Run an A/B test on your campaign
Test two subject lines in Mailsoftly. Set up your variants, choose a test group and wait time, launch the test, and read the results to find the winner.
An A/B test lets you compare two subject lines and send the stronger one to the rest of your list. This guide shows you how to set one up and read the outcome.
You will start from a campaign, define your two subjects, launch the test, watch it run, and see which version won.
Open a campaign to test
Open Campaigns and choose the draft you want to test. This is the campaign that will carry your two subject lines, so make sure the email itself is ready and the recipient list is large enough to split into a test group and a remainder.
A/B subject testing needs a From address at your own verified domain and a list with at least 20 recipients. If the option is greyed out, check the sender and the list size first.
Set up your variants
Press Review and Send, then choose A/B Test Subject to open A/B Test Your Subject Line. Mailsoftly explains the idea: it sends your current subject to one half of a small test group and a second subject to the other half, and after the wait period the subject with more opens goes out to everyone else automatically.
Fill in the two fields and settings:
- Subject A (current) is already filled with your draft subject. Subject B is where you write an alternative subject line, and a wand button beside each field can suggest options if you are stuck.
- Test group sets what share of the list receives the two subjects, and Decide after sets how long to wait before a winner is chosen.
The note at the bottom explains that the subject with more unique opens wins, that opens from bots and scanners are excluded, and that a tie goes to Subject A. When both subjects are written, press Start A/B Test.
Change one thing at a time and keep the two subjects genuinely different. A/B tests are most reliable on a large enough list, so treat close results on a small audience with caution.
Launch and watch it run
Once the test is live, Mailsoftly sends the two subjects to your test group and tracks how each performs. A running badge appears and tells you roughly when the winner goes to the rest of the list.
You can let it finish on its own, or use Pick Winner Now to send the leading subject to everyone right away. Stop Test ends the run without choosing a winner, in which case only the test group has received the campaign.
Read the results and find the winner
When the test decides, the Campaign Details tab shows the outcome. A line confirms the test finished and which subject won and was sent to the rest of the list, and each subject shows how many opens it earned out of the number sent, with a percentage. The winning subject is marked with a trophy and a Winner label, and a matching pill appears in the campaign header.
Now you have real evidence behind your choice, and each test teaches you a little more about what your audience responds to.
Open your A/B test results in Mailsoftly
Ready to try it in your own account?
Free to start with your Google Workspace or Microsoft 365 account. No credit card required.
