Boost Your Response Rate with 80 Subject Lines for Cold Emails

Created On:
January 20, 2023
Updated On:
April 25, 2024
Cold Email Subject Lines

Want to increase your open rates? 

Then work on cold email subject lines. FYI, 69% of email recipients report an email after reading the subject line. So, the key to successful email marketing is the subject sentence. 

Read ahead to find the best subject lines for your your next cold email campaign.

Why are Subject Lines Important in Cold Emails?

The email marketing industry is one of the most competitive spaces in recent times. With a total of 347.3 billion emails sent and received every day, it is challenging to catch the recipient’s eye. This is where subject sentences come in. 

When the inboxes are overflowing with messages, the humble cold email subject line plays a pivotal role in determining whether your carefully crafted email gets the attention it deserves. 

Think of it as the virtual equivalent of a firm handshake and an engaging smile – it’s the first impression that can make or break your chances of initiating a meaningful conversation.

So, here are the few points that make subject sentences so important in cold email marketing:

  • Increase open rates
  • Create the best first impression
  • Stand out in a crowded inbox

Increase Open Rates

The primary purpose of a cold email subject line is to entice potential customers to take that crucial step and open your email. Consider it the gateway that stands between your email and the hellish fate of spam triggers. 

A well-crafted subject line can ignite curiosity, evoke interest, and even trigger emotions that prompt recipients to click and explore further.

For example:

Ryan, how about a 5x ROI boost?

If somebody is struggling with ROI, the above subject sentence will catch their attention instantly. They might or might not take the desired action, but they will definitely want to look at the email body. 

Create the Best First Impression

Think about it—when you open your inbox, what catches your eye first? 

It's not the sender's name, not the email's content, but that little nugget of text right at the top—the subject line. 

In a matter of seconds, your recipients will make a snap judgment based on that subject sentence alone. It's like meeting someone for the first time; the initial impression lingers and can influence the course of your relationship.

Here’s an example of how you can do it. 

{Competitor} gained {result} using {tool name}

This type of subject lines create the best first impressions. This tells your recipients

  • Shows the result
  • Reveals competitor’s secret behind their success
  • Gives assurance 

Stand Out in a Crowded Inbox

In today's digital age, standing out is not just a challenge, it’s a necessity. With inboxes flooded with emails ranging from work updates to discount offers, your cold email must do more than just appear in the recipient's list.

It needs to command attention. That's where creativity comes into play. Crafting a subject line that stands out amidst the sea of mundane subject sentences requires a unique blend of creativity, strategy, and understanding of your audience.

You can do that with catchy email subject lines. Sometimes, referring to popular culture in your subject sentences can also do wonders. Here are some subject line examples.

  • Be the Dwight of your sales team
  • That’s what the client said

Your subject line sets expectations for the content inside; it's a promise you must fulfill with valuable content and a genuine intent to establish a personal connection.

So, next time you find yourself struggling to write those perfect subject sentences, remember its significance. It's not just a few words—it's your foot in the door, your introduction, and your opportunity to make a lasting impression. 

Take the time to craft subject lines that resonate with your recipients, and you'll find the doors of engagement swinging wide open.

Secret to Crafting Killer Subject Lines—Research

When it comes to creating subject lines that stop recipients from scrolling past your email, research is the only weapon you have. It's the key to unlocking the door to your audience's minds, and crafting subject sentences that resonate on a personal level.

Read this section to learn how to do it. 

Understand Your Audience Inside Out

Imagine walking into a conversation without knowing anything about the person you're speaking to. That's exactly how sending an email without audience research feels. 

Delving into your target audience's pain points, interests, and preferences is like donning a detective's hat before crafting your subject lines. It’s about becoming intimately familiar with what makes your audience tick. 

The bottom line is—know your audience inside out. You can do this by checking your customers’ conversations with the customer support team. 


Think about it—would you be more likely to open an email that speaks directly to your needs and interests, or one that seems generic and vague? 

Audience research allows you to fine-tune your subject sentences so they resonate with your recipients. It's the art of showing that you understand them, their challenges, and what they're seeking.

Focus on ICP, Buyer Personas & Customer Surveys 

Ideal Customer Profile and buyer personas are the big guns when it comes to audience research. 

Buyer personas and ICPs are like blueprints of your ideal customers, offering insights into their demographics, behaviors, and preferences. They're the foundation upon which you can build laser-focused subject lines. 

And then there are surveys, the direct line to your audience's thoughts. These gems of feedback can provide insights into pain points, desires, and even the words and phrases your audience uses. Armed with the right wordings, you can create subject sentences that feel like they're coming from a friend, not a faceless corporation.

Key Elements of an Effective Subject Line for Cold Email Outreach

Crafting an attention-grabbing subject line for cold emails is an art that involves combining several key elements. Think of these elements as building blocks that come together to create a subject line that not only intrigues but also compels recipients to click the "open" button.


Imagine walking into a store with a confusing sign—you'd likely walk right back out. The same goes for your subject line. 

Clarity is the foundation upon which engaging subject lines are crafted. It's about letting recipients know what's in it for them right from the get-go. Nobody likes guesswork, so make sure your subject line clearly states the purpose of your email. For example:

This tool will help with the expansion


Humans are naturally curious creatures. Tap into that curiosity by crafting subject lines that evoke questions, tease ideas, or hint at valuable information. Think of it as leaving a trail of breadcrumbs that leads recipients straight to your email CTA. 

By sparking curiosity, you're encouraging recipients to take that extra step and take the desired action.

{Competitor company} uses {tool/service}

The secret to 5x boost in ROI


A subject line that resonates is one that addresses the recipient's needs. Your audience is looking for solutions to their problems, so your subject line should clearly show how your email offers value. 

Make it clear that you understand their pain points and are offering a solution or insight that's tailored to them.

High spam rates? Smartlead can help


There's something inherently attention-grabbing about seeing your own name. Incorporating the recipient's name in the subject line adds a personal touch that sets your email apart from the generic crowd. It's like addressing someone directly in a crowded room – it captures their attention and makes them feel valued.

Mark, is there too much on your plate? Try automation


FOMO (Fear of Missing Out) is a real psychological trigger. Creating a sense of urgency in your subject line can be incredibly effective. 

Whether it's a limited-time offer, a webinar registration closing soon, or an upcoming event, the idea that time is running out can nudge recipients to open the email before it's too late.

You need to check this out before the spring sale

Last chance to win 10% off in yearly plans

Different Approaches for Crafting Subject Lines

Crafting subject lines that entice recipients to open your cold emails requires a bit of artistry and a dash of psychology. Let's explore four different approaches that can make your subject lines stand out in the sea of emails.

Curiosity-Driven Subject Lines

Curiosity may have killed the cat, but it's a marketer's best friend. Using curiosity in subject lines is like leaving a trail of breadcrumbs that leads recipients into your email. 

Pose a question, hint at something intriguing, or tease an unexpected twist. The goal is to create an itch they can't help but scratch. For instance:

Guess what we discovered about your industry?

This one secret can transform your productivity

Showcasing Value

Recipients open emails when they know they'll gain something valuable. Benefit-oriented subject lines for emails focus on what's in it for them. 

Highlight the outcomes, solutions, or knowledge they'll gain by opening the email. It's like holding a shiny reward in front of them. For example:

Double your website traffic with these strategies

Unlock insider tips to boost your sales

Trying to write the perfect email copy?
Steal one from 101 Cold Email Templates to save your time. 

Making it Personal

There's magic in a name. Personalized subject lines go beyond the generic and address recipients by their name. It's a signal that the email was crafted just for them. 

Think of it as striking up a conversation at a party—it's more engaging when someone addresses you directly. Examples include:

Ryan, here's a special offer just for you

Samantha, your opinion matters to us

Triggering Action

Urgency and scarcity are powerful motivators deeply embedded in human psychology. These subject lines convey that time is running out or a valuable opportunity is limited. 

It's like signaling, "Act now, or you might miss out!" Such subject lines include:

Last chance to secure your spot in our webinar

Only 24 hours left for this exclusive discount

Remember, these approaches aren't mutually exclusive; you can often combine elements to create even more compelling subject lines. The key is to align your approach with your audience and the message you're conveying. 

Experimentation is your best friend. Test different approaches, gauge responses, and fine-tune your strategy based on what resonates best with your recipients.

80 Best Cold Email Subject Lines to Increase Your Response Rate

Cold emails are emails sent to potential customers with whom the sender had no prior contact. Consider the subject sentence as the first impression. In cold outreach, the first impression is 99% of times the last impression, which is why it's so crucial to nail it with the subject sentences.

In this section, I have discussed in detail about catchy, personalized, intriguing, informative, and short subject lines. Here's a quick overview.

Types of Subject Lines in Cold Emails

Catchy Outreach Email Subject Line

33% of recipients open an email if the subject is catchy enough. Now, what makes a subject catchy? 

Bitter Truth

Sales, in general, include a hyper-positive interaction with the prospects with little to no “NO” or mention of anything that can make the target upset. 

So, one of the best ways to catch the recipient’s attention is by doing the opposite. That doesn’t mean you can say sentences like

❌You will go bankrupt if you do this

❌Recipients will block you if you don’t do this

❌You know nothing

Instead of saying extreme things like the above, you can say something that is relevant and refers to a bitter truth. 

  1. Your emails suck: Why you need to personalize 
  2. Why your kitchen is more automated than sales 
A WORD OF CAUTION ☠️: Never use sentences that have the potential of ruining your relationship with your customers. 

Reference to Trends

Cold Emails Lines for Subject
Image Credits

Something that’s going in the news or viral in Tiktok is popular and catchy. You know that people are already hooked on this topic. This is why, when you are in doubt, it’s safe to use subjects that refer to a current trend. 

Here are some subject line examples: 

  1. Covid is killing the economy. What are you doing about it?
  2. This is how Zuckerberg started

Why will the above sentences work? 

Let’s talk about the first sentence first. So, the economic crisis because of the coronavirus pandemic is a universal thing. Be it Australia or Nigeria, businesses suffered losses all around the globe. 

By saying “Covid is killing the economy,” you have made sure that the recipient, irrespective of their demography, is going to stop scrolling after reading this line. The part of the sentence “what are you doing about it?” makes the reader question themselves and take action. 

The second subject is guaranteed to work if you are targeting a start-up founder. Zuckerberg is still a wonder to many, especially entrepreneurs, how he managed innovation and success at such a young age. The point is that everybody wants to know. 

Everyday Phrases

Email is something that we always go a little formal or official. So, when scrolling through the inbox, something very ordinary such as everyday phrases can catch the recipient’s attention immediately. This type of subject lines are the best for B2B networking.

Some of the examples can be:

  1. Let’s get a cup of coffee
  2. You okay there? 
  3. We need to talk 
  4. I got your back

Reference to Popular Culture

Talking about catchy subjects, popular culture references always work. Obviously, when your recipient gets the reference, otherwise, it’s all lost in translation. ‘

  1. Be the Jim of your sales team
  2. That’s what the customer said
  3. Carpe diem the weekend sales
  4. Could you be more relaxed?

Use Emojis

Although many B2B people claim emojis are a risky thing, this practice can yield great results for B2C marketers. But, of course, implement this keeping in mind your brand image. 

For instance, the audience base of fashion e-commerce might like to see emojis, but customers of yoga teachers might not. Again, use emojis CAREFULLY. Some of the ways users can use it in your subject lines are:

  1.  ⚠️ Last chance! Black Friday sales end in 5 hours 
  2. ❣️ Valentine's day sales are live!
  3.  Find your comfort in the wild ⛺
  4.  🐈 Pamper your pets within your budget 🐈 
  5.   Top 10 Summer trends 🌞 you need to know now
Check out “101+ Cold Email Templates” to Nail Outreach with Ready-Made Templates. 

Personalized Best Cold Email Subject Lines

Best Open Lines for subject in Cold Emails
Image Credits

Did you know 74% of marketers saw customer engagement improvement through personalization?

That’s right; it’s the biggest trend in email marketing right now. If you want to ace cold email outreach programs, you need to start using personalized subjects. 

How to personalize subject lines?

Use Names

One of the most common ways of personalizing email content is to refer to the recipient using their first name.

  1.  Jon, you need to check this out. 
  2. Mark, is there too much on your plate? 
  3. Levy, how does a 5x increased ROI sound to you?
  4. Hey Ross, {mutual connections} says we need to collaborate
According to statistics, around 26% of leading cart-abandoned email subject lines are personalized. If you are an owner of e-commerce or other business-to-customer companies, then using the first name will do wonders. 

However, that’s not enough if you’re a business-to-business marketer. 

Use Business Information

For B2B marketers, personalization needs to go a little deeper than usual. You need to use their business-related information such as their company size, annual revenue, company history, current needs, etc. This type of subjects are the best cold emails subject line for sales.

Some of the ways of doing that are: 

  1.  This tool will help with the expansion
  2.  Your website needs exit pop-ups
  3.  Your website needs a list-building tool
  4.  Is there too much pressure on your sales team? Automation can help
  5.  Congratulations on your first birthday! 
A WORD OF CAUTION ☠️: You can use any information you want but try to limit yourself to using ones that are available on public platforms, such as LinkedIn, Ambition box, Glassdoor, Twitter, etc. 

Refer to Current Events

Besides using names and business-related info, referring to current company events is another way of personalizing subject lines.

  1.  Congratulations on {so-and-so industry-related recognition}!
  2.  This tool will help with {recent company event}

But, talking about the company might not work all the time. If you are targeting a decision maker, it’s effective to personalize the subject line specifically for them. Here are some ways you can do that.

  1.  Congratulations on the promotion!
  2.  Huge fan of your {work} on {so-and-so platform}
  3.  You did a great job with {recent achievement}!

Please note that you can use similar subjects for networking emails too. 

Intriguing Subject Lines for Cold Emails

The best cold email subject lines are always intriguing in some way or the other. A subject line should make the reader curious enough to open the email. You can make the recipient curious in several ways, here are some of them. 

Talk About Competitor

One of the primary ways of using the competitor company’s name in the subject line is by mentioning what they achieved using a particular service or product. Take a look at the example below. 

 1. {Competitor} gained 1k customers/month using automation tools

This sentence is guaranteed to make the recipient curious enough to open the email. Firstly, you are mentioning the competitor that they always wanted to beat. Secondly, you’re also mentioning a target that they have always been trying to achieve. 

Now, the above subject line will work only if you do your research (about the company) thoroughly. You must not go wrong with the archenemy company and the goal. 

Another simple alternative to this is:

  1.  {Competitor} uses {name the product}
  2.  Our clientele includes Facebook & Twitter. You can join too
  3.  Facebook like {so-and-so tool}

Remember, this line will bag a response but you must get the competitor's name right. Some other ways of using a competitor’s name in sales subject lines are:

  1.  {Competitor} achieved {this goal}. Let us help with that
  2.  {Competitor} won {so-and-so award}. You can do too
  3.  {Competitor} was listed in Forbes. You can be there too

Talk about the Industry Legends

If you think using a competitor company’s name is kinda risky for your first-ever email to the prospect, then you can use industry legends. 

For instance, if you’re targeting a pet products business owner, it’s better to go with companies such as Mars Pet or Nestle Purina pet products. 

  1. Mars Pet uses {this service. You should too
  2.  Mars Pet achieved {goal}. Let us help you do that

Another way of doing this is by referring to industry experts’ names in the subject. For example, if the recipient is a salesperson or head of the sales team, you use names like Grant Cardone, Zig Zigler, etc., in the subject lines. 

  1.  Grant Cardone thinks {this tool} is useful
  2.  Neil Patel uses {this service}
  3.  Check out Neil Patel’s secret tool 

Using experts’ names in the subject line is an effective way to increase your open rates. However, never mislead the prospect. When they open the email, eventually, they don’t want to feel cheated. 

Therefore, it’s necessary to stick to the truth only, which means if you want to use Neil Patel’s name in the subject line, it’s better to get his reviews or recommendation. 

Create a Sense of Urgency

Creating a sense of urgency might be the oldest trick in the sales books but it works all the time. You can try the same for writing an effective subject line. 

  1.  Beware of {problems} this holiday sale
  2. This might save you from loses

The above example alerts the recipient about certain problems which they are more likely to face during the “holiday sales.” 

Besides showing your goodwill (of helping people), it also shows that you’re an experienced individual in that matter. These reasons are enough to make the reader curious about the email body. 

  1.  Final hours: 50% off is almost over
  2. Last chance to win 30% off in yearly plans

The "limited time" subject is the classic example of creating an emergency in sales. 

  1.  You need to check this out before the end of this quarter

The above subject creates suspense. You aren’t even letting the recipient know what they need to check out. Just make sure you have something to offer that will help resolve a pain point they are facing during the quarter. 

Create FOMO

Catchy Subject Lines in Cold Email Campaign

FOMO or fear of missing out. In a Forbes article, Latane Conant, the CMO of 6th sense, explains in detail how even B2B marketers tend to make purchases in fear of missing out.  

And, what’s the easiest way to create FOMO other than reviews from famous names? 

According to studies, around 92% of consumers check product reviews before purchasing a product or service. So, if you want to create FOMO in our email outreach programs, I suggest you use something like this:

  1.  {Competitor} is saving 50% expense with {this tool/product}
  2.  {Our tool} is trending 
  3.  Did you know {tool} is used by 10k and more companies
  4.  10 things you didn’t know about email marketing
  5.  You should know this
  6.  {Competitor 1} & {Competitor 2} are using {this tool} 
  7.  5 email marketing trends you should know before 2023

A little exaggeration is okay while writing such subject lines but don’t lie, especially if you’re planning to keep the prospect in the long run. 

Talk About the Pain Point

Sales are probably 50% of your sales techniques/skills and 50% of your research skills. If you can research and find out important things about your potential customers, then it's bingo. 

Talking about finding things about your future customer, the pain point is the most crucial one. It’s like hitting the bull’s eye if you can do that. 

The common pain point area for B2B sellers are:




✔️Customer support

✔️Data tracking

The best part of targeting pain points while cold emailing is that it gives you a thread for your follow-up email. Take a look at some of the examples:

  1.  Struggling to keep track of {pain point}?
  2.  Stop guessing the open rates today
  3.  Tired of higher bounce rates? Start A/B testing today
  4.  Tired of landing in spam? I can help
  5.  Dan, let me help you with {pain point}
  6.  10 tips to solve your {pain point}
  7.  A better idea for {pain point}
  8.  I can help cut 40% annual cost
Struggling with cold emailing? 
Check out this
checklist to nail it in your next attempt. 

Informative Subject Sentences

The intention of cold emailing might be selling your product but that doesn’t have to start that way. Sometimes, especially for high-quality leads, you should try building a relationship by sending value-added products. 

Remember, your goal is to make them open the first email so that you can send follow-ups, bag a response or two, and eventually sell to them. If you want to turn your prospects into loyal customers, try using the below cues in your subject lines. 

Industry news

Most B2B prospects were industry professionals or experts and right now, they are busy running a business. So, if you can curate relevant industry news and save their Forbes-reading time, it would be a win-win situation for both parties. 

  1.  Did you know {industry expert} won this award?

If you can find out the niche the prospect is interested in; the above subject will work for sure. 

  1.  CEO {Name} is reluctant to work in {big company’s name}
  2.  {Big company’s} co-founders regret expansion
  3.  {Competitor} got listed in {industry-related recognition}
  4.  {Big name} wants to sell {company}
  5.  {Company} fires 100 employees for moonlighting 

The best way to use this type of subject line is in newsletters. It will provide value and will help in creating a loyal audience base. 


Here’s how you can use recent trends in the subject lines and increase your open rates. 

  1.  You want to know the top 5 Sales Trends in 2023
  2.  Stop what you’re doing. {This tool} is the newest trend
  3.  {Competitor 1} & {Competitor 2} are using {this software}

Content [audio + video + blog posts]

Sending relevant (cum value-adding) the content in your introduction email to a cold lead is a good strategy. Relevant content in the email sends a message that you have done your homework, you’re professional, and you are there to help them.

B2B prospects are aware of the marketing trends, and they value the recent trend of customer-centric marketing. Try this and thank me later. 

  1.  I saw your post on {topic}. This {content} might help 
  2.  Recent marketing statistics to help your business
  3.  Resources about {so-and-so topic} you need to read right now
  4.  Proven tips to help your {pain point}

The other ways of writing informative subject lines are talking about webinars, classes, and free resource material. You can also talk about product demos. 

Short [Less than 60 characters]

Want to ace outreach email campaigns? 

It’s time to rethink the length of the subject lines. 

Apparently, 82% of marketers do not exceed 60 characters while sending emails to cold leads. 

I think there’s a reason behind it. 

Think about it. Your potential customers are swamped with sales emails from strangers they don’t know anything about. So, your email is definitely not landing in the primary inbox. It’s either in the “promotional” or in the “updates” section. 

As we all skim through the promotional and updates section, our prospects do the same. Now, do the math on how many seconds you get to catch their attention. It’s definitely not more than 1 second. That’s the time you get to make them reach your subject lines. This is why it’s utterly important to keep them within 60 characters. 

  1.  Hey Dany, we should collaborate
  2.  Have you seen this {article/video/podcast}?
  3.  Quick question regarding your {so-and-so project} 
  4.  Are you prepared to welcome {so-and-so period}?
  5.  Tim, let’s cut to the chase
  6.  What’s your process for cold calling?
Wondering how to write follow-up email subject lines?
Check out this article to learn A to Z about follow-up subject sentences.

How to Test an Email Subject Line? 

The success of cold outreach campaigns depends on picking the right subject line. But, how does one know which is the right subject sentence for your campaign?

Fortunately, you don’t have to listen to your gut feeling to pick the right subject for email outreach. Instead, you can just do A/B testing with subject sentences using a cold emailing software like Smartlead. 

A/B testing or split testing is a feature present in cold emailing tools that allows you to test two or more variants of the same email sent simultaneously. Using this feature, you can determine which subject sentence yields better response rates and click-through rates. 

You can use the same feature to test cold email copywriting, in general, personalized opening lines, call-to-action (CTA) messages, or even the complete email sequence if necessary.

Here’s a step-by-step process on how to do A/B testing to test email subject variants. 

Choose a Cold Email Tool

Smartlead Cold Emails

Choose a cold email tool to send 1000s of emails without getting blacklisted. Make sure the tool has features like

  • Warm-up
  • A/B testing
  • Automated follow-ups
  • Auto-mailbox rotation
  • Multi-channel outreach
  • Master inbox
  • API Access
  • Unlimited Seats
  • Webhooks & Integrations

Set Up Your Account 

Email Accounts in Cold Email Subject Lines

To start sending cold emails with an outreach tool, start by creating an account on their platform. Afterward, establish a connection between the tool and your email service provider (ESP).

Do the SPF, DKIM, DMARC & MX set up for better email deliverability, and enhance the overall security and trustworthiness of your email communications. 

Warm Up 

It's crucial to prepare your email account before launching a campaign or sending out bulk emails. Make sure to gradually warm it up over a period of two weeks.

Create the Email Campaign

In the software, find the “add campaign” option and click on it. 

Campaign Manager for Cold Email Subject Lines

Import your Email List

Import List of Subject Lines

Upload your email list to the cold email tool, ensuring it's properly segmented and organized. The lead list must be in csv format like the below file. 

List of Subject Lines for Cold Emails

Write the Subject

Write a catchy, short, subject for the email campaign. 

Write the Email Body

Write the email content, including the body of the email and the call-to-action (CTA).

Create Subject Line Variations

Develop two or more distinct subject lines for the same email content. These will be your A/B test variations.

Set Up A/B Test

Look for the A/B testing feature within the cold email tool. It might be under or at the side of the campaign settings.

On Smartlead, you can do A/B testing by creating variants. 

Click on the "add variant" option.

Subject Lines in Cold Email

To test subject lines, you can keep the email body same but only change the subject sentence in the next variant (variant 2).

Subject Lines Variant in Cold Emails

Once you have created the email variants, click on save & next and you are done. Check once before scheduling the emails. Set the timing keeping in mind the recipient’s time zones. 

Monitor Performance Metrics

Keep an eye on key metrics such as open rates, click-through rates, and engagement. The cold email tool should provide real-time data.

Compare the performance of the two subject line variations. Determine which one had higher open rates or other relevant metrics. If one subject line clearly outperforms the other, use that knowledge to improve your future email subject line strategies.

Common Mistakes in Cold Email Subject Line Copies

Crafting effective subject sentences for cold email campaigns is an art, but it's also about avoiding the pitfalls that can affect your efforts. 

Let's dive into some common mistakes that can derail your subject line game and how to steer clear of them.

Clickbait Conundrum: Promising More Than You Deliver

Using misleading language that promises more than your email can deliver is a classic clickbait mistake. While it might tempt recipients to open initially, it can lead to disappointment and erode trust when they realize the content doesn't match the hype.

This mistake has a higher chance of emails landing in spam, leading to higher bounce rates and spam rates. 

Lengthy Lament: Overloading with Words

Subject lines that resemble a mini-novel are a surefire way to get ignored. Lengthy subject lines not only get cut off in email previews but also overwhelm recipients. Keep it concise and to the point – a teaser, not a thesis.

The ideal subject line shouldn’t be more than 21 characters or five to six words. 

Spammy Language: The Red Flags

Subject lines packed with spam-triggering words like "urgent," "exclusive offer," and excessive exclamation marks can land your cold emails straight into the spam folder. Using such language can damage your credibility and render your efforts futile.

Lack of Relevance

Subject lines that feel disconnected from the recipient's needs or interests are destined to fail. Your subject line should be a bridge that connects their pain points to your solution. Irrelevant subject lines will lead your email messages directly to the junk folder. 

Generic Greetings: The One-Size-Fits-None Approach

Subject lines that lack personalization come across as mass-produced and impersonal. 

Avoid using generic greetings like "Dear Sir/Madam" or "To Whom It May Concern." Instead, address recipients by their name or other personalized details.

Use “Ryan, you need to see this” kind of greetings to create personalized emails. 

Overusing Capitalization and Punctuation: A Loud Shout

Subject lines written entirely in capital letters or with excessive punctuation (!!!) can be off-putting. They come across as shouting rather than engaging, and recipients might perceive them as aggressive or unprofessional.

Inadequate Testing: Skipping the Proofreading

A minor typo or a grammatical error can dent your credibility. Skipping proofreading and testing can result in subject lines that not only look unprofessional but might also fail to convey your intended message.

Compliance and Legal Considerations

When crafting compelling cold email subject lines, it's not just about grabbing attention—it's also about keeping it legal. Understanding the legal norms is crucial to ensure your emails don't get caught in the spam filters or worse.

Keep the following points in mind to avoid any legal issues. 

Comply with CAN-SPAM Act 

In email marketing, the CAN-SPAM Act (Controlling the Assault of Non-Solicited Pornography And Marketing) stands as a guidepost. It applies to commercial emails and mandates certain practices to protect recipients from deceptive or unsolicited messages. 

While the Can-Spam Act is specific to the United States, adhering to its guidelines will prevent you from violating similar legislations like GDPR, the Australian Spam Act, Canada's Anti-Spam Legislation, and others.

Use Accurate Sender Information

One of the hallmarks of compliant email marketing is transparency. Your subject line might entice recipients to open your email, but the sender information reassures them about its legitimacy. 

Always use a recognizable and accurate sender name and email address. Misleading recipients about who you are can lead to mistrust and can even lead to legal consequences.

Provide Opt-Out Mechanism in Emails

Including an opt-out mechanism is not just a legal obligation; it's a sign of respect for your recipients' preferences. Every email you send should include a clear and simple way for recipients to unsubscribe from future emails. 

Ignoring unsubscribe requests or making it difficult for recipients to opt-out not only violates regulations but also damages your reputation.


Dear reader, remember, there’s only one chance for the first impression in the cold emailing world. The prospect sees the subject, either click it or not, and that’s the end. You don’t get another chance to go and explain what you meant in the subject line. 

So, if you intend to stay away from the spam filter, I suggest you work on your subject lines with utmost priority. However, if it’s too much pressure for you, you can pick any of the above examples. But, I would suggest using an AI-driven tool to personalize the subject line using the prospect’s recent happenings. 


What should be avoided in the subject line?

For sales cold email subject lines, you should avoid using sales-y terms, pushy tone, making the recipient guilty, irrelevant emojis, misleading information, etc. to avoid spam folder. Some of the examples are:

  • Sales-y terms such as buy now, 10% off, last-minute deals, steal the deal, etc.
  • Pushy tone such as Open this email NOW
  • Making the prospect guilty by saying Why didn’t you check my last email? 

How do you grab attention in an email subject?

You can grab attention in an email subject line by referring to a competitor company’s name, an industry expert’s review, recent news or trend, or statistics. 

What words trigger spam? 

Words such as money back guarantee, get paid, 50% off, cash overflow, dollars, price, last-minute deals, big bucks, credit, debit, profit, etc. 

What’s a Rich Text element?

The rich text element allows you to create and format headings, paragraphs, blockquotes, images, and video all in one place instead of having to add and format them individually. Just double-click and easily create content.

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Static and dynamic content editing

A rich text element can be used with static or dynamic content. For static content, just drop it into any page and begin editing. For dynamic content, add a rich text field to any collection and then connect a rich text element to that field in the settings panel. Voila!

How to customize formatting for each rich text

Headings, paragraphs, blockquotes, figures, images, and figure captions can all be styled after a class is added to the rich text element using the "When inside of" nested selector system.

Author’s Details

Rajnish Das

Rajnish Das is an in-house writer at SmartWriter and SmartLead. She writes product-oriented, data-driven content for B2B SaaS audiences and educates them on marketing and sales topics. Her expertise includes outbound marketing techniques like cold emailing and LinkedIn outreach.


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Frequently asked questions

General Questions

What is Smartlead's cold email outreach software?

Email automation FAQs- Smartlead

Smartlead's cold email outreach tool helps businesses scale their outreach efforts seamlessly. With unlimited mailboxes, fully automated email warmup functionality, a multi-channel infrastructure, and a user-friendly unibox, it empowers users to manage their entire revenue cycle in one place. Whether you're looking to streamline cold email campaigns with automated email warmups, personalization fields, automated mailbox rotation, easy integrations, and spintax, improve productivity, or enhance scalability with subsequences based on lead’s intentions, automated replies, and full white-label experience, our cold email tool implifies it in a single solution.

How does the "unlimited mailboxes" feature benefit me?

Email automation FAQs- Smartlead

Our "unlimited mailboxes" feature allows you to expand your email communications without restrictions imposed by a mailbox limit. This means you won't be constrained by artificial caps on the number of mailboxes you can connect and use. This feature makes Smartlead the best cold email software and empowers you to reach a wider audience, engage with more potential customers, and manage diverse email campaigns effectively.

What do you mean by "unibox to handle your entire revenue cycle"?

Email automation FAQs- Smartlead

The "unibox" is one of the unique features of Smartlead cold email outreach tool, and it's a game-changer when it comes to managing your revenue cycle. The master inbox or the unibox consolidates all your outreach channels, responses, sales follow-ups, and conversions into one centralized, user-friendly mailbox.

With the "unibox," you gain the ability to:
1. Focus on closing deals: You can now say goodbye to the hassle of logging into multiple mailboxes to search for replies. The "unibox" streamlines your sales communication, allowing you to focus on what matters most—closing deals.

2. Centralized lead management: All your leads are managed from one central location, simplifying lead tracking and response management. This ensures you take advantage of every opportunity and efficiently engage with your prospects.

3. Maintain context: The "unibox" provides a 360-degree view of all your customer messages, allowing you to maintain context and deliver more personalized and effective responses.

How does Smartlead ensure my emails don't land in the spam folder?

Email automation FAQs- Smartlead

Smartlead, the best cold email marketing tool, ensures your emails reach the intended recipients' primary inbox rather than the spam folder. 

Here's how it works:
1. Our "unlimited warmups" feature is designed to build and maintain a healthy sending reputation for your cold email outreach. Instead of sending a large volume of emails all at once, which can trigger spam filters, we gradually ramp up your sending volume. This gradual approach, combined with positive email interactions, helps boost your email deliverability rates.

2. We deploy high-deliverability IP servers specific to each campaign. 

3. The ‘Warmup’ feature replicates humanized email sending patterns, spintax, and smart replies.
4. By establishing a positive sender reputation and gradually increasing the number of sent emails, Smartlead minimizes the risk of your emails being flagged as spam. This way, you can be confident that your messages will consistently land in the primary inbox, increasing the likelihood of engagement and successful communication with your recipients.

Can I integrate Smartlead with other tools I'm using?

Email automation FAQs- Smartlead

Certainly, Smartlead is designed for seamless integration with a wide range of tools and platforms. Smartlead offers integration with HubSpot, Salesforce, Pipedrive, Clay, Listkit, and more. You can leverage webhooks and APIs to integrate the tools you use. Try Now!

Email automation FAQs- Smartlead

What type of businesses sees the most success with Smartlead?

No, there are no limitations on the number of channels you can utilize with Smartlead. Our multi-channel infrastructure is designed to be limitless, allowing you to reach potential customers through multiple avenues without constraints.

This flexibility empowers you to diversify your cold email outreach efforts, connect with your audience through various communication channels, and increase your chances of conversion. Whether email, social media, SMS, or other communication methods, Smartlead's multi-channel capabilities ensure you can choose the channels that best align with your outreach strategy and business goals. This way, you can engage with your prospects effectively and maximize the impact of your email outreach.

Email automation FAQs- Smartlead

Do you provide me with lead sources?

Smartlead distinguishes itself from other cold email outreach software by focusing on limitless scalability and seamless integration. While many similar tools restrict your outreach capabilities, Smartlead offers a different approach.

Here's what makes us uniquely the best cold email software:

1. Unlimited Mailboxes: In contrast to platforms that limit mailbox usage, Smartlead provides unlimited mailboxes. This means you can expand your outreach without any arbitrary constraints.

2. Unique IP Servers: Smartlead offers unique IP servers for every campaign it sends out. 

3. Sender Reputation Protection: Smartlead protects your sender reputation by auto-moving emails from spam folders to the primary inbox. This tool uses unique identifiers to cloak all warmup emails from being recognized by automation parsers. 

4. Automated Warmup: Smartlead’s warmup functionality enhances your sender reputation and improves email deliverability by maintaining humanized email sending patterns and ramping up the sending volume. 

5. Multi-Channel Emphasis: Smartlead places a strong emphasis on multi-channel outreach. You can reach your prospects where they are with the LinkedIn outreach feature.   With Smartlead’s cold email automation software, you're always one step ahead in your outreach efforts, enjoying the freedom to scale your initiatives and seamlessly integrate with other tools—all while maintaining a focus on maximizing the impact of your outreach.

Email automation FAQs- Smartlead

How secure is my data with Smartlead?

Ensuring the security of your data is Smartlead's utmost priority. We implement robust encryption methods and stringent security measures to guarantee the continuous protection of your information. Your data's safety is paramount to us, and we are always dedicated to upholding the highest standards of security.

How can I get started with Smartlead?

Email automation FAQs- Smartlead

Getting started with Smartlead is straightforward! Just head over to our sign-up page and follow our easy step-by-step guide. If you ever have any questions or need assistance, our round-the-clock support team is ready to help, standing by to provide you with any assistance you may require. Sign Up Now!

How can I reach the Smartlead team?

Email automation FAQs- Smartlead

We're here to assist you! You can easily get in touch with our dedicated support team on chat. We strive to provide a response within 24 hours to address any inquiries or concerns you may have.

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