[NTTP]

Email Subject Line Writer

Describe what your email is about and get several specific, non-spammy subject line options to choose from.

The key content or ask. Include the specific details, a date, a number, a name, so the subject lines have something real to point at.

Optional

Optional. e.g. get a fast reply, stand out in a busy inbox, sound low key and not salesy.

Free to try, no sign-up needed

Your text isn't stored. It's sent to Anthropic to generate your result, then discarded. Privacy

Prefer to write it yourself? Use the free prompt.

New to this? Read the guide.

What it produces

Real output from this tool, not a mock-up.

What went in

What is the email about
Telling existing customers that our pricing is going up in January, about 8%, first increase in three years. Anyone on an annual plan keeps their current rate until renewal. We are adding two features they have asked for.
What kind of email
Update
Goal for this subject line
Get it opened and read, not deleted. Honest, not sneaky.

What came back

  • Pricing update: 8% increase starting January (first in three years)
  • Your rate is changing in January, here's what's new too
  • Heads up: prices go up 8% in January, annual plans locked in until renewal
  • January price change: what it means for your account
  • Before January: your new rate, and two features you asked for
  • An 8% price increase is coming, here's how to keep your current rate
  • Price change ahead: details on the increase and two new features
  • Your account: January pricing update plus what stays the same

When to use it

Use this when the email is written and the subject line is the last thing standing between it and being opened. You get several options taking different angles, built from what the email actually says rather than from a template.

Common questions

How long should a subject line be?
Short enough to survive a phone, which means roughly 40 to 50 characters before it truncates. The options come back in a usable range, and the specific ones tend to outperform the clever ones.
Will they be spammy?
They are written to avoid it: no all caps, no fake urgency, no "quick question" on an email that is not one. A subject line that oversells gets the open and loses the trust, and with genuinely bad ones it gets you filtered.
Why does the email type matter?
Because a sales subject line and an internal update are judged differently. An internal note can be flat and factual; a sales email has to earn attention without overpromising. The type sets which trade-off applies.
Is it free?
You can run it three times a day with no account. Signing in gives you renewing monthly credits, and this tool costs one credit per run with the one-click refinements included.