Want to see the subject lines pro marketers use?

I got into the trenches and reached out to over a hundred SaaS founders, agency owners, and marketing/sales consultants (like Sujan Patel of Mailshake and Justin Brooke of Adskills) who are killing it with their businesses to put my own cold email game to the test.

I had one simple ask: to send me their best cold email subject line along with open rate statistics so I could share them with you sumo-lings.

So sit back as I reveal the best cold email subject lines that will inspire you to get creative and cut through the noise.

If you see something you like, steal it and test it!

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BEST COLD EMAIL SUBJECT LINES FROM SAAS FOUNDERS, SALESPEOPLE, AND MARKETERS

1. THE CO-PROMOTION OPPORTUNITY EMAIL

This subject line works well because it's short, lightly personalized, and makes an offer right off the bat — "co-promotion opportunity." It's a little vague, which works well because it piques interest enough to get the prospect to click through.

Best used: for promotion opportunities with companies in your niche. It doesn’t matter if your brand isn’t well-known, but you need to have an audience that is similar in size to your prospect's audience. It’s a win-win offer your prospect would be a fool not to take.

From Sujan Patel, Co-founder at Mailshake

2. THE PARTNERSHIP EMAIL

Staying true to the Lemlist emoji experience, this one-word subject line is straightforward in its proposition but very human with the fist bump emoji. It’s like sending an email to one of your buddies.

Best used: to build partnerships with companies in your target audience.

From Vukasin Vukosavljevic, Head of Growth at Lemlist

3. THE BEST GUEST BLOGGER EMAIL

This subject line is more creative than the usual standardized guest post outreach email; it’s lightly personalized and has an emoji to make the point and keep it human.

Best used: to collaborate on content with another company/blog.

From Nick Dimitriou, Head of Growth at Moosend

4. THE JEDI SALES EMAIL

The team at Salesflare seem to be Star Wars geeks, as they use these references often. It works because it has a clear value proposition, it’s fun, it’s humorous, and everyone gets the reference.

Find funny references that naturally make sense to your audience and get creative to make a more memorable first impression. Make sure you have a clear value proposition that is relevant to your audience.

From Jeroen Corthout, CEO and Co-founder at Salesflare

5. THE SHAMELESS BRIBE

This subject line works because bribing people with free cakes is easy. Obviously, respondents know they aren’t actually getting cake, but it stands out because it’s infused with a little more humor than your usual cold email.

Use a variation of this to collect user feedback on your product. Take it to the next level and get recipients to act by actually giving them something.

From Gal Dubinski, Co-founder at Poptin

6. THE FOMO EMAIL

These subject lines compel the recipient to click out of fear they may miss out on an opportunity. It’s only slightly click-baity, so it works if it’s targeted and solves a problem your recipient has.

Best used: to pitch your product/solution if you know your audience's pain point and you can offer something that will work to resolve it.

From Valerie Frolova, Outreach Specialist at Snov.io

7. THE “IT’S NOT RUDE TO INVITE YOURSELF AS A GUEST” EMAIL

People are generally curious (especially when it involves them). This subject line works because it mentions the recipient and instantly creates intrigue.

Best used: to invite yourself as a guest on a podcast or an event, or to promote your content. Only use it if you actually have something interesting to say and real value to add.

From Will Cannon, Founder at UpLead

8. THE CUNNING EMAIL

This subject line works because it has two layers of personalization; it has the tool name the recipient is using (or used in the past) and their name. It also has a straightforward question that can spark meaningful conversation.

Best used: to reach out to your competitor's audience to build relationships, get information to improve your own product, or to pitch your product if you feel like it can better serve the recipients.

From Laxman Papineni, Co-founder at Outplay

9. THE SNACK EMAIL

The first subject line explains the purpose of the email right away, it’s lightly personalized, and it lets the recipient know who they’re coming from. It builds instant credibility if the recipient is familiar with the brand.

The second subject line is a little deceiving. It's ambiguous enough not to sound too sales-y, but it hits the right strings of the person receiving the email — who doesn’t want a better solution to anything they’re doing?

From Cassy Aite, CEO and Co-founder at Hoppier

10. THE I NOTICED YOU NOTICING ME EMAIL

This subject line is sniper-targeted at prospects who have visited your website. How do you identify website visitors? You use a tool like Albacross to identify their IP address and match them with companies in a database to then find their email address.

Best used: to build relationships with people who are potentially interested in your company.

From Andrei Zinkevich, Founder at ROIplan

11. THE CLASSIC QUICK Q EMAIL

The CTA in this subject line arouses interest, making the recipient wonder what the question will be.

From Olga Mykhoparkina, CMO at Better Proposals

12. THE DIRECT Q EMAIL

This subject line couldn’t be any clearer or more direct. It’s extremely easy for the recipient to reply and it is a great opener for a follow-up.

From Timoté Geimer, Head of Product and Marketing at Elium

13. THE ME + YOU EMAIL

Once you link a prospect's name with your company, it gets them to open and read the first sentence. Obviously, you need to be a brand your audience recognizes for this to be effective.

From Vedran Rasic, CMO at Autoklose

Also received from Alex Circei, CEO and Co-founder at Waydev

14. THE “WE’LL GET YOU BETTER RESULTS” EMAIL

This subject line works because it’s relevant to the recipient and it’s sent from a credible company that is known to get great results.

From David Sharpe, Co-founder and Director at Adzooma

BEST COLD EMAIL SUBJECT LINES FROM AGENCY OWNERS

15. THE MYSTERY EMAIL

It’s human nature to own things, and people are possessive over the stuff they own. This subject line plays with this aspect of human psychology and piques the reader's interest.

People dig a little mystery. This subject line uses a little trickery to pique the recipient's interest and emphasizes it with the triple question mark.

From Justin Brooke, Founder at Adskills

16. THE SHOCK & AWE EMAIL

This subject line plays on your recipient's curiosity. If they don’t miss it in their inbox, it’s almost certain they’ll be compelled to click. It’s slightly click-baity, but you can awe your recipient in the body and show you’ve actually done your homework.

Best used: to get your recipient's attention. What you do with it is up to you — the possibilities are endless.

From Chris Von Wilpert, Founder at Content Mavericks

17. THE CHIMP EMAIL

This subject line is targeted at companies that use Mailchimp for their email marketing. So it’s relevant, comes across as personal, and is intriguing enough for the recipient to open.

From Chase H. Diamond, Partner at Boundless Labs

18. THE ENCHILADA EMAIL

Not sure if the Chief Sumo/Taco Lord Noah Kagan would approve of enchiladas. But who doesn’t like enchiladas? This subject line is a human, straightforward way to invite people on your podcast.

From Devin McPaul, Founder at CLVR

19. THE TIRE PUMP EMAIL

This is an attention-grabbing subject line with two layers of personalization — name and location. It’s highly targeted to prospects who are looking to grow their business.

From Joon K. Lee, Founder at Inquivix

20. THE APOLOGETIC INTERRUPTER EMAIL

Given that you're sending a cold email, prospects will see the subject and wonder "Why is a stranger apologizing to me?"

It takes what is normally a disadvantage (being an unknown quantity) and turns it into an advantage (you raise the prospect's curiosity and they open your email). Then it's down to the rest of your email to entertain and maintain their attention.

Add a small element of personalization to this subject line, like {FirstName}, to maximize its potential.

From Angelo Sorbello, Founder at Astrogrowth

Explanation by Jon Buchan

21. THE I ACKNOWLEDGE YOU EMAIL

I thought the classic ego-bait email (congrats/love your work) was slightly overused. In all honesty, it does sound a little spammy. But apparently, it still works. It comes down to two things: timing and relevance.

Best used: if you have something relevant and timely to say and try to be genuine. Never try to sell something in the first email with this subject line.

From Georgios Chasiotis, Founder at Minuttia

22. THE CLASSIC COLD OUTREACH EMAIL

This one is a standard outreach email, but it has more personalization, which makes it a lot more effective than the usual spammy mass outreach email.

From Austin Mullins, Founder at Conversion Creatives

23. THE STALKER EMAIL

This subject line exploits a mutual experience to create relevancy and pique the interest of the reader.

From Stapho Thienpont, Founder at The Marketing Family

24. THE SERENADE EMAIL

This subject line is a little cheesy. But pop song references make things fun and more personable.

Best used: to follow up on a cold call that was rejected.

From Kinga Odziemek, Founder at Brainy Bees

25. THE DIPLOMATIC EMAIL

This subject line sounds a little dry and political. But it works because it’s clear and direct.

From Alan Silvetri, Founder at Growth Gorilla

26. THE ADVISOR EMAIL

This subject line is targeted and direct, but vague enough to pique the recipient's interest to open the email and read the first sentence.

From Harry Dry, Founder at Marketing Examples

BEST COLD EMAIL SUBJECT LINES FROM FREELANCERS/CONSULTANTS

27. THE PUNCHLINE EMAIL

“Don’t get me wrong, usually I hate using “Re:” in cold emails: It’s tricking the reader and I don’t like that.

However, this subject line admits that it’s trickery immediately. It’s like a mini joke in the subject line. People can get a hearty chuckle, and then they open your email.

Then it's up to the rest of your email to entertain and maintain their attention.”

Jon Buchan, Owner at Charm Offensive

28. THE FEAR-INDUCING EMAIL

People will move faster to avoid pain than to seek pleasure. This subject line plays with that basic premise of human psychology and forces the recipient to open your email out of fear.

From Michael Tasner, Marketing Consultant and CEO at No Joke Marketing

29. THE SNIPER-TARGETED EMAIL

This subject line might not make sense because it’s not contextualized. But it’s the principles behind it that make it so effective. It’s sniper targeted at the recipient and extremely relevant and contextual.

From Dejan Gajsek, Freelance Content/Growth Marketer

30. THE CLASSIC CHECK-IN EMAIL

This subject line is only slightly deceiving. Check-in implies the sender has a relationship with the recipient. However, it works well to get your email opened. Because it involves some level of trickery, make sure you have something of immense value to add to the recipient.

From Jesse Hernandez, Email Deliverability Consultant / Founding partner at MailGenius

31. THE ONE SHOT EMAIL

You only have one shot. One opportunity. This is a classic outreach email. Make sure you have ONE question and don’t get all sales-y.

From Lloyd Yip, LWY Consulting

32. THE OPEN-ENDED Q EMAIL

This subject line works because it’s direct, yet open-ended. It’s a solid way to spark conversation and start building a relationship with your prospect.

From Stephen M. Lowisz, B2B Sales Consultant

33. THE WARM COLD EMAIL

Despite this being a cold email, the fact that it lands in the prospect's inbox creates some credibility with the recipient and piques their interest enough to open and read the first sentence for some context.

From Gonzague de Bellaing, Consultant at Mailwarm

34. THE QUICKIE EMAIL

This is a classic cold outreach subject line that works because of its brevity and clarity.

From Morgan Williams, Freelance Content Marketer, Founder at The B2B Sales Podcast & Enterprise Account Executive at Yelp

UNRAVELING THE PATTERNS OF PROS: COLD SUBJECT LINE BEST PRACTICES

Apart from the subject line, many factors affect open rates, including your brand's reputation, credibility, and targeting. You don’t have direct control over everything, so focus on what you can control.

Here are three tips and best practices I’ve learned after going through all the email responses from the pros.

TIP #1: TARGETING: THE SNIPER VS THE CARPET-BOMBER

Most of the cold emails above have abnormally high open rates, even when comparing them to industry benchmarks for warm emails. This is because they’re highly targeted.^[*]

Almost all were sent to batches of 50-100 researched recipients. You don’t want to be carpet-bombing thousands of people with a templated email that has a minimum level of customized personalization. That’s called spamming.

Marketers who are doing this are “poisoning the well” and ruining it for everyone else. Put in the work to understand your prospects.

Just look at the email Massimo Chieruzzi of AdEspresso received. The sender sent the actual instructions on how to customize an email with the greatest subject line of all time…”Please link to my website.”

Don’t be that guy.

Now, don’t get me wrong. There’s nothing unethical about crafting a beautiful script and using automation to make your cold outreach more efficient.

I use them. The pros use them. No one likes doing robotic, manual tasks. Cold email outreach is time-consuming.

It takes work to do it right, but the results are worth it. It all comes down to how much effort you’re willing to put in.

TIP #2: USE DIGITAL PSYCHOLOGY

Digital psychology is the combination of behavioral economics and psychology. Some examples of digital psychology in the subject lines above are:

• External triggers like call-to-actions that you can have in your subject line.

• Internal triggers like FOMO that make your prospect act out of fear of missing an opportunity.

• Loss aversion: people move faster to avoid pain than to seek pleasure. Use this to get your prospect to act.

• Rewards: everybody likes rewards and appreciation. It releases dopamine. Flatter your prospect. But don’t overdo it and be too cheesy.

• Shameless corruption: bribe people with cakes and other shiny things.

TIP #3: ALWAYS A/B TEST

Most of the subject lines in the examples above have been A/B tested.

It’s easy to get complacent once you have something that’s generating results. There’s always room for improvement. Testing is the only way to know if you’re improving.

Keep it simple. Split-test your subject lines on batches of ~50 recipients.

The image below is a screenshot from Chris Von Wilpert’s cold subject line split test.

Which do you think got a higher open rate?

Hint: I used the winning subject line as his contribution in the shock & awe email.

WANT MORE TIPS TO MASTER YOUR COLD OUTREACH GAME?

Now you have everything you need to craft an effective cold email subject line and get your recipient to click open. But there’s more to get them to reply:

• Craft the perfect email body using these cold email templates.

• Be persistent with follow-up emails.

Before you go, let us know which subject line you can’t wait to steal and put to the test!

Download the Cold Email Subject Line Swipe File