Best cold email subject line generator tools compared.

20 Best Email Subject Line Generator Tools

Email Subject Line Generator tools are a modern trend used by cold emailers to reach their potential clients. In the earlier days of the web, people used to hire virtual assistants who charge 6 to 10 cents per email, but with the advancement of AI - we have great subject line generators, which have proven to get great response rates.

1. Free AI Subject Line Generator by Encharge.io

Encharge.io is a primary tool used to send behavioral emails like Crewcharge. However, they are kind enough to release a bunch of free tools around marketing to help sales and marketing individuals send better emails.

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Features of Encharge.io's ai subject line generator.

Pricing: free

Login required: No

Captcha Required: No, tried 20+ consecutive hits.

Number of subject lines per hit: 7

AI Model: GPT-3 AI

Why we love Encharge.io's subject line tool:

  • No login is required to use the tool.

  • Powered by GPT-3 AI.

What we dislike:

  • Since the tool is powered by GPT3 AI, sometimes it's a hit or miss on some of the suggestions that are completely unrelated to your campaign.

2. Warmer.ai Intro Line Generator

Introlines are just as important as subject lines. Although it doesn't directly create subject lines, we think it's really cool that's it's able to create lines that people are unable to distinguish from real people.

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Features of Warmer.ai

Pricing: 10 free lines (no free forever plan)

Login Required: Yes

Rate limited: Yes - 10 per lifetime.

Number of Subject Lines Per Hit: 1

AI Model: GPT-3 AI

What we like about Warmer.ai

  • Unlike other tools, it clearly has more templates and generates several lines that make it indistinguishable from human writing the intro line. Just take a look at this crazy reaction.

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What we dislike:

  • Unlike other tools, you don't get any free lines per month and only get 10 free credits per lifetime.

  • Plans costing 97$/279$/795$ are definitely too high when alternatives like nureply.com exist.

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SalesBlink is an automated sales outreach tool that helps find leads, verify emails, & create campaigns. They also have a resource which is a generator that we're checking out today.

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Features of SalesBlink’s Better Email Subject Line Generator:

Pricing: free

Login Required: No

Rate limited: No

Number of Subject Lines Per Hit: 5

AI Model: Proprietary

Why we love Salesblink’s Email Subject Line Generator

  • For every line generator, the Salesblink also shows a beautiful predicted open rate. We do not know the source of this prediction, but the lines are AI-generated and we could find more results than other tools.

  • Like Keap’s generator, it also asks the industry of your email, providing more personalization.

What we dislike:

  • No personalization of the prospect’s name industry or categorizing of the intent of the email.

4. Copy.AI's Free Email Subject Line Generator

Copy.ai is an AI-powered copywriter that generates high-quality copy for your business. They have a free tool that presumably uses AI, to help us generate email subject lines for free.

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Features of CopyAI's Better Email Subject Line Generator:

Pricing: free

Login Required: No

Rate limited: No

Number of Subject Lines Per Hit: 5

AI Model: Proprietary (Presumably GPT-3 AI)

5. WriteCream Email Personalization and Email Copy

Writecream is an AI Writer and Content Generator. They help sales teams write outbound email ice breakers, ad copies and more.

Features of WriteCream Email Personalization & Email Copy

Pricing: Free options (free forever plan available)

Login Required: Yes

Rate limited: Yes - 20 copies per month

Number of Subject Lines Per Hit: 5

AI Model: GPT-3 AI

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What we like about WriteCream

  • Unlike previous subject line generators, you could paste the website or linkedin profile of your prospect and get a personalized intro line.

  • The creativity slider allows us to modify the result of the AI which I found to be really cool.

What we don't like:

  • Subject lines seemed to be pretty generic and independent of the industry.

  • It would be more useful if the intro line generator tool worked with the email copy generator tool instead of having to generate it twice and having to copy paste them.

6. Active Campaign's free Subject Line Generator

Active Campaign claims to be a customer experience automation platform, but in English they help you send personalized emails based on user actions.

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Features of Active Campaign's AI subject line generator:

Pricing: free

Login Required: No

Rate limited: No

Number of Subject Lines Per Hit: 4

AI Model: None

Why we love Active Campaigns's subject line tool:

  • Smooth and nice UI

  • Huge list of possible ice breakers

What we dislike:

  • Not AI powered, infact it runs on the browser. So one could technically hit a ceiling of subject lines.

7. Reply.io Cold Email Subject Line Generator

Reply.io is a sales engagement platform that wants to help you create new and effective subject lines that spark your creativity.

Features of Reply.io cold email subject line generator:

Pricing: free

Login Required: No

Rate limited: No

Number of Subject Lines Per Hit: 6

AI Model: None

Why we love reply.io subject generator tool:

  • Personalization with prospect's name, your company name and prospect's company name has a nice collection of 200+ email subjects you can use.

  • They also have integrations to check email quality which you can also do by generating an email score with inbox pirates.

What we dislike:

  • Not AI-powered, in fact it runs on the browser. So one could technically hit a ceiling of subject lines.

8. Keap's Better Email Subject Line Generator

Keap is a marketing automation tool for entrepreneurs. They have a great subject line generator tool that helps you generate creative subject lines.

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Features of Keap's Better Email Subject Line Generator:

Pricing: free

Login Required: No

Rate limited: No

Number of Subject Lines Per Hit: 5

AI Model: None

Why we love Keap's Email Subject Line Generator

  • Unlike other tools, subject lines generated here are classified using more input from the users like whether the email is a follow-up, newsletter, or promotion.

  • Apart from the main problem/pain point you solve, it also takes input for the result/benefit your customer wants.

What we dislike:

  • Not AI-powered, and generates only a maximum of 30 lines per combination. Useful when used in combination with other tools.

Conclusion

Trying almost 20 tools (I excluded the low-performing ones on this list) I can guarantee you that these generators are a great place to start. While I was initially skeptical I still think they are great ways to get replies if you’re consistent enough. I’d also heavily recommend checking out inboxpirates.com — a free email preview testing extensionthat I built to boost your email open rates.

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