When it comes to email marketing, A/B testing isn’t optional—it’s essential. It’s the only reliable way to know whether your email strategies are actually working or if you’re just guessing. While most brands focus on testing campaign emails, one of the highest-leverage areas you can optimise is your automated flow emails—because these are always firing to customers, day in and day out.

If your flows aren’t optimised, you could be leaving money on the table every single day.

Why A/B Test Automated Flows?

Flows—like abandoned cart sequences, welcome series, and post-purchase emails—run automatically in the background. They’re triggered by customer actions, meaning they can capture interest at critical decision-making moments. Since they operate continuously, even small performance improvements can translate into massive revenue gains over time.

No two audiences behave the same way—and what works for one brand may fall flat for another. That’s why split testing is one of the most valuable tools you have for optimizing your flows. By testing different variations of timing, offers, and content, you can identify what resonates most with your audience and continually improve performance.

By testing, you ensure these critical touchpoints are:

Maximising conversions.
Delivering the right message at the right time.
Removing friction from the buying process.

A/B Testing Flow Emails infographic lists key elements to test: graphic vs. text emails, flow time delays, content length, subject lines, and categories.

High-Leverage Flow A/B Tests to Run

The Welcome Offer (Percentage vs. Dollar Discount)

Discount structure has a major psychological impact:

$10 Off feels more compelling for higher-ticket products.
10% Off can feel more attractive for lower-priced items.
Benefit of testing: You’ll identify which format resonates with your audience and maximizes conversions without unnecessarily cutting into margins.

Flow Time Delays

Why test: Timing can make or break a conversion. Sending too early may catch someone still browsing; too late, and they may have already purchased elsewhere.
Example test for abandoned carts:
- Version A: First reminder 30–60 minutes after abandonment.
- Version B: First reminder 4 hours later.
Follow-up delay tests: Should you wait 12 hours between emails? 24 hours? 48? Each audience behaves differently.
Goal: Identify the “sweet spot” where urgency meets convenience.

Time Delays Between Emails (1 Day vs. 2 Days)

Timing matters in email marketing. Sending emails one day apart keeps your brand top-of-mind and works best for impulse-driven purchases where customers are primed to buy quickly. On the other hand, two-day delays give customers breathing room and may be better for higher-consideration items or when you want to avoid list fatigue.
Benefit of testing: You’ll learn how quickly your audience prefers to hear from you, which can reduce unsubscribes while maximizing conversions.

Long-Form vs Short-Form Content

Why test: Some situations call for quick, punchy emails to trigger impulse buys. Others require more detail to overcome objections.
Example test:
- Short-form: 2–3 sentences + CTA.
- Long-form: Detailed benefits, FAQ-style objection handling, testimonials.
Best flows to test: Abandoned carts, browse abandonment, win-back sequences.

What Products Are Featured in Emails

Your welcome flow should highlight products that are most likely to convert new subscribers. Split testing which products you feature will reveal which items customers tend to buy first.
Benefit of testing: This data helps you identify natural entry-point products that pull people into your ecosystem. You can then optimize your flow to feature those products more prominently, while using other emails to upsell or cross-sell later.

Subject Lines (SLs) and Preview Texts (PTs)

Why test: Your subject line and preview text decide whether your email gets opened.
Example tests:
- Including the discount amount vs not mentioning it.
- Using emojis vs none.
- All caps vs sentence case.
- Adding “…” for curiosity vs leaving it out.
Goal: Boost open rates without sacrificing click-through or conversion rates.

Test	Example 1	Example 2
Discount vs. No Discount	“Your 10% Off is Waiting!”	“Forgot Something?”
Title Case vs. sentence case	“Complete Your Order Today”	“Complete your order today”
Urgency vs. Curiosity	“Hurry! Cart Expires Soon”	“Still thinking it over?”
With vs. Without product mention	“Still want your Red Midi Dress?”	“Don’t Miss Out!”

Categories vs Individual Products

Why test: Some customers prefer browsing categories (e.g., “Shop Our Winter Collection”), while others want to see specific products. Split testing links allows you to see whether subscribers are more likely to convert when given a direct path to one hero product or when exploring multiple options. You’ll discover whether clarity or choice drives more revenue for your audience.
Example test:
- Version A: Category landing page with multiple options.
- Version B: Direct product page for one highlighted item.
Goal: Find which format drives more add-to-cart and purchase actions.

Combining Graphic and Text-Based Elements

Why test: You don’t always need to choose one style—sometimes a hybrid works best.
Example: A hero product image + short, conversational copy underneath.
Goal: Determine if a blend of visual appeal and personal tone improves engagement.

Testing Educational Angles in Campaigns (Then Adding Winners to Your Flow)

Educational content builds trust and overcomes objections. By testing different informational angles in your campaigns—such as FAQs, tutorials, or myth-busting emails—you can see which ones drive the most engagement and revenue.
Example: A supplement brand tests an FAQ email answering “How long does it take to see results?” If it performs exceptionally well, they can add a discount code to that email and plug it directly into their welcome flow, replacing the lowest-performing email.
Benefit of testing: Your welcome flow becomes a living, optimized system where only the highest-performing content makes the cut, ensuring every email works hard to convert.

Keys to Running Effective Flow A/B Tests

Test one element at a time so you know exactly what caused the result.
Ensure your audience size is big enough for statistically significant results. Small sample sizes = unreliable conclusions.
Run the test long enough to account for natural behaviour variations.
Measure the right metrics: For flows, conversions and revenue matter more than just open rates.

Final Takeaway

Flows are your always-on sales team. By A/B testing them—especially abandoned cart timing, design style, and content length—you can make sure every automated touchpoint works as hard as possible.

Even small improvements in flows will compound into significant revenue growth over time, making A/B testing not just valuable—but essential.

✅ Wrap-up: Keep Testing & Improving

Flows are your always-on sales team. By A/B testing them—especially abandoned cart timing, design style, and content length—you can make sure every automated touchpoint works as hard as possible.