Bounce Trend, Klaviyo

Bounce Trend for the selected period. The time-series of bounced emails, hard and soft combined. A rising trend points to list-hygiene or sender-reputation risk. How to read it, why it matters, and how to act on it.

Metrics type: Supporting Metrics • Category: Email Marketing

Bounced emails plotted over time, hard and soft together. The shape of this line is an early read on list hygiene and sender reputation, well before deliverability visibly drops.

At a glance

The time-series of bounced emails across the selected period, combining hard bounces (permanent failures such as an address that does not exist) and soft bounces (temporary failures such as a full mailbox or a transient server issue). A bounce is a message Klaviyo attempted to deliver but the receiving server rejected, which is distinct from a dropped email that was never attempted. The value of a trend line, rather than a single rate, is that it shows direction: a slowly climbing bounce line is one of the earliest signs of a degrading list or souring sender reputation, often visible before delivery rate or engagement falls. Use this card to read the trajectory, the bounce-rate card for the proportion, and the bounce-spike alert for sudden jumps. A creeping rise warrants list hygiene; a sharp jump warrants an immediate reputation check.

What it counts	The count of bounced emails (hard plus soft) per period bucket, plotted as a line over the selected window.
API endpoint + statistics field	POST /api/campaign-values-reports and POST /api/flow-values-reports, returning the bounced statistic (with bounce_rate available) per bucket.
Email vs SMS aggregation	Email only. SMS uses carrier-level delivery and failure handling, tracked separately under the SMS channel.
MPP impact	None. Apple Mail Privacy Protection inflates opens, not bounces, so this line is unaffected by MPP.
Chart type	Line.
Time window	30D vsP
Alert trigger	A sustained upward trend in bounced emails against the recent baseline, which signals list-hygiene or sender-reputation risk building over time.
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 pet-supplies brand that imported an older list segment partway through the month. Reading the dashboard on 14 Apr 26 for the trailing 30 days (14 Mar 26 to 12 Apr 26), the bounce line by week looks like this (illustrative figures):

Week	Delivered	Bounced (hard + soft)	Bounce rate
14-20 Mar 26	94,000	470	0.50%
21-27 Mar 26	95,500	478	0.50%
28 Mar-3 Apr 26	92,000	1,288	1.40%
4-12 Apr 26	96,000	1,632	1.70%

Baseline bounces ~475 per week (~0.50%)
Week 3 jumps to 1,288 and week 4 to 1,632
Bounce rate climbs from 0.50% to 1.70% as the line trends upward

Five observations:

1. The line is flat at roughly 475 bounces a week, then climbs in weeks 3 and 4. The trend, not any single point, is the signal. A steady baseline that starts rising is the pattern this card is built to surface.
2. The rise coincides with an imported older segment. Stale addresses are a classic source of hard bounces, because some recipients no longer exist. The timing points straight at the import as the cause.
3. Hard and soft bounces mean different things. Hard bounces (permanent) suggest invalid or dead addresses and call for list cleaning. Soft bounces (temporary) such as full mailboxes may resolve on their own. A persistent rise driven by hard bounces is the more serious of the two.
4. A rising bounce line threatens reputation, not just this send. Mailbox providers read elevated bounces as a sign of poor list hygiene, which can quietly lower inbox placement for every future send. That is why a creeping trend deserves action before it becomes a Deliverability Drop.
5. The fix is hygiene plus suppression. Clean the imported segment, let Klaviyo suppress hard-bounced addresses, and stop emailing them. Watch Suppressed Profiles rise as the bad addresses are removed and the bounce line settles back toward baseline.

Sibling cards merchants should reference together

Bounce Trend is the trajectory view. Pair it with these to read level, alert, and consequence:

Card	Why pair it with Bounce Trend
Bounce Rate	The proportion behind the line. The trend shows direction; the rate shows whether the level is dangerous right now.
Bounce Spike	The alert layer. A sudden jump in this line is what the spike alert catches and escalates.
Delivery Rate	The mirror image. A rising bounce trend pulls delivery rate down, so the two move in opposite directions.
Deliverability Drop	The downstream consequence. A sustained bounce rise often precedes a measurable deliverability fall.
Sender Reputation Risk	The composite warning. Rising bounces are one of the inputs to a reputation-risk flag.
Suppressed Profiles	The cleanup view. Hard-bounced addresses get suppressed, so this should climb as the bounce trend is brought under control.

Reconciling against Klaviyo

Where to look in Klaviyo:

• Klaviyo → Analytics → Performance, then the bounced or bounce-rate metric over time, for the program-level trend.
• Klaviyo → Campaigns and Klaviyo → Flows, then a specific send’s analytics, where bounces are broken out per send.
• Klaviyo → Analytics → Deliverability, for the broader reputation context behind a rising line.

Why our number may legitimately differ:

Reason	Direction of divergence
Hard plus soft. This card combines hard and soft bounces. A view filtered to hard bounces only will read lower than ours.	Ours reads higher than a hard-only view.
Time zone. Vortex IQ buckets by UTC day; Klaviyo uses your account time zone. A bounce near midnight can fall into a different period.	Either direction, usually marginal.
Bounce vs drop. This card counts attempted-then-rejected messages, not dropped (never-attempted) messages. A view that conflates the two will not match.	Ours reads lower than a bounce-plus-drop view.
Campaign plus flow scope. This card blends campaigns and flows. A campaign-only view will read lower.	Ours reads higher than a campaign-only view.
Page caps. Values reporting pages at 50 records per pull, so very high send volumes can see slight aggregation truncation.	Ours can read marginally low for heavy senders.

Known limitations / merchant FAQs

What is the difference between this card and Bounce Rate? This card is the trend, the count of bounced emails plotted over time so you can see direction. Bounce Rate is the proportion, bounces as a percentage of attempted sends. The trend tells you whether things are getting worse; the rate tells you whether the current level is dangerous. Read them together.

How is a bounce different from a dropped email? A bounce was attempted: Klaviyo tried to deliver and the receiving server rejected it. A dropped email was never attempted, because the address was already suppressed, invalid, or unsubscribed. They sit at different stages, so they are counted on different cards. See Dropped Emails.

Should I worry more about hard or soft bounces? Hard bounces, generally. A hard bounce is a permanent failure, usually a dead or invalid address, and a rising hard-bounce trend signals a degrading list. Soft bounces are temporary (a full mailbox, a transient server issue) and often resolve on their own. A trend driven by hard bounces is the one to act on.

Why does a rising bounce line hurt sends that did not bounce? Because mailbox providers watch your bounce behaviour as a hygiene signal. Persistently high bounces suggest you are mailing a poorly maintained list, which can lower inbox placement for all your mail, including messages to perfectly valid addresses. The damage is reputational, not just per-send.

The line jumped after I imported a list, is that expected? Often, yes. Imported and older segments tend to contain stale addresses that hard-bounce. The fix is to clean the list, allow Klaviyo to suppress the hard bounces, and avoid re-emailing them. Watch the trend settle back toward baseline as suppression does its work.

Does this include SMS failures? No. This card is email bounces only. SMS uses carrier-level delivery and failure handling, which is reported separately under the SMS channel.

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Tracked live in Vortex IQ Nerve Centre

Bounce 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.

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