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Glossary index

Learn and define terms commonly used by Klaviyo and email marketing professionals.


Abandoned cart flow

A metric-triggered flow that begins when someone adds an item to their cart but doesn’t follow through with the purchase. Uses Started Checkout or Added to Cart as the flow trigger.

A/B testing

A method of comparing different options to determine which is the most successful at achieving a goal (e.g., opens, clicks, or purchases).

Active on Site

Metric tracked when a known user is active on your site; requires Klaviyo onsite tracking.

Active on Site rate

The rate at which a known user is active on your site.

Active profile

A profile in Klaviyo that can be messaged and who is not suppressed.

Activity feed

A live feed of customer and site visitor activity reflecting metrics flowing into Klaviyo.

Activity map

This map allows you to visualize how, from where, and how often your customers interact with your brand for any given metric.

Advanced reports

Option within the form, campaign, and flow performance overviews; includes a breakdown of different key metrics for a given form, campaign, or flow over time.

Alphanumeric sender ID

A type of SMS sending number used in the UK and Australia; it cannot send MMS messages or receive any text messages; it can be customized to match your brand.

Average order value

Known as AOV, which is the average spend of a customer in a store on a single order.



A way to retroactively queue qualified recipients to a flow. For instance, if someone subscribed before you set up a welcome flow, then back-populating will take them through the flow.

Best people

A tool that allows you to pinpoint your most engaged profiles for a given metric.

Breaking change

Any modification to or deletion of functionality within an API (typically released in a new revision) that may cause integrations or applications to function abnormally or break.

Browse abandonment flow

A metric-triggered flow that sends when an identifiable browser visits a product page and does not make a purchase.



A single, targeted email sending effort; a one-time send to a pre-established group of contacts.

Call to action

Known as a CTA, in an SMS/MMS, email, ad, or website, a CTA is the language that attempts to get the reader to do something specific.

Capture rate

The rate at which website visitors subscribe to marketing, often through a Klaviyo signup form; also called opt-in rate.

Cart abandonment rate

The percentage of people who add item(s) to their cart and subsequently abandon it before purchasing.

Click rate

The percentage of recipients that clicked an email or SMS divided by the total number of recipients.

Clicked SMS

Metric for when a recipient clicks on a link within an SMS message.

Click through rate

Known as CTR, for ads it is the number of clicks divided by the number of impressions; for email and text message, CTR is the number of clicks divided by the number of opened messages.

Cross-sell flow

A message or series of messages that show customers products similar to one they purchased.


A time-based group of customers or web visitors.


Whether the profile has consented to receive messages from your marketing channels.


The ID of the form that collected a profile's consent (if applicable).


The version of the form that collected a profile's consent; this only applies if you run A/B tests and have multiple variations for the specific form.


The method through which a profile consented to receive marketing from your brand (e.g., via a form, at checkout, etc.).

Consented to receive SMS

Metric for when a recipient confirms that they want to receive your SMS messages.


Getting members of a group to take a desired action, like signing up for a mailing list or buying an item on a website.

Conversion rate optimization

Known as CRO, making changes to a website in order to increase the rate at which visitors take the desired action (typically, making a purchase).

Conversion tracking

A recipient opening or clicking an email or SMS and then taking another action within the conversion period.


Stands for Cellular Telecommunications Industry Association; the CTIA is a trade organization run by wireless companies which established the short code system and provided guidelines against SHAFT.

Custom keyword

A type of keyword that you create in Klaviyo to allow customers to subscribe to your SMS marketing efforts.

Customer lifetime value

Known as CLV, the historic and predictive amounts that a customer may spend.

Custom properties

Fields tied to Klaviyo profiles that you can use to gather additional information about the contacts in your account.

Custom reports

A feature found within your account’s Analytics tab; contains pre-built reports that you can choose from to conduct an in-depth analysis of your performance over time.


Date property-triggered flow

In this type of flow, people qualify to enter if they have a date-based profile property set (e.g., a birthday) and their date falls within the flow’s timeline.


Describes a revision that is set to retire and will remain fully unchanged until it is retired.


When a message is in draft mode, it is not active and will not send.


Email action

An action that allows you to send an individual email within a flow.


Failed to deliver SMS

Metric for when a message is sent but not delivered to the recipient.


When a message is not delivered by a wireless carrier.

First active

The first time that a profile engaged with your account; the date recorded represents the first time the contact was active (e.g., opened or clicked an email, visited your website, made a purchase, etc.)


Also known as an automation, an automated sequence of steps that is set in motion by a single trigger and can be filtered based on specific profile or trigger details.

Flow filter

A tool to restrict who enters a flow based on a profile’s behavior or attributes.

Flow trigger

What causes a flow to start; examples of flow triggers include subscribed to list, added to segment, takes an action, or has date property.


Hard bounce

When an email cannot be delivered due to a permanent reason, such as a misspelled email address.

Hero image

A large header or banner image at the top of a web page.



The external ID that can be used as a primary identifier on the profile — typically used in place of an email address. As of April 2022, this property has a limit of 64 characters. Any characters over the limit will be truncated.



Also known as keyword response, these are words that, when sent by a subscriber, prompt a certain action and an automated response, such as 'STOP'.

Klaviyo ID

A unique ID that you can find by navigating to a profile and looking for the 26-character ID (or 6-character ID in some cases) in the URL.

Klaviyo properties

Default properties in your Klaviyo account.


Last active

The date of the most recent recorded activity that the profile has taken.

Last click

The date of this profile’s most recent recorded clicked SMS message or email.

Last open

The date of this profile’s most recent recorded opened email.

Latest stable

Used to classify the most recent revision introduced to our APIs. All new and/or upgraded integrations and apps should target the latest stable revision.


Also known as an audience, a collection of opted-in profiles in Klaviyo, maintained in the Lists & Segments tab.

List cleaning

The process of removing invalid and/or unengaged contacts from your subscriber list.

List-triggered flow

In this type of flow, people will qualify to enter when they are added to a specific list and will remain in the flow as long as they remain in the list.


When a flow message is in live mode, it is active and will send automatically.

Long number

Also called a long code, it is a type of SMS and MMS sending number consisting of 10 digits and looks like a regular phone number (1-XXX-XXX-XXXX).



When a flow message is in manual mode, it is active in your flow but no messages will automatically send. You will need to manually review and send all scheduled messages.

Merged profile

This metric is recorded on a profile after it is part of a profile merge.


Also called events, these are actions someone can take on your site or in response to a message. Each metric in Klaviyo represents a specific action.

Metric ID

The six-digit ID associated with a given metric.

Metric-triggered flow

In this type of flow, people will qualify to enter when they take a specific action (e.g., placing an order).


Multimedia message service; this is a type of text message that includes multimedia, such as an image or GIF.


Needs review

If your flow message is (or was at some point) in manual mode, this tab shows the total number of people who are ready to receive the message; messages to this group will not send automatically, so you must review them first.

Non-breaking change

Any addition or modification to an API (in a newly released or pre-existing revision) that does not have the potential to cause breakages.

Notification action

A flow action that sends an email to up to five people, typically used to send internal notifications to a certain team within your organization.


Onsite tracking

Refers to Klaviyo's Active on Site and Viewed Product metrics which track user activity on your site, and can be enabled via the addition of code snippets to your site.

Owned marketing

An approach to marketing where a company focuses strategically on channels that they control, utilizing the data they have in order to create and strengthen customer relationships.

Owned revenue

The revenue attributed to messages sent through Klaviyo.

Open rate

The number of recipients who opened an email divided by the total number or recipients.


Performance dashboard

Dashboard view that gives a detailed overview of how your different communication channels perform as well as suggestions for areas of improvement.

Predictive analytics

The contact's customer lifetime value (including historic, predicted, and total CLV), churn risk prediction, average time between purchases, and order timeline.

Price drop-triggered flow

In this type of flow, people qualify to enter when an item they've viewed or started checkout with lowers in price.

Product feed

Blocks that automatically generate product recommendations by pulling product information from ecommerce integrations.


A comprehensive record maintained for every contact in your Klaviyo account.

Profile property

A characteristic associated with a contact’s profile that you can use to create robust segments, trigger flows, craft targeted messaging, and more.

Post-purchase flow

A metric-triggered flow sent to customers after they complete a purchase; examples include thank you, up-sell, and cross-sell flows.


Quiet hours

The hours during the day you should avoid sending your SMS or MMS messages to your subscribers; is a feature enabled by Klaviyo


Received SMS

Metric for when Klaviyo has recorded that your recipient has received an SMS.


Refers to a revision that is no longer supported. Any API calls using a retired revision header will fall-forward to the oldest, not-yet-retired revision, unless you opt out.

Return on investment

Known as ROI, the ratio of how much a customer spends on Klaviyo compared to how much Owned Revenue they generate.

Revenue per recipient

Known as RPR, the revenue from a campaign or flow divided by the number of recipients in that campaign or flow.



A collection of profiles in Klaviyo, maintained in the Lists & Segments tab, that is defined by a set of conditions.

Segment-triggered flow

In this type of flow, people qualify to enter when they are added to a segment that triggers the flow and will remain in the flow as long as they remain in that segment.

Sent SMS

Metric for when someone texted your destination number to subscribe.


Stands for sex, hate, alcohol, firearms, and tobacco; using terms related to SHAFT or anything illegal, including CBD, will cause a message to be heavily filtered by wireless carriers.

Short code

A type of SMS and MMS sending number consisting of a short series of numbers (XXXXX).

Smart sending

If the smart sending feature is enabled, Klaviyo will skip sending your current message to a recipient if they have already received an email or SMS from you within a specified period


Stands for short messaging service; this is a type of text message that includes only text or symbols such as emojis.

SMS action

Flow action used to send a text message; each SMS has a template and settings that can be configured.

SMS consent timestamp

A timestamp that appears on a profile when they subscribe to SMS marketing from your brand.

Social links

A block in Klaviyo's email drag-and-drop email template editor that allows you to provide the links to your social sites in your emails.

Soft bounce

A soft bounce is an email bounce caused by a temporary reason, such as a full inbox or the recipient email server being down momentarily.


The source through which a profile came into your account, captured as a custom property under the Information section of the profile.

Spam complaint rate

The number of recipients who reported an email as spam divided by the total number of recipients.


Describes a revision from its initial release to its deprecation. A revision is considered "stable" for 1 year after its release.

Subscribe keyword

A type of keyword your customers can use to opt into receiving SMS marketing messages from your brand, such as 'JOIN'.

Subscribed to list

The metric recorded when a contact subscribes to a Klaviyo list directly via a Klaviyo form.


Flow used to phase out customers who are no longer engaging with messages from your brand.


The status of a contact once they unsubscribe from an email, an email sent to them hard bounces, or they are manually added to the Suppression List.



Stands for the Telephone Consumer Protection Act; this act covers the use of automated telephone communications, including phone calls, voicemails, fax machines, and text messages.

Time delay

A flow action used to create delays — or wait periods — between components in a flow series.

Toll-free number

A type of SMS sending number consisting of 10 digits starting with an eight (1-8XX-XXX-XXXX).

Total clicks

The total number of times an email or SMS was clicked.

Total opens

The total number of times an email was opened.

Tracking pixel

Code added to a website that sends tracking information back to a source.


A type of message sent as a function of the purchasing process; for example, an order confirmation email or a shipping notification.

Trigger filter

A tool to restrict who enters a flow based on data associated with the triggering event.

Trigger split

A component that creates two distinct paths in your flow, branching based on a defining characteristic of the trigger.


Unsubscribe rate

The number of recipients who unsubscribed divided by the total number of recipients for a message.

Unsubscribed from SMS

Metric for when a recipient texts STOP and unsubscribes from your SMS messages.

Update profile property action

An action in a flow that allows you to create, update, or delete a custom property from a profile.


Vanity short code

Type of short code that allows you to choose what the number is (XXXXX).


Waiting queue

A list of profiles scheduled and waiting at a given step in a flow.


The process of establishing a good sending reputation when you first start sending emails with Klaviyo.

Welcome series

Type of flow sent when someone is added to a list or, in certain cases, is added to a segment.

Winback flow

Type of flow aimed at re-engaging lapsed customers.