How Information Is Exchanged between Klaviyo and Apps

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When you integrate a third-party app with Klaviyo, the two platforms exchange information. Most data exchanged via a Klaviyo integration is one-way; data is pulled into your Klaviyo account so you can leverage a broad scope of your customer's data. This article provides an overview of how information syncs between Klaviyo and your third-party apps.

How Integrations Sync Information to and from Klaviyo 

Your Klaviyo APIs are interfaces where data can be exchanged between Klaviyo and other applications that you'd like to connect with your Klaviyo account. 

Klaviyo generates two types of API keys:

  • Public
    Your Public API Key is sometimes also referred to as your Site ID. Although your public API Key identifies your Klaviyo account, it cannot be used by a third party app to access private information within your Klaviyo account.
  • Private
    Private API keys are used for reading data from Klaviyo and manipulating sensitive objects such as lists. This ensures that updating subscription information and other customer information is secure and private. Private API keys should be treated like your password, kept in a safe place and never exposed to the public. You can generate new Private API Keys for different applications to help trace the source of data being added to your Klaviyo account. This distinction makes it easier to understand and use the data within your Klaviyo account. For example, you can use customer data imported from a reviews app in a way that is distinct from customer data imported from your ecomm integration. 

For more specific information regarding types of Klaivyo API Keys, see the Klaviyo API Reference Guide and our complete API Reference Documentation.

Types of APIs 

API types are defined by a set of protocols. Your Klaviyo account consists of two API types:


REST is a set of protocols that apps can use to exchange messages.  Within Klaviyo, messages exchanged between apps are often in JSON format, which is a structured way to layout the information contained in API messages.  Different types of REST APIs allow you to control specific areas of your Klaviyo account, including: 

    • Metrics
    • Profiles
    • Lists
    • Campaigns
    • Templates
    • Flows

Your Metrics API allows you to manipulate event data within your Klaviyo account. Your Profile API allows you to manipulate Profile data within your Klaviyo account.

Track and Identify APIs

Track and identify APIs allow you to track and identify actions that someone has taken. Most data involved in a Klaviyo sync is one-way; data is often brought into Klaviyo via Track and Identify APIs.  Track APIs can import a tracking action such as a placed order or started subscription. Identify APIs can import identifying data such as a birthday or a gender property.

In order to track events or identify properties in a third-party app, a code snippet may need to be added to the platform in order to sync events or properties back into Klaviyo. In many of Klaviyo's built-in integrations, these code snippets are automatically added to the third party site. For example, when you integrate with Shopify or BigCommerce, the code snippets that allow the installation of signup forms are installed automatically.

Sometimes you will be required to manually add a code snippet to a third-party platform. An example of this is enabling web tracking for your ecommerce store. Once you get your integration set up, you can sync different types of data into your Klaviyo account. 

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