side. | |
| Customers AR customer master records; mapped to customer/account records in a CRM or ERP so finance and sales share one view. | Segments Dynamic audiences are readable so other tools can mirror who qualifies. | Customers is specific to Bill and Segments to Klaviyo — each maps to any object or custom field on the other side. | |
| Payments Outgoing vendor payments and received customer payments; read for reconciliation and created to schedule bill pay. | Events Timestamped behavioral records tied to metrics; external order and product events are pushed in to trigger flows. | Payments is specific to Bill and Events to Klaviyo — each maps to any object or custom field on the other side. | |
| Chart of Accounts GL accounts used to code bills and invoices; typically mastered in the accounting system and written into BILL for consistent coding. | Metrics Event type definitions organize the activity stream used in segmentation and attribution. | Chart of Accounts is specific to Bill and Metrics to Klaviyo — each maps to any object or custom field on the other side. | |
| Bank Accounts Funding and deposit accounts; read to reconcile payments and posted transactions against the ledger. | Campaigns Email and SMS sends expose performance data for warehouse-based reporting. | Bank Accounts is specific to Bill and Campaigns to Klaviyo — each maps to any object or custom field on the other side. | |
| Vendor Credits and Credit Memos AP and AR adjustments applied against bills and invoices; synced so balances stay accurate on both sides. | Flows Automation definitions and their engagement data sync outward for attribution. | Vendor Credits and Credit Memos is specific to Bill and Flows to Klaviyo — each maps to any object or custom field on the other side. |
How changes propagate between Bill 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.
Bill Klaviyo Sub-second propagation
DetectionBill notifies Stacksync of record changes through webhook events. Webhook event subscriptions (POST /v3/subscriptions) for bills, vendors, payments, invoices, and bank accounts, with polling on.
DeliveryEach detected change is written to Klaviyo through its API, with automatic retries and rate-limit backoff.
Klaviyo Bill Sub-second propagation
DetectionKlaviyo notifies Stacksync of record changes through webhook events. Polling on updated timestamps.
DeliveryEach detected change is written to Bill through its API, with automatic retries and rate-limit backoff.
Rate-limit considerations
- Bill: 20,000 requests per developer key per hour; login (POST /v3/login) capped at 200/hour; maximum 3 concurrent requests per developer key per organization. Spend & Expense API is a separate token at 60 calls/token/minute.
- Klaviyo: Per-endpoint burst and steady rate limits apply.
What ships with Bill ⇄ Klaviyo
Connect Bill and Klaviyo for flexible, real-time data sync.
Real-time sync, workflow automation, event queues, EDI, and monitoring, for every Bill–Klaviyo connection.
No-code + pro-code
Workflow automation
Trigger automated workflows whenever Bill 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 Bill or Klaviyo record.
Observability
Monitoring
Track your Bill ⇄ Klaviyo sync health, view errors, and replay failed events in one click.
Trading partners
EDI
Transform legacy EDI complexity into simple database interactions between Bill and Klaviyo.
How the Bill and Klaviyo connectors work
Bill
- Integration surface
- REST/JSON (BILL v3 Connect API)
- Authentication
- Session-based: POST /v3/login with username, password, organizationId, and a developer key (devKey) returns a sessionId that is passed with the devKey as headers on every subsequent call; OAuth is available for partner/embedded apps
- Change detection
- Webhook event subscriptions (POST /v3/subscriptions) for bills, vendors, payments, invoices, and bank accounts, with polling on createdTime/updatedTime list filters as the fallback
- Capabilities
- read · write · webhooks
- Rate limits
- 20,000 requests per developer key per hour; login (POST /v3/login) capped at 200/hour; maximum 3 concurrent requests per developer key per organization. Spend & Expense API is a separate token at 60 calls/token/minute.
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 Bill 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.
- 01
Connect your apps
Authenticate Bill 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.
Bill
connected
Klaviyo
connected
OAuth 2.0SSH tunnelSSL certificateVPC peering - 02
Choose tables
Pick the Bill 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.
objects · Bill ⇄ KlaviyoCustomers 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.
Bill KlaviyoCompany company_name textEmail email textAmount amount numericCreated created_at timestamp
FAQ
Bill and Klaviyo integration FAQ
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Yes. Stacksync provides a managed, real-time two-way integration between Bill and Klaviyo: authenticate both systems, choose the objects to sync (such as Bill's Invoices and Customers), map fields visually, and changes propagate both ways in milliseconds — no code required.
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Stacksync pricing is usage-based and starts at $1,000/month, including the managed Bill and Klaviyo connectors, real-time two-way sync, monitoring, and support. That replaces building and maintaining a custom Bill–Klaviyo integration in-house.
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Yes — Stacksync ships production-grade connectors for both Bill and Klaviyo. 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 Bill: Webhook event subscriptions (POST /v3/subscriptions) for bills, vendors, payments, invoices, and bank accounts, with polling on createdTime/updatedTime list filters as the fallback. On Klaviyo: Polling on updated timestamps; outbound webhooks exist for event topics (availability depends on plan or app-partner status) and as flow webhook actions. Each detected change propagates to the other side in milliseconds, with field-level conflict resolution and an inspectable event log.
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On the Bill side: Payments, Chart of Accounts, Bank Accounts, Vendor Credits and Credit Memos, plus custom fields where Bill exposes them. On the Klaviyo side: Profiles, Lists, Segments, Events. Stacksync auto-detects both schemas and converts types between the two systems.
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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.
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:
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