Lifecycle language combines several different ideas: a contact’s status, an event that occurred, the purpose of a message, and the rules governing an automated sequence. Treating these as synonyms obscures how email systems work. A customer can remain a customer while entering an onboarding sequence, receiving a receipt, or becoming inactive under a separately defined rule. This reference distinguishes lifecycle stages, common message types, trigger conditions, and metric calculations. It attributes platform terminology where definitions differ and uses hypothetical numbers only to demonstrate arithmetic. It does not prescribe a sequence, recommend a sending schedule, rank software, or claim that any message type produces a particular commercial outcome. Legal examples are identified by jurisdiction.
Lifecycle stages are system-specific classifications
A lifecycle stage categorizes a contact’s or company’s relationship with an organization. HubSpot’s default stages include Subscriber, Lead, Marketing Qualified Lead, Sales Qualified Lead, Opportunity, Customer, Evangelist, and Other. Its definitions distinguish a newsletter subscriber from a lead with another qualifying interaction and a customer associated with a closed deal. These are HubSpot’s documented defaults, not a mandatory industry-wide sequence.
HubSpot also allows customized stages, which illustrates why labels alone do not establish comparable populations. “Active,” “retained,” and “lapsed” can be separately defined statuses rather than equivalents of a sales-stage property. A hypothetical lapsed-customer segment might mean no purchase within a stated period; it need not mean that the underlying customer record has changed stage.
Welcome, onboarding, purchase, and reactivation messages
A welcome sequence is associated with a new subscription or similar entry event. Onboarding messages concern initial setup, product use, or account familiarization. Post-purchase messages follow an order-related event, while reactivation or win-back messages address a population defined as inactive. These names describe message contexts; they do not specify one fixed duration, number of messages, or legal classification. Klaviyo’s flow documentation gives examples of subscription, checkout, fulfillment, and date-triggered sequences.
Abandoned-checkout and browse-abandonment labels also depend on tracked activity. Klaviyo documents Started Checkout for a common abandoned-cart flow and Viewed Product for browse abandonment; available events vary with integrations and custom tracking. An event name is not proof that every visitor was identified or that every shopping action was recorded. Its metric-triggered flow documentation defines these examples in platform-specific terms.
Triggers, filters, delays, and exits
A trigger starts a flow when a qualifying condition occurs. Klaviyo documents triggers based on tracked actions, list or segment entry, profile dates, and other supported changes. A filter is an additional eligibility condition, not the initiating occurrence itself. A delay controls when a later step becomes due. Branching rules separate paths according to conditions. Klaviyo’s trigger and filter reference explains these distinct components.
Hypothetical example: a Started Checkout event initiates a sequence, a delay postpones a message, and a rule excluding people who have since ordered prevents that particular reminder. This is an illustration, not a prescribed campaign. Klaviyo documents that profile filters are checked at entry and again before actions; a person can fail an action’s filter and still progress to the next step. Skipping a message and permanently exiting a sequence are therefore not necessarily identical states.
Transactional and promotional describe message purpose
Lifecycle context and message purpose are different classifications. A receipt and a product promotion can both follow a purchase while serving different purposes. In the United States, CAN-SPAM distinguishes commercial email from transactional or relationship messages. For messages mixing promotion with transactional or relationship content, primary purpose is commercial if a reasonable recipient would interpret the subject line as promotional, or if the transactional or relationship content does not appear, in whole or substantial part, at the beginning of the body. An automation label such as “post-purchase” does not determine the legal category. GovInfo: 16 CFR § 316.3, Primary purpose (2025 CFR edition)
The U.S. definition is not a statement of requirements in every jurisdiction. Nor does the existence of a customer record establish universal permission for promotional email. Subscription status, channel eligibility, message purpose, and lifecycle stage remain separate concepts in a factual system description. This article does not supply a legal determination for a particular message. Its technical exchange counterpart, APIs and Webhooks in Marketing Automation, explains how systems transfer status data.
Delivery and bounce calculations
For a specified email send, let S be emails sent, B be recorded bounced emails, and D be successfully delivered emails. Where the report defines delivered as sent minus bounces, D = S − B. Delivery rate = D ÷ S × 100%; bounce rate = B ÷ S × 100%. Mailchimp’s dashboard defines bounce rate using hard and soft bounces divided by total emails sent. Its metric definitions identify that denominator.
Hypothetical arithmetic: if 1,000 emails were sent and 20 bounced, the defined delivered count is 980, the delivery rate is 98%, and the bounce rate is 2%. These are illustrative calculations, not campaign results. A zero denominator makes the corresponding rate undefined. A delivered classification also does not establish inbox placement or human readership. Suppressed records not included in sent emails are not silently added to this formula’s denominator.
Open rate, click rate, and clicks per unique opens
Let O be unique recipients recorded as opening an email and C be unique recipients recorded as clicking at least one tracked link, within the same reporting scope. Open rate = O ÷ D × 100%; unique click rate = C ÷ D × 100%. These delivered-email denominators match Mailchimp’s open and click definitions. Total click events are not substituted for C: one recipient can generate several clicks.
Mailchimp defines clicks per unique opens as the percentage of recipients who opened the email and then clicked a link. Let K be unique recipients recorded as opening and then clicking a tracked link; the corresponding calculation is K ÷ O × 100%, not total click events divided by opens. Do not substitute all unique clickers C unless they match that opener-and-clicker population. Hypothetically, D = 980, O = 245, C = 49, and K = 49 give a 25% open rate, 5% click rate, and 20% clicks per unique opens. O = 0 makes the last ratio undefined. Mailchimp’s flow-report reference defines the metric; these are arithmetic examples, not performance benchmarks.
Tracking limitations and population boundaries
Recorded opens are not direct observations of attention. Mailchimp describes tracking-image downloads, notes that blocked images can prevent recording, and counts qualifying clicks as opens in some circumstances. Automated activity, including Apple Mail Privacy Protection, can inflate reported engagement. Consequently, identical-looking rates can reflect different filtering and tracking conditions. Mailchimp’s tracking explanation documents these limitations without establishing that every recorded open represents a human reading the message.
A single-message denominator also differs from a whole-flow population. One person may receive several messages, so summing delivered message instances does not count unique people. Event counts, recipient counts, and time windows describe different measurement units. An exact report specifies which unit, attribution rule, and period it uses before presenting a percentage. The related Social Media & Email Marketing service page concerns service delivery; these definitions do not promise revenue, retention, or conversion changes.
Frequently asked questions
Are lifecycle stage names standardized?
No. HubSpot supplies documented default stages and supports customization. Other systems and organizations can use different classifications. A label such as “inactive” becomes precise only when its eligibility rule and observation period are stated.
Is a trigger the same as a filter?
No. A trigger initiates entry into a flow after a qualifying occurrence. A filter adds eligibility conditions. In Klaviyo, profile filters are checked at entry and before actions, so entering a flow does not guarantee receiving every message.
What is the denominator of email click rate here?
Successfully delivered emails for the specified send. The numerator is unique recipients with at least one recorded tracked-link click. Repeated clicks by one recipient do not become additional unique clickers, and total messages sent is not substituted for delivered messages.
Does an open prove someone read the email?
No. An open is a tracking record, commonly associated with an image download or inferred from a click. Image blocking can suppress records, while automated activity can inflate them. It is not a direct measurement of comprehension or attention.
Is every post-purchase email transactional?
No. “Post-purchase” identifies timing or context. A message can instead have a promotional primary purpose. Under the U.S. CAN-SPAM framework, purpose and content determine the relevant distinction, not the workflow name or the fact that a purchase occurred.