4. How Postflows Works with Klaviyo and Omnisend

Postflows does not send emails directly. Instead, it detects shipping events and forwards them to your email platform - Klaviyo or Omnisend - which then triggers and sends the notification to your customer. This article explains exactly what Postflows sends, how it appears in your email platform, and what data you have available for personalization.

The role of each tool

Tool

What it does

Postflows

Detects shipping events, applies rules, forwards event data

Klaviyo / Omnisend

Receives the event, triggers a flow, sends the email to the customer

Your email templates, send timing, audience logic, and branding all live in your email platform. Postflows only delivers the trigger and the data.

How events appear in Klaviyo

When Postflows sends an event to Klaviyo, it creates a metric with the following naming pattern:

Postflows - {Event Name}

Examples:

  • Postflows - 1. Order Created

  • Postflows - 2. Shipment In Transit

  • Postflows - 3. Out for Delivery

  • Postflows - 4. Shipment Delivered

  • Postflows - 5. Label Created

  • Postflows - 6. Shipment Exception

  • Postflows - 7. Delivery Attempt Failed

  • Postflows - 8. Ready for Pickup

You use these metrics as triggers when building flows in Klaviyo.

How events appear in Omnisend

For Omnisend, events follow this naming pattern:

Postflows V1 - {Event Name}

Examples:

  • Postflows V1 - 4. Shipment Delivered

  • Postflows V1 - 6. Shipment Exception

You use these as custom event triggers in Omnisend automations.

Data available for personalization

Every event Postflows sends includes the following data, available as variables in your email templates:

Order details

  • Order ID and order number (e.g. #1001)

  • Order total and currency

Customer details

  • First name, last name

  • Email address

  • Phone number

Shipping address

  • Full address including city, province, country, and zip code

Line items

  • Product name, SKU, quantity, price

  • Product image URL

  • Variant details

Tracking details

  • Carrier name

  • Tracking number

  • Tracking URL (links to carrier tracking page)

  • Estimated delivery date (when available from the carrier)

Test events

After connecting Klaviyo or Omnisend, Postflows automatically sends a test event for each of the 8 event types. This lets you build and preview your flows in your email platform right away, without waiting for real orders.

You can resend test events at any time from Dashboard > Integrations using the Seed All Events button.

Connecting your email platform

If you haven't connected Klaviyo or Omnisend yet, see the onboarding guide: Setting Up Postflows.

Related articles