Transactional emails are functional, but they are also the highest-engagement email type in your stack. Designed well, they drive product engagement, upsells, and retention.
Lead with the action. The first thing the reader sees should be the answer to "did the thing I expected happen?" Order shipped: show the order summary. Password reset: show the button.
One primary action per email. Multiple CTAs split attention and drop conversion. If you need a secondary, make it a text link, not a button.
Personalize beyond first name. Order numbers, product names, dates, recipient-specific details. They prove the email is for the specific person, not a blast.
Mobile first. 70% of opens are on mobile. Test on a phone before shipping.
Plain-text fallback. Every transactional email should have a plain-text alternative. Mailbox providers favor multipart/alternative messages.
Keep the brand light. A subtle header and footer is enough. Heavy branding distracts from the action.