Klaviyo Year-End Review: Analyzing Your Email Performance

The year is winding down and your Klaviyo account has 12 months of data sitting in it. Most brands will ignore that data, set a vague goal to "do more email" next year, and repeat the same patterns that produced the same results.

Don't be most brands.

A proper year-end review takes 2-3 hours and gives you clarity on exactly what's working, what's broken, what's missing, and where next year's email revenue growth will come from. It turns a year of sending into a strategic blueprint for the next year.

I'm going to walk you through the exact audit we run for our Klaviyo clients every December. By the end of this post, you'll have a checklist, a framework for interpreting your data, and a clear set of priorities for the year ahead.

Part 1: The Revenue Overview

Start with the big picture. Go to Klaviyo's Analytics Dashboard and set the date range to the full year (January 1 through December 31).

Total email-attributed revenue. This is your headline number. How much revenue did Klaviyo generate this year? Note: Klaviyo uses a 5-day click attribution window and a 5-day open attribution window by default. Some of this revenue would have happened anyway. But it's still the benchmark for year-over-year comparison.

Write down: Total revenue, revenue from flows, revenue from campaigns.

Revenue trend by month. Look at the monthly breakdown. Is revenue growing month-over-month? Flat? Declining? Are there seasonal spikes (BFCM, Valentine's, summer) that you planned for, or were they organic?

Write down: Highest revenue month, lowest revenue month, YoY growth rate.

Revenue split: flows vs. campaigns. What percentage came from flows vs. campaigns? The healthy split is roughly 50/50. If flows dominate, you're not sending enough campaigns. If campaigns dominate, your flows are underbuilt.

Write down: The percentage split and whether it's changed from last year.

Part 2: Campaign Performance Audit

Pull your campaign analytics for the full year. Sort by revenue, then by engagement.

Top 5 campaigns by revenue. What do they have in common? Was it the offer? The subject line? The segment? The timing? Look for patterns. If all your top campaigns were discount-driven, that tells you something. If they were launch announcements, that tells you something different.

Bottom 5 campaigns by engagement. What went wrong? Low open rate usually means bad subject line or bad timing. Low click rate with decent opens means the content didn't deliver on the subject line's promise. Low revenue with decent clicks means the landing page or offer was weak.

Campaign frequency analysis. How many campaigns did you send per month? Per week? Was there a correlation between send frequency and engagement rates? Many brands fear sending too often, but the data usually shows that 3-4 campaigns per week performs better than 1-2 (as long as content quality stays high).

Subject line analysis. Look at your top 20 campaigns by open rate. What subject line patterns appear? Short vs. long? Question vs. statement? Emoji vs. no emoji? Personal vs. promotional? This data tells you what resonates with your specific audience.

Part 3: Flow Performance Audit

Go through each active flow and record its performance metrics.

Abandoned Cart Flow

The money flow. Metrics to record:

• Revenue generated (full year)
• Revenue per recipient
• Open rate (first email)
• Click rate (first email)
• Recovery rate (% of cart abandoners who purchased)
• Number of emails in the flow
• Whether SMS is included

Questions to ask: Is the recovery rate above 5%? If not, the flow needs work. Has performance improved or declined over the year? Are there enough emails in the sequence (4-5 is optimal)?

Welcome Series

First impressions matter. Metrics to record:

• Conversion rate (subscribers who purchase within the series)
• Revenue per recipient
• Open rate progression (email 1, 2, 3, etc.)
• Dropout rate (where people stop engaging)

Questions to ask: Is the conversion rate above 3%? Does engagement drop off sharply after email 1 (meaning subsequent emails aren't compelling enough)? Is the series the right length?

Post-Purchase Flow

Retention driver. Metrics to record:

• Cross-sell revenue
• Review request submission rate
• Repeat purchase rate within 30/60/90 days for customers who went through this flow

Questions to ask: Are you cross-selling effectively? Is the flow leading to repeat purchases? Are you collecting enough reviews?

Browse Abandonment

High-volume, lower-intent. Metrics to record:

• Revenue generated
• Revenue per recipient
• Click rate

Questions to ask: Is this flow active? (Many brands never build one.) Is it generating meaningful revenue relative to its volume?

Winback Flow

Re-engagement. Metrics to record:

• Reactivation rate (% of lapsed customers who repurchase)
• Revenue per recipient
• Time delay settings (when does it trigger?)

Questions to ask: Is the trigger timing aligned with your actual purchase cycle? Is the offer strong enough?

Flows that should exist but don't. Review this list against your account:

• Abandoned cart (must have)
• Welcome series (must have)
• Post-purchase (must have)
• Browse abandonment (should have)
• Winback (should have)
• Sunset/re-engagement (should have)
• Back in stock (nice to have)
• Birthday/anniversary (nice to have)
• VIP acknowledgment (nice to have)
• Replenishment (nice to have, if applicable)
• Price drop (nice to have)

Any missing flow is a revenue opportunity for next year. Prioritize building the "must have" and "should have" flows first.

Part 4: List Health Assessment

List size and growth. How much did your list grow this year? Track: starting size, ending size, net growth, gross additions, and total removals (unsubscribes + bounces + suppressions).

A healthy list grows by 20-40% per year through organic acquisition. If growth is under 10%, your signup mechanisms need attention.

Engagement distribution. Create a segment of subscribers who have opened or clicked in the last 90 days. What percentage of your total list is in this engaged segment?

Healthy: 35-50% engaged in last 90 days. Concerning: Under 25% engaged. Critical: Under 15% engaged.

If your engagement distribution is concerning or critical, your list has a quality problem. You're carrying too many dead profiles that hurt your deliverability.

Signup source quality. Look at which signup sources (popup, footer form, checkout, landing page) produce the most engaged subscribers over time. Not just the most signups — the best subscribers. Some sources produce high volume but low quality. Others produce fewer but more valuable subscribers.

Part 5: Deliverability Check

Bounce rate trend. Has your bounce rate increased over the year? Rising bounces indicate list decay (old addresses becoming invalid over time). If you're not regularly cleaning your list, bounces will creep up.

Spam complaint trend. Any spikes in spam complaints? These often correlate with specific sends (bad segment, poor content, too aggressive offer). Identify the offending campaigns and avoid repeating those patterns.

Open rate trend (with MPP context). Has your open rate changed? Remember that Apple MPP inflates open rates, so the "true" open rate (from non-Apple clients) is a better indicator of deliverability health.

Part 6: Building Next Year's Strategy

Now that you have the data, build the plan:

Priority 1: Fix what's broken. Flows with below-average performance. Deliverability issues. List health problems. These get fixed in Q1 before you build anything new.

Priority 2: Build what's missing. Flows that don't exist yet. Segments you haven't created. A/B tests you haven't run. These get built in Q1-Q2.

Priority 3: Optimize what's working. Your top-performing flows and campaigns can be refined. Better subject lines, better content, better segmentation. This is ongoing throughout the year.

Priority 4: Experiment with new. New channels (SMS if not already active), new content formats (plain text, interactive), new strategies (localization, VIP programs). Test in Q2-Q3 when your base program is solid.

The Annual Planning Document

Create a one-page planning document for your email program with:

Revenue targets:

• Total email revenue target (20-30% above this year)
• Flow revenue target
• Campaign revenue target
• Revenue per recipient target

Tactical goals:

• Number of campaigns per week
• Number of new flows to build
• A/B tests per month
• List growth target

Calendar milestones:

• Q1: Fix and build foundation
• Q2: Optimize and test
• Q3: Scale and automate
• Q4: Maximize (BFCM prep, holiday campaigns, year-end push)

Monthly review commitment: Schedule a 30-minute monthly review to check progress against these targets. Don't wait until next December to discover you're off track.

The Metrics Dashboard

Set up a monthly tracking spreadsheet with these columns:

• Month
• List size
• Net list growth
• Campaigns sent
• Campaign avg open rate
• Campaign avg click rate
• Campaign revenue
• Flow revenue
• Total email revenue
• Email revenue as % of total store revenue
• Unsubscribe count
• Spam complaints

Fill this in monthly. The trends tell you everything. A brand whose email revenue percentage is climbing from 20% toward 30% is building a healthy, growing channel. A brand whose engagement rates are declining month-over-month despite growing list size is headed toward a deliverability crisis.

The year-end review isn't busywork. It's the difference between brands that grow their email revenue 40% year-over-year and brands that stay flat wondering why "email isn't working." The data is already in your account. You just need to look at it, understand it, and act on it.

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Want us to run a full Klaviyo audit and build your email strategy for the year ahead? Book a free strategy call and we'll turn your data into a growth plan.