Developer docs · InboxRatio Editorial

Klaviyo email API: SDKs, docs and limits (2026)

Every link below points into Klaviyo's official developer documentation and was checked on 10 September 2026. We record only what the vendor documents — a field we could not verify at the source is left out, never guessed.

From Klaviyo's official docs · checked 10 September 2026

Docs, SDKs and limits

Developer docs: developers.klaviyo.com/en
API reference: developers.klaviyo.com/en/reference/api_overview
SDK languages: Node.jsPHPPythonRubyAs listed in Klaviyo's official SDK docs
Webhooks: Webhook docsWebhooks API limited to Advanced KDP customers and Klaviyo app partners
Rate limits: Per-account fixed-window limits with a burst (1-second) and a steady (1-minute) window; each endpoint's limits are listed in its API reference entry. Source
Pricing page: www.klaviyo.com/pricing

From our feature matrix — documented by the vendor

API, SMTP and sending auth

APIKlaviyo APIs; API available on all plans
SDKs / client librariesOfficial SDKs: server-side Node, PHP, Python, Ruby; mobile iOS Swift, Android, React Native, Expo plugin, Flutter
Public API docsPublic developer APIs referenced on features page
WebhooksFlow webhooks (flow action with custom payload) + system webhooks; Webhooks API access: 'Only Advanced KDP customers and Klaviyo app partners'; 'maximum of 10 webhooks' per account
SMTP APINot stated on fetched pages
SMTP relayNot stated on fetched pages
Transactional emailNot stated on fetched features page
SPF assistanceSPF covered in deliverability FAQ; part of branded sending domain setup
DKIM setupDKIM signature via branded/dedicated sending domain setup
DMARC supportDMARC explained + policy guidance in deliverability FAQ

Features checked 10 September 2026. ✓ documented · ◐ limited or plan-gated · × documented as absent · — not documented. Documentation is not a measured result — see our methodology.

Pricing snapshot

Paid Klaviyo plans start at $30/mo (Email), checked 19 August 2026. Full Klaviyo pricing by volume

Generated from our datasets — every value verified and dated

Frequently asked questions

Where are the official Klaviyo API docs?

Klaviyo's official developer documentation is at https://developers.klaviyo.com/en, and the API reference is at https://developers.klaviyo.com/en/reference/api_overview. Links checked on 10 September 2026.

Does Klaviyo have an SDK for Python?

Yes. Python is among the SDK languages listed in Klaviyo's official docs: Node.js, PHP, Python and Ruby (checked 10 September 2026).

What are the Klaviyo API rate limits?

Per-account fixed-window limits with a burst (1-second) and a steady (1-minute) window; each endpoint's limits are listed in its API reference entry. Source: Klaviyo's official documentation at https://developers.klaviyo.com/en/docs/rate_limits_and_error_handling, checked 10 September 2026.

Does Klaviyo offer webhooks?

Yes. Klaviyo's official docs cover webhook event notifications (Webhooks API limited to Advanced KDP customers and Klaviyo app partners): https://developers.klaviyo.com/en/reference/webhooks_api_overview (checked 10 September 2026).