Your transactional email subject line has one job: set the right expectation so the user instantly trusts the message.
This isn't the place for cleverness. For password resets, magic links, invoices, and “something changed” alerts, clarity beats curiosity every time.
A good default pattern is: [Action] for [Product].
What makes a transactional subject line “good”
- It matches the user's intent: they requested a reset, they started checkout, they expect a receipt.
- It reduces cognitive load: no riddles, no hype, no ambiguity.
- It signals legitimacy: product name + specific action + consistent tone.
Transactional subject lines should almost never include: emojis, excessive punctuation, urgency spam (e.g. “ACT NOW!!!”). That's marketing behavior — and it can hurt trust.
7 rules that keep you out of trouble
- Say what the email is. If it's a receipt, say “Receipt”.
- Include your product name (or the domain) for recognition.
- Keep it short: aim for ~35–55 characters.
- Don't promise discounts in transactional flows unless it's truly a marketing email.
- Avoid fake urgency. Security emails can be urgent, but don't sound like a spammer.
- Be consistent across the same event (reset emails shouldn't vary wildly).
- Write for scanning. Put the action first, details second.
25 subject line examples (by email type)
Password reset
- Reset your password for React Emails Pro
- Password reset request (React Emails Pro)
- Reset link for your React Emails Pro account
- Your password reset link (expires soon)
Magic link / sign-in
- Your sign-in link for React Emails Pro
- Sign in to React Emails Pro
- Your one-time login link
- Login link requested for your account
Email verification
- Verify your email for React Emails Pro
- Confirm your email address
- Finish setting up your account
- Verify your email to get started
Receipts & invoices
- Receipt: React Emails Pro (#12345)
- Payment receipt for your subscription
- Invoice available: React Emails Pro
- Your invoice for February
Account changes (security)
- Your password was changed
- New sign-in to your account
- Security alert: new device sign-in
- Email address updated
Onboarding nudges (still transactional-ish)
- Welcome to React Emails Pro — here's what to do next
- Set up your first template
- Your account is ready — publish in 5 minutes
- Quick setup checklist
“Bad” subject lines (and the safer rewrite)
- Bad: IMPORTANT — ACTION REQUIRED!!!
Better: Reset your password for React Emails Pro - Bad: Your account has been compromised
Better: Security alert: new sign-in to your account - Bad: Congratulations — you're selected!
Better: Verify your email to finish setup - Bad: Don't miss this
Better: Receipt: React Emails Pro (#12345)
If you're unsure whether a subject line is transactional or marketing, ask this: would the email still be sent if the user opted out of marketing?If yes, keep it boring and literal.
Implementation tip: keep subjects as constants
Treat subject lines like product UI: version them, test them, and avoid random variation.
A simple pattern is to define subject builders alongside your templates, e.g. subject.resetPassword() orsubject.receipt(orderId), so the copy stays consistent.
Clarity scales. Cleverness breaks.