Can I test different parts of the message in one A/B test?

No, in the editor you can only test subject lines.

Legacy editor

When creating an A/B test you must define one type of a test to be sent out; combinations between different test types are not possible. You can browse between the test types, but only the enabled one will be sent out.

If you’re unsure what type you’ve enabled, don’t worry. That’s what our Summary page is for. Before you send out the A/B test, we will present you with a summary of your A/B test and you can always jump a step back.