Klaviyo Flows API
Klaviyo Flows API — programmatic access to Klaviyo's marketing automation flows and event-triggered campaigns, enabling agents to create, update, and trigger Klaviyo automation workflows, manage subscriber profiles, and track events for behavioral email and SMS marketing at scale.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
SOC2 Type II certified. GDPR compliant with EU data residency option. CCPA compliant. TLS enforced. OAuth2 with scopes for third-party access. Separate public/private API keys is good security design. HIPAA BAA not available.
⚡ Reliability
Best When
You're running a Shopify or e-commerce business and want to programmatically trigger Klaviyo behavioral email/SMS flows based on external system events or custom data.
Avoid When
You need to build complex automation flows via API — Klaviyo flows are best configured in the UI with the API used for data input and event triggering.
Use Cases
- • Agents triggering Klaviyo flows by sending custom events (purchase, subscription, product_viewed) for behavioral marketing automation
- • Profile management — agents creating and updating Klaviyo profiles with custom properties for advanced segmentation
- • E-commerce integration — agents syncing order and cart data to Klaviyo to power abandoned cart and post-purchase flows
- • SMS automation — agents triggering Klaviyo SMS flows for order updates, back-in-stock, and promotional notifications
- • List management — agents adding/removing subscribers from Klaviyo lists and segments based on CRM or external system events
Not For
- • Non-e-commerce use cases — Klaviyo is optimized for e-commerce; use Brevo or Mailchimp for non-commerce marketing automation
- • Transactional email infrastructure — Klaviyo is for marketing email; use SendGrid or Postmark for transactional emails
- • Building flows via API — Klaviyo flows are primarily built in the visual UI; the API is for triggering and managing, not creating complex flows programmatically
Interface
Authentication
Private API key for server-side operations (full access). Public API key (site ID) for client-side tracking only. OAuth2 available for third-party integrations with scoped access. API keys support scope selection from Klaviyo dashboard.
Pricing
Contact-based pricing model. Price increases with list size. SMS billed separately by message volume. Klaviyo is positioned as premium but justified by e-commerce ROI. Annual discounts available.
Agent Metadata
Known Gotchas
- ⚠ API versioning uses date-based headers (revision: 2024-02-15) — agents must pin revision header or risk breaking changes
- ⚠ Rate limits vary significantly by endpoint — Track API is unlimited but Profile API is 75 req/s; handle 429s per endpoint
- ⚠ Profile lookup requires email OR phone OR external_id — agents cannot look up by name alone
- ⚠ Flow triggers fire for every matching event — agents sending the same event multiple times will trigger the flow multiple times
- ⚠ SMS requires explicit opt-in records and compliance with TCPA — agents adding phone numbers must verify opt-in consent was captured
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for Klaviyo Flows API.
Scores are editorial opinions as of 2026-03-06.