My account dashboard

Log in
Start With Free Plan
Grow your business, not your expenses

Turn curious visitors into devoted fans and drive more sales – no cost to get started!

Start free

Sender > Features > Email A/B Testing

A/B test your way to success with experiments

Email A/B testing sends multiple email variants to separate audience segments and automatically delivers the top-performing version to the remaining list. Marketers and ecommerce teams use Sender’s Experiments feature to test subject lines, content, and send times – replacing campaign guesswork with real data from their own subscribers.

Start With Free Plan

No Credit Card Required. Cancel Anytime.

Join over 180,000 companies using Sender

Optimize email conversions using A/B testing strategies

29%

improvement in conversion rates is typically achieved by A/B testing subject lines.

(Growbo, 2025)

37%

higher email marketing ROI is achieved by brands that A/B test every email.

(Litmus, 2019)

Up to 25%

higher open rates are possible when testing the optimal sending time compared to sending at random times.

(Optimazely, 2024)

What to test?

Subject lines

Test whether your audience wants you to get to the point or spell everything out in subject lines. Find out if emojis make you relatable or unprofessional, and whether "act now!" urgency drives clicks or just drives people crazy.

Email content

Test if your readers want a simple, single-column layout or prefer multiple columns with more to explore. Experiment to find the CTA that practically clicks itself, and figure out whether your audience prefers pretty pictures or text.

Time & frequency

Discover when your audience actually wants to hear from you. Find your sweet spot between staying top-of-mind and becoming that sender who won't take a hint, and make sure your emails land when people are ready to read them.

Sender information

Test whether your subscribers open more from a personal name – "Sarah from Marketing" – or your brand name. Find out which sending address gets the best response (hint: it's rarely noreply@) and whether a reply-enabled address builds more trust.

Start With Free Plan

No Credit Card Required. Cancel Anytime.

Statistical significance
tracking

Numbers don't lie, but they can be confusing. Sender's statistical significance calculator tells you precisely when your test has collected enough data to declare a reliable winner – no premature decisions.

Real-time results
dashboard

Monitor A/B test results as your campaign sends. See which version is winning before the test closes and make decisions based on live performance data – not final summaries.

Integration
capabilities

Pull behavioral targeting data from your CRM, ecommerce store or other platform, apply segmentation and personalization, and run smarter email marketing test campaigns.

Split test your automated workflows

Go beyond subject line testing and experiment with entirely different workflow logic. Add SMS follow-ups on one path versus email-only on another, or test varying time delays to find the absolute perfect pacing for your drip sequences.

Optimize the automated stages that drive the highest ROI. Email split test abandoned cart reminders, and post-purchase sequences to continuously capture missed revenue on autopilot.

Sender's email A/B testing tools run split testing perpetually in the background. New subscribers are randomly and evenly distributed into your test branches, accumulating data and scaling your conversions 24/7.

How does email A/B testing work?

Step 1: Create test variations.

Create test variations – test subject lines, content, send times, and CTAs.

Step 2: Send and track results.

Send and track results – Send to different test segments and see how open rates, click rates, and engagement change.

Step 3: Winner email is sent out to everyone else.

Send out the winner – Deliver the best-performing version to the campaign list or automation sequence.

Need full setup details?
Follow our step-by-step experiment setup.

Start With Free Plan

No Credit Card Required. Cancel Anytime.

Integration with tools you already use

Sender's email marketing software instantly integrates with landing content management systems, CRMs, and ecommerce platforms, including WordPress, PrestaShop, WooCommerce, Zapier, and more.

WordPress

WooCommerce

PrestaShop

Zapier

Shopify

Jumpseller

MCP Server

Check out all Integrations

Frequently Asked Questions

What is email A/B testing?

Email A/B testing is the practice of sending two or more email variants to separate portions of an audience to determine which version performs better. The winning variant – based on open rate or click rate – is then automatically delivered to the rest of the list. It is the standard method for improving subject lines, content, send times, and sender names through real subscriber behavior rather than assumptions.

What should I test first in email A/B testing?

Subject lines are the most effective starting point because they directly determine open rates. Once subject line performance is stable, move to sender names, then email content and call-to-action placement. Test one element per experiment – changing multiple variables at once makes it impossible to identify which change drove the result.

Can I A/B test automated emails, not just campaigns?

Yes, inside Sender's automation builder, a Split block divides workflow traffic between two email variants – subject lines, content, or offers – and tracks which path drives better engagement. This applies to welcome series, abandoned cart flows, and any other automated sequence.