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Email A/B variants side by side — B dims as A is highlighted
Email A/B Testing · Kajabi

Helping creators learn what works in email — without fake certainty

Kajabi’s most-requested email gap, redesigned as a learning loop for small lists: vary subject, preview, or body; set the win metric and fallback; apply the winner without overclaiming results.

14 min read

Executive summary

30-second read
Role
Lead Product Designer
Timeline
Apr – Jun 2024
Team
1 designer · 1 PM · 2 eng
Responsibilities
  • End-to-end email A/B testing user experience, from entry through winner states
  • Owned competitive synthesis across 8 email service providers → product decisions
  • User testing and interviews; co-authored Messaging & CRM strategy; PRD scope with PM/eng
Business outcome
  • Closed a top expected gap: 84% who saw email in the third-party tool survey expected A/B from Kajabi — it was still missing.
  • Shipped one-off email A/B through v2, then pivoted from interviews (specific-link click wins + click report).
  • Aimed at 2024 parity & retention and brand & GMV goals — not claimed as measured GMV wins.
Design outcome
I designed a reusable A/B system others could use: set up variants, choose how a winner is picked (and a backup if A and B tie), and compare results clearly — without overclaiming wins on small lists. The same system was reused for landing page A/B testing.

My role & constraints

Lead Product Designer on Email A/B with 1 designer, 1 PM, and 2 eng.

Owned: end-to-end UX, competitive review of 8 email tools, testing and interviews, and A/B patterns later reused for landing pages.

Co-led: scope with PM and eng for one-off and automation email.

Constraint: ship on the existing editor; a fuller redesign stayed a separate track (Decision 04).

Business context

79% of creators use Kajabi email; 59% send at least weekly. They need to see what worked so the next email can do better — yet 30% of high-earning creators said email falls short, and 29% already pay other tools (Mailchimp, ConvertKit, ActiveCampaign) about $187/mo for more advanced email features.

In the Messaging & CRM strategy I co-authored, established creators who love Kajabi ranked email the #2 area to improve. In the third-party tool survey, 84% who saw the email category expected A/B testing from Kajabi — and it was still missing. So we designed email A/B as a simple way for small lists to learn, not a copy of big email platforms’ statistical testing.

84%

of creators who saw the email category in the third-party tool survey expected A/B from Kajabi

29%

use marketing/funnel tools outside Kajabi

$187

avg monthly spend on those email tools

The problem

Before email A/B testing, creators couldn’t try two versions of an email inside Kajabi before sending to their whole list. Most A/B tools are built for big audiences; most Kajabi creators don’t have that — and many already don’t trust the email numbers they see.

What creators wanted

  • A/B testing built into Kajabi — expected, and still missing.
  • A simple way to learn: try a different subject, preview, or body → see which got more opens or clicks → use the better one → improve the next email. Clear answers (“Did this do better?”).

Why we couldn’t copy other tools

Big email platforms design A/B for marketers with thousands of subscribers. Most Kajabi creators don’t — so we designed for our users (see Insights), not statistical significance theater.

Insights

This came from the Messaging & CRM strategy I co-authored (including risks we planned for), a survey about tools creators use outside Kajabi, creator interviews, and a review of A/B in 8 email tools.

  1. 01 · Outside-tools survey · Messaging & CRM appendix

    Creators expected A/B testing — and Kajabi still didn’t have it

    84% of creators who saw the email category expected A/B testing from Kajabi. 29% already paid other tools (~$187/mo) for stronger email features; only 32% called A/B their “most important” feature on those tools — so the real gap was catching up inside Kajabi and earning trust, not building a niche power-user feature.

    Led to Decision 02 — let creators test subject, preview, or body as a normal feature, not subject-line-only behind a paid add-on.

  2. 02 · Strategy risks · creator interviews

    Small lists can’t support fake “sure” winners

    Most creators don’t have enough people on their list for a quick, sure winner. Numbers can also disagree (more opens, fewer clicks). Interviews backed a simple job: show what got more engagement — not a stats class.

    Led to Decision 01 — creators pick how a winner is chosen, plus a backup if A and B tie. Same honest approach we saw in the Braze review.

  3. 03 · Strategy risks · low trust in analytics

    Messy results need creator control — and clear wording

    Strategy flagged confusing open-vs-click outcomes and low trust in Kajabi analytics. Short tests also favor people who open early — easy to hide behind a confident “winner” label.

    Led to Decision 03 — safe defaults plus planned in-product tips (what the time window measured; don’t overclaim). See The experience · Test options.

  4. 04 · Early MVP brief → strategy / competitive review

    Scope grew from subject-only to a fuller test

    The first MVP brief limited v1 to subject + preheader, two versions, and manually sending the winner to everyone else. Strategy and the competitive review pushed further: creators already paid elsewhere to test body/preview, and subject-only wouldn’t close the gap people expected.

    Led to Decision 02 — v1 can vary subject, preview, or body; holdout + backup stay; auto-scheduling the winner moves to a later phase.

  5. 05 · Eng constraints · strategy timing

    The learning loop had to ship before an editor rebuild

    The email editor was old and fragile, and a redesign looked like a multi-quarter project. Waiting on that rebuild would have left the 84%-expected A/B gap open longer.

    Led to Decision 04 — ship A/B on the compose surface we already had; scope the fuller editor redesign as a separate track.

Those findings set the product direction before polished screens — then the experience had to show that honesty in the UI, not only in the doc.

How v1 scope changed

First brief: subject + preheader only; creator manually sends the winner to the rest of the list.
What shipped (v1 → v2): subject, preview, or body; creators set the win rule, duration, and backup; clear compare, no overclaim — then auto-schedule the winner to the rest of the list so creators don’t babysit the report.

Competitive research

I owned the competitive synthesis — tearing down A/B across Braze, Beehiiv, ConvertKit, HubSpot, Mailchimp, Klaviyo, ActiveCampaign, and Unbounce before locking the PRD. Three implications shaped the product bets:

  • Don’t gate on list size — most “serious” A/B assumes big audiences; educate on what a short window can prove instead (Decision 03).
  • Subject-only isn’t enough — deeper tools put preview/body behind paid tiers (~$187/mo elsewhere); ship subject, preview, or body in v1 at no add-on cost (Decision 02).
  • Honesty over a confident wrong answer — Braze shows when results aren’t decisive and still lets you proceed; creators set metric + fallback (Decision 01).

Decisions

Four product calls that answer the problem above — without copying how big email tools do A/B.

01Model

Creators define winning. No fake significance.

Rejected Auto-pick by statistical significance · fixed default metric

Call: Creators set the winning metric (open or click), test duration, and fallback before the test starts. After the window, the higher metric wins and sends to the holdout. If A and B tie, the pre-chosen fallback becomes the winner automatically — same winner UI, no separate “inconclusive” badge.

Why: Same pattern as the Braze teardown: honesty over a confident wrong answer. AI drafts stay a starting point for variants, not a recommended winner. Insights · 02 cover the small-list constraints.

From Insights · 02

02Wedge

Subject, preview, or body in v1. No add-on tax.

Rejected Subject-line-only v1 (ConvertKit / Beehiiv-shaped)

Call: v1 lets creators vary subject, preview text, or body, plus duration, as standard features. Side-by-side editing keeps body variants understandable.

Why: Creators asked for a full learning loop, not subject-only table stakes. They already pay ~$187/mo elsewhere for that depth. Shipping flexibility at no add-on cost closes the parity gap the survey flagged. Scope change: the first MVP brief limited v1 to subject + preheader; strategy risks and the teardown pulled body into the shipped design direction (see Insights · 01 & 04).

From Insights · 01 · 04

03Defaults

Defaults that can’t accidentally become “not a test.”

Rejected No minimums (common in competitor products)

Call: Default split 25% / 25% / 50% holdout, with rounding and guards for tiny recipient sets so creators can’t ship 0/0/100 by accident. Planned in-product copy: short windows only reflect early openers; explain what the window measured — don’t overclaim (see Decision 01). Ties are handled quietly: equal win-metric → the fallback chosen in settings becomes the winner (same winner UI).

Why: Small lists need a real test by default. Ambiguous open-vs-click outcomes and low analytics trust were explicit strategy risks. Explainers belong next to duration and results — not only in a help article.

From Insights · 03

04Scope

Ship the learning loop on the editor we had — not the redesign we wanted.

Scoped separately Email editor redesign (newsletter / blog / writing surfaces) · Classic Editor · Automated emails

Call: v1 adds A/B to the existing one-off email experience on the modern React editor. The fuller editor redesign — and Classic / automated email coverage — wait as their own track.

The tension: Eng pushed back on touching the email editor — outdated and fragile across Rails vs React, a rewrite looked like a multi-quarter sink. I wanted a redesigned editor with more flexible editing and preview so variants could be first-class; that craft bar was right, but pairing a platform rebuild with a net-new learning product would have delayed the 84%-expected gap.

Why this was the right bet: We separated proving the learning model from rebuilding the writing platform. Email A/B shipped on the compose surface we had. The editor redesign was scoped as a separate project so it could be done well — more fluid editing and preview, and reusable beyond email for newsletter, blog, and other text-writing needs across the product. That kept eng risk contained, got creators a trustworthy A/B loop sooner, and still let me define reusable patterns (variants, win metric + fallback, comparative results) that sibling teams used for landing-page A/B.

From Insights · 05

The experience

A learning loop: variants → options → test → winner

Shipped UX · v1–v2, pivot One-off email A/B through schedule-send-to-winner; click report / win-by-link from user interviews — screens may be prototype unless noted

Before: one email, one send. No way to compare subject, preview, or body inside Kajabi before committing the whole list.

“I don’t need a stats lecture — I need to know if this subject actually got more people to open.”

— Creator interview, Messaging & CRM research

Side-by-side editing keeps subject, preview, and body differences understandable. Creators set the win rule and fallback (Decision 01); the system runs the test and shows what worked — without overclaiming.

01 · Entry: start new, or convert a broadcast

I want to create an A/B test from the start — or convert my email broadcast draft into an email A/B test.

Why: creators already writing a one-off broadcast shouldn’t abandon it to test. I owned this entry path: convert the draft into an A/B (or start A/B fresh), then write version A and a B variation. Side-by-side editing keeps subject, preview, and body differences understandable.

02 · Test options: creators define winning

I want to decide how a winner is chosen — and which version wins if A and B tie.

Why: four controls decide how the test runs. Creators also choose when the first test emails go out.

A/B test distribution — set the size of your test group: 25% / 25% / 50% holdout (default) or 10% / 10% / 90%.

Winning metric — open rate or click rate (click only if the email has links); this determines the version sent to remaining recipients.

Test duration — 1–10 hours after the last test email is sent.

Fallback version — Version A or B applied as the winner if A and B tie on the winning metric. Chosen in settings before the test; no separate inconclusive indicator — results show equal metrics and the fallback marked as winner.

Trust copy (planned next to duration / results): short windows mostly reflect early openers; explain what the window measured — don’t overclaim (Decision 01); a tie quietly uses the fallback you already chose.

03 · Results while the test runs

I want to see how my A/B test performed.

Why: while the test is in progress, creators compare A and B side-by-side (opens, clicks, and email previews). The UI stays comparative — planned helper text that early open rate can shift as the window fills (see Decision 01).

Scroll the image, or click to view it larger.

04 · Winner sent to the rest

I want to see how my winning variant performed.

Why: after the window, the winning variant goes to the remaining contacts — including when A and B tied and the pre-chosen fallback was applied as winner (equal metrics; fallback shown as winner, no “inconclusive” label). The report separates the original A/B sample from the winner send so creators can see both what the test measured and how the winner performed at full reach.

Scroll the image, or click to view it larger.

05 · Click report & win by link Shipped

I want to see which links got clicks — and pick a winner from a specific CTA, not only total clicks.

Why: total clicks hide which CTA drove action. The pivot added a clearer click report and let creators win by a specific link (e.g. “Buy Now”) when that was the goal of the test.

Outcome

One-off email A/B shipped through v2. Interviews drove a pivot — click report and win-by-specific-link. The A/B pattern was reused for landing-page A/B.

  • Shipped: subject, preview, or body tests; auto-send the winner; then click-level wins after the pivot. Strategy approved; a dedicated PM unlocked delivery.
  • In progress separately: sequence email A/B (different product).
  • Systems: same compare / win / fallback model on landing pages.

Reused on landing pages

I defined the A/B pattern — variants, how a winner is chosen (and a backup on a tie), and clear side-by-side results. Other teams reused it for landing page A/B so they didn’t have to invent the comparison pattern again.

Landing page A/B — same set up, compare, and apply pattern as email

2024 company goals · How this helped

  • Catch up & keep creators (parity & retention): fund a top expected email gap so people can get depth inside Kajabi instead of paying ~$187/mo elsewhere.
  • Brand & revenue (GMV): honest A/B for small lists as a way to learn what earns opens and clicks — and better conversions — without “export to Mailchimp to learn.”

Metrics we proposed after ship

Not measured yet — proposed in the strategy (baselines from Messaging & CRM research):

  • % of creators using Kajabi email; revenue tied to email
  • Open/click lift on A/B’d vs non-tested emails
  • High-revenue creators unhappy with email (baseline 41%)
  • Spend on outside email tools (baseline ~$187/mo)
  • Creators gaining at least 1 contact / 30 days (baseline 23%)

Reflection

What worked: Studying competitors before the plan locked — cutting scope with engineering when the editor rewrite stalled — and pivoting when interviews asked for a click report and win-by-link. Seeing ConvertKit’s subject-only plans next to Braze’s honest “we’re not sure yet” results made the gap clear. Shipping A/B on the compose screen we already had got the learning loop out without rebuilding the whole editor; listening after ship kept the roadmap honest.

What I’d change: Put results explainers in the first prototype, not the backlog. Short test windows can make open rates look worse than they are — that should have been clear in the UI from day one. Pull support-ticket language earlier; churn interviews named the gap, tickets named the words people use.

Tradeoff I still sit with: putting off a fuller editor redesign (and Classic email coverage) so one-off A/B could ship through v2 and the click-report pivot. Right call for risk and speed — other teams still reused the patterns on landing-page A/B — and sequence email A/B is now a separate project where learning can build over time. Side-by-side edit and preview never got the polish I originally wanted.

Takeaway: A/B is a learning tool first (Decision 01). “Which version wins?” is the wrong default for an 800-person list. “Which metric matters, what happens on a tie, and what did this window actually measure?” is the question worth defending.

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