There is a common but very important saying in digital marketing.
What worked yesterday will not always work tomorrow.
Attention spans shift, inboxes get louder and whatnot You Remember that a great subject line means nothing if your audience doesn’t agree. That’s why A/B tests are not just “nice to have”, they are non-negotiable.
Smart entrepreneurs don’t rely on hunches. They test everything: subject lines, CTAs, send times, and even who the email appears to be from.
Why? Because small wins add up. A 5% increase in open rates here, a 10% increase in clicks there—suddenly that same email list is generating 30% more revenue without spending an extra dollar on growth.
In this article I will explain why you should do this always Run at least one test, learn what powerful elements are worth experimenting with, and how to do it without wasting time or getting lost in the data.
Whether you’re scaling your eCommerce brand or optimizing a lean SaaS funnel, these tactics will help you get more out of your existing audience.
Do you have little time? Here are the key takeaways
- A/B testing is non-negotiable if you want to increase opens, clicks, and conversions without growing your list.
- Always test high impact items like subject lines, CTAs, send times and sender names. Small optimizations can lead to big results.
- Only test one variable at a time This way you know what actually drives performance.
- The right platform makes it easy. Omnisend helps you automate, segment, and A/B test faster without a cumbersome tech stack.
Why A/B testing is no longer optional
Most founders are obsessed with growth, but often the real opportunity is right in front of them: conversion optimization.
If you’ve built even a small email list, you can use A/B testing to achieve consistent profits without expanding your list or budget.
The statistics behind email optimization
Omnisend’s recent analysis of billions of emails shows Average open rates increased from 22.9% in 2022 to 25.1% in 2023 among its merchants, and click-through rates increased from 1.2% to 1.5%, all due to better testing and segmentation.
Automated emails delivered even better results. They had that 52% higher open rates, 332% higher click ratesand a breathtaking one 2,361% better conversion rate than normal campaigns.
This means that triggered flows like welcome messages and abandoned cart emails are much more efficient at converting opens into sales, but only if they are optimized through AB testing.
When small elevators assemble
Even a 5% increase in opens or a 10% increase in clicks doesn’t sound revolutionary until it passes through your entire funnel. Omnisend customers When testing the number of abandoned carts, additional monthly sales increases of around $5,000 were achievedwith small but steady increases in open and click rates in just a few months of testing.
Better subject lines, smarter CTA texts, optimized timing – every improvement multiplies.
Real readers surpass assumptions
A shock 43% of people decide to open an email based on the subject line alone. And bad copy? Approximately 69% of users mark an email as junk based on the subject alone, which impacts both engagement and future deliverability.
Omnisend also confirms that personalized subject lines increase open rates by up to 26%, especially when combined with segmentation and automation.
What you should test
A/B testing isn’t just about finding “better” subject lines or button colors, it’s also about understanding your audience deeply so you can deliver the right message to them at the right time in the right way.
Here are the high-impact elements every founder should test regularly:
Subject lines
Goal: Improve open rates
Why it matters: If your email doesn’t open, the content in it doesn’t matter.
What to test:
- Curiosity vs. Clarity (“You won’t believe this…” vs. “Your 15% discount ends today”)
- Personalization (first name, location or purchasing behavior)
- Emojis vs. plain text
- Urgency and scarcity language
CTAs (call to action)
Goal: Increase click-through rates
Why it matters: Here, openings become actions such as clicks, purchases and registrations.
What to test:
- Button Copy: Shop Now vs. Request a Quote
- Button vs. hyperlink text
- CTA placement: top, middle or bottom
- Number of CTAs per email (single vs. multiple offers)
Broadcast time and frequency
Goal: Maximize visibility and engagement
Why it matters: Even the best content will be ignored if sent at the wrong time.
What to test:
- Weekdays vs. weekends
- Early morning vs. afternoon vs. evening
- Time zone segmentation
- Frequency: daily, weekly, biweekly
Sender name and preheader text
Goal: Increase trust and curiosity
Why it matters: The “From” field and preheader often have a greater impact on opens than the subject line.
What to test:
- Sender Name: Brand vs. Personal (“Acme” vs. “Sarah from Acme”)
- Preheader style: benefit-oriented, curious or educational
- Pairings: How subject + preheader work together
Audience segments
Goal: Increase relevance and conversions
Why it matters: Blanket emails will not convert. Micro-targeted specimens do this.
What to test:
- First-time customers vs. loyal customers
- Spend a lot of money compared to inactive users
- Affinity to the product category (e.g. men’s or women’s items)
- Cart abandoners vs. browsers
Why a test should always be run
Testing is not a one-time tactic; it is a system. The best-performing brands don’t just test when they get stuck; They make testing part of their daily process. Here’s why this mindset is important and how you can incorporate it into your workflow.
Your audience is constantly changing
People don’t always open, click, or buy in the same way. Preferences change based on seasonality, inbox overload, competitive offers, and even economic conditions. What came to a standstill last month could fail today. A/B testing helps you stay in tune with your audience.
Example: A subject line that works in July (“Stay cool with this 1-day offer”) might fail in October when priorities have shifted. Testing gives you real-time insight into the actual response.
Test small, win big
Testing doesn’t require large budgets or development-intensive funnels. You can get statistically relevant results with:
- An email list with just 1,000 people and a 50/50 split
- Only test one variable (e.g. subject line) per send
- Run the test until at least 25-30% of your total list is activated
Small optimizations lead to big results.
Tests create intelligence, not just results
Each test gives you data you can reuse in emails, ads, landing pages, and beyond.
Are you learning that “curiosity-based subject lines” perform better than useful subject lines for your audience? That applies everywhere. This is how small brands move fast and punch above their weight.
How to run a smart A/B test without wasting time
A/B testing only works when set up correctly. Otherwise you are just comparing guesses. Here’s a simple, repeatable framework you should follow every time:
1. Start with a hypothesis
Don’t test randomly. Know what you want to learn.
Bad: “Let’s try a red button.”
Good: “We believe a benefit-focused CTA (“Get My Discount”) will increase clicks by 10% compared to a general CTA (“Learn More”).”
2. Test one variable at a time
To find out what caused the result, isolate a single change:
✔ Subject line
✔ CTA copy
✔ Send time
✘ Subject line, CTA, And Design (You won’t know what moved the needle)
3. Choose the right metric
Your test goal should match what you’re changing:
- Test subject line? → Measure open rate
- Test CTA? → Measure click rate
- Test landing page copy? → Measure conversion rate
4. Send a sufficiently large sample
Avoid false alarms. Most platforms (like Omnisend) recommend testing with at least 1,000 recipients per version to get meaningful results.
If your list is small, consider a 20/20/60 split:
20% see version A, 20% see version B, and the winning version goes to the remaining 60%.
5. Document and apply what you have learned
What worked? What not? Why?
Track every test and every result. Over time, this will become yours Competitive advantagea private library of what your audience actually responds to.
Last word
You don’t have to overhaul your entire marketing strategy to get better results. You just need to test one thing consistently and with intention.
Whether it’s your subject line, your CTA, or your timing, every little experiment gets you closer to what actually works for your audience.
That’s where Omnisend makes a difference. Designed for fast-moving eCommerce brands, it allows you to automate smarter operations, segment with ease, and optimize every shipment without having to juggle multiple tools or workflows.
Foundr readers get 50% off their first three months with code FOUNDR50.
Start testing smarter. Start converting more. Secure your discount now.
