> ## Documentation Index > Fetch the complete documentation index at: https://docs.vortexiq.ai/llms.txt > Use this file to discover all available pages before exploring further. # Open Rate Trend, Klaviyo > Open Rate Trend for the selected period. Apple Mail Privacy auto-opens make this a directional signal, not an absolute one. How to read it, why it matters, and how to act on it. **Card class:** [Non-Hero](/nerve-centre/overview#card-classes-explained) • **Category:** [Email Marketing](/nerve-centre/connectors#connectors-by-type) > Open rate plotted over time. Apple Mail Privacy Protection auto-opens make the absolute level meaningless, so read the shape of the line, not the number on it. ## At a glance > The time-series of email open rate across the selected period, one point per period bucket. Each point is `opens_unique ÷ delivered` for sends in that bucket. Since Apple's Mail Privacy Protection (MPP) pre-fetches images and registers an open whether or not a human looked, a large and unknowable share of these opens are machine opens. **Treat the absolute level as inflated and the trend line as directional.** A sudden step-change down in this line is far more diagnostic than the headline percentage, it usually flags a deliverability or inbox-placement problem rather than a sudden loss of human interest. | | | | ----------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **What it counts** | Open rate per period bucket, `opens_unique ÷ delivered × 100`, plotted as a line over the selected window. | | **API endpoint + statistics field** | `POST /api/campaign-values-reports` (and `GET /api/metric-aggregates` for the Opened Email metric) returning the `open_rate` statistic, derived from `opens_unique` over `delivered`. | | **Email vs SMS aggregation** | Email only. SMS has no open concept, so SMS sends are excluded from both numerator and denominator. | | **MPP impact** | Heavy. Apple MPP auto-opens inflate `opens_unique`, so the absolute level overstates real human opens, often by 20-40 percentage points for iOS-skewed lists. The trend is still useful because the MPP share is roughly stable week to week. | | **Chart type** | Line. | | **Time window** | `30D vsP` | | **Alert trigger** | A sustained downward step in the trend (rather than a fixed level), which typically signals inbox-placement or reputation issues. | | **Roles** | owner, marketing | ## Calculation Calculated automatically from your Klaviyo data. See the At a glance summary above for what the metric tracks and the worked example below for a typical reading. ## Worked example An illustrative homeware brand sending two to three Klaviyo campaigns a week. Reading the dashboard on 14 Apr 26 for the trailing 30 days (14 Mar 26 to 12 Apr 26), the open-rate line by week looks like this (figures are illustrative, not a real merchant's data): | Week | Delivered | Unique opens | Open rate | | --------------- | --------- | ------------ | --------- | | 14-20 Mar 26 | 41,200 | 18,950 | 46.0% | | 21-27 Mar 26 | 43,800 | 19,710 | 45.0% | | 28 Mar-3 Apr 26 | 40,500 | 14,580 | 36.0% | | 4-12 Apr 26 | 44,100 | 19,400 | 44.0% | ```text theme={null} Week 3 open rate = 14,580 ÷ 40,500 × 100 = 36.0% Step down vs the ~45% baseline = roughly 9 percentage points ``` Five observations: 1. **The 46% headline is inflated by MPP and should not be read as "46% of humans opened".** For an iOS-skewed homeware audience, a large slice of those opens are Apple Mail pre-fetches. The useful information here is that the line normally sits around 45%, not that the level is high. 2. **Week 3's drop to 36% is the real signal.** A nine-point step down in a single week, against an otherwise flat line, is the kind of move worth investigating. Because MPP opens are roughly constant, a drop this size usually means fewer messages actually reached the inbox (more landed in spam or Promotions, or a deliverability dip), not that humans suddenly lost interest. 3. **Always pair the step-down with delivery-rate and bounce data.** If [Delivery Rate](/nerve-centre/kpi-cards/klaviyo/delivery-rate) also dipped in week 3, that confirms an inbox-placement story. If delivery held steady, the cause may instead be a weak send (a poorly targeted segment or a dull subject line) rather than a systemic problem. 4. **Week 4 recovering to 44% suggests the week 3 dip was transient.** A one-week dip that self-corrects is common after a single underperforming campaign. A two- or three-week sustained decline is the pattern that warrants escalation to a deliverability review. 5. **For a cleaner human-interest read, cross-check the click line.** Clicks are not MPP-affected, so if [Click Rate Trend](/nerve-centre/kpi-cards/klaviyo/click-rate-trend) is flat while this open line wobbles, the wobble is almost certainly MPP noise or inbox placement, not a change in real engagement. ## Sibling cards merchants should reference together Open Rate Trend is a directional engagement signal. Pair it with these to separate MPP noise from real movement: | Card | Why pair it with Open Rate Trend | | -------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------ | | [Email Open Rate](/nerve-centre/kpi-cards/klaviyo/email-open-rate) | The single-period headline behind this line. The trend tells you the shape; the headline tells you the latest reading. | | [Click-to-Open Rate](/nerve-centre/kpi-cards/klaviyo/click-to-open-rate) | The MPP-resistant complement. CTOR isolates how compelling the content was for people who actually opened, which the raw open rate cannot. | | [Opened Trend](/nerve-centre/kpi-cards/klaviyo/opened-trend) | The volume view of the same metric. A rising open rate on falling volume tells a very different story than a rising rate on rising volume. | | [Engagement Funnel](/nerve-centre/kpi-cards/klaviyo/engagement-funnel) | The full delivered, opened, clicked, converted cascade. Use it to see where in the funnel an open-rate dip actually bites. | | [Deliverability Drop](/nerve-centre/kpi-cards/klaviyo/deliverability-drop) | The most likely cause of a sustained open-rate step-down. Check this card first when the line drops and stays down. | | [Email Click Rate](/nerve-centre/kpi-cards/klaviyo/email-click-rate) | The cleaner engagement signal. Clicks are real human actions and not inflated by MPP, so they confirm or contradict an open-rate move. | ## Reconciling against Klaviyo **Where to look in Klaviyo:** * Klaviyo → Analytics → Performance, then the open-rate metric over time, for the account-level trend. * Klaviyo → Campaigns, then open a campaign to see its individual open rate, useful for attributing a trend dip to a specific send. * Klaviyo → Analytics, then the Opened Email metric in Metric reporting, which underlies the rate. **Why our number may legitimately differ:** | Reason | Direction of divergence | | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------- | | **Time zone.** Vortex IQ buckets by UTC day; Klaviyo reports in your account time zone. Sends near midnight can fall into a different bucket. | Either direction, usually marginal. | | **Period boundaries.** Vortex IQ uses a 30-day rolling window vs prior; Klaviyo dashboards often default to calendar months. | Either direction. | | **Page caps.** Campaign-values reporting pages at 50 records, so very high-volume accounts may see slight aggregation truncation in a single pull. | Reported rate runs marginally off for very large senders. | | **MPP auto-opens.** Both systems count machine opens, but Klaviyo offers an MPP filter toggle in some views. If you have it on in Klaviyo and we do not, the numbers diverge. | Klaviyo's filtered view reads lower. | | **Campaign vs flow scope.** If the Klaviyo view you compare against is campaigns-only while ours blends campaigns and flows (or vice versa), the rates differ. | Either direction. | ## Known limitations / merchant FAQs **Why is my open rate so high, like 50%+?** Apple Mail Privacy Protection. When an Apple Mail user has MPP on (it is on by default and the majority do), Apple pre-fetches your email images from its own servers, which registers an open whether or not a human ever looked. For iOS-heavy lists this can add 20-40 points of phantom opens. The high number is real machine activity, not real human interest. Read the trend, not the level. **So is the open rate useless?** Not useless, just directional. The MPP share is roughly stable week to week, so the shape of the line still tells you something: a sudden sustained drop almost always means an inbox-placement or deliverability problem, because that is one of the few things that moves opens independently of MPP. For a clean human-interest read, use click rate and click-to-open rate, which MPP does not touch. **The line dropped and stayed down. What do I check first?** Deliverability. Check [Delivery Rate](/nerve-centre/kpi-cards/klaviyo/delivery-rate), [Bounce Rate](/nerve-centre/kpi-cards/klaviyo/bounce-rate), and [Sender Reputation Risk](/nerve-centre/kpi-cards/klaviyo/sender-reputation-risk). A sustained open-rate decline with rising bounces or spam complaints points to a reputation issue. If delivery held steady, look instead at whether you changed segments, subject-line style, or send time. **Does this include flows or just campaigns?** The trend blends both campaign and flow sends by default so it reflects total program engagement. If you want campaign-only or flow-only, filter accordingly in Klaviyo, where campaign-values and flow-values reports are separated. **Why does my number differ from Klaviyo's dashboard?** Usually period boundaries (our 30-day rolling vs Klaviyo's calendar months), time-zone bucketing (UTC vs account zone), or an MPP filter being on in one view and off in the other. Match those settings before treating it as a real divergence. **Can I set an alert on a fixed open-rate threshold?** You can, but a fixed threshold is weak for opens because of MPP inflation. A step-change alert (a sustained drop relative to the recent baseline) is far more meaningful here than a hard floor. Sensitivity is configurable per profile in the Sensitivity tab. *** ### Tracked live in Vortex IQ Nerve Centre *Open Rate Trend* is one of hundreds of KPI pulses Vortex IQ tracks across Klaviyo and 70+ other ecommerce connectors. Nerve Centre runs the detection layer; Vortex Mind investigates the cause when something moves; Ask Viq lets you interrogate any number in plain English. [Start for free](https://app.vortexiq.ai/login) or [book a demo](https://www.vortexiq.ai/contact-us) to see this metric running on your own data.