Donezo InboxFree email subject line generator
Paste your email, or describe it in a sentence, and get five subject lines to choose from. It is free, needs no sign-in and does not store what you type. Pick one that is true to the email, not just the catchiest one.
Suggest subject lines
What makes a good subject line?
- It says what the email is. The reader should know from the subject alone whether it is for them and what to do.
- It is short enough to read on a phone, usually under about 50 characters.
- It matches the email. A subject that promises more than the body delivers is worse than a dull one.
- Time-sensitive only when it is. Use that style when the email really has a deadline.
What happens to what you type?
- It is sent to Cloudflare Workers AI, an AI model that writes the answer, and the answer comes back to this page. Nothing else is done with it.
- Donezo Inbox does not store what you type or what comes back, does not write either to its logs, and does not keep a cache of them. A request is counted, and the count is tied to a scrambled version of your network address, not to the address.
- This tool does not read your mailbox and does not need you to sign in. Paste only what you are comfortable sending to an AI service.
- The page loads the same analytics script as the rest of this site. It records page views, never the text in these boxes.
What are the limits?
- A few tries an hour for each visitor, and a daily limit shared by everyone. When the day's limit is used up the tool says so and tries again the next day.
- Short inputs (about 2,000 characters in all) and short answers. For long threads, use the app.
- The answer is written by an AI model and can be wrong or flat. It is told not to invent names, dates, prices or attachments and to leave a [placeholder] instead, but you must read it and check every detail before you send it.
How is this different from Donezo Inbox?
This tool suggests subjects from one email. Donezo Inbox is the Gmail client around it, with the assistant that labels what needs an answer and drafts replies in your tone. Pro is $29/year (about $2.42 a month), one yearly plan with no monthly option. The email client is free for one inbox.
Donezo works with Gmail and Google Workspace only. It has no Outlook or IMAP support, no shared inbox or assignment, no meeting notes and no scheduling links.
Questions
Is this subject line generator free?
Yes. No sign-in, a few tries an hour for each visitor, and a daily limit shared by everyone.
Does it test which subject gets more opens?
No. It suggests wording. It does not measure opens, and Donezo Inbox makes no claim about which style performs better.
How long are the subject lines?
Each is kept under 90 characters and the model is asked for under 70, so they read well in an inbox list.
Do I need to paste the whole email?
No. A sentence describing it is enough.
Want this inside your inbox?
Pro is $29/year (about $2.42 a month), one yearly plan with no monthly option. The email client is free for one inbox. It writes in your own tone, inside Gmail.
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