Guide to Bulk Email: What It Is & How to Send It

The term bulk email refers to emails sent to a large group of people. But, while it can be tempting and often cost-effective to email blast all recipients on your subscriber list, this approach is usually met with lukewarm engagement and can actually damage your email program’s overall success. That’s why—whether you’re sending an email to one person or 100 million recipients—you need to practice responsible sending. 

Last updated: November 9, 2021




Now, we’re not saying you need to avoid sending mass emails completely, but rather you should be strategic about when you use them. At Twilio SendGrid, we work with thousands of companies that send between 1 and 5 million emails a month, so we’ve seen bulk email both fall short of performance expectations and be used successfully and strategically. To ensure your mass email campaigns fall in the latter category, we’ve put together some of our best practices and tips for scaling your email program.

In this guide, we’ll share what bulk email is, how to send it successfully, and what common pitfalls you need to avoid when sending at volume. Here’s what you need to know as your email program continues to scale and touch hundreds, thousands, and even millions of recipients.

sg france 2021 messengagereport

What is bulk email?

Bulk email, or mass email, is a type of email messaging sent to a large group of people all at once. Sending a message to all or some of your subscribers can be a quick and easy way to spread the word about news or time-sensitive updates affecting your business and customers. 

For example, here are some common topics you might include in a mass email:

  • Company announcements
  • Product updates
  • Service outages 
  • Terms of service updates
  • Coupons or promotions
  • Other marketing campaigns

How does bulk email differ from other forms of email? 

Transactional emails are triggered by a specific user’s behavior and sent to just that individual. This could be an abandoned cart email or a receipt sharing the details of their most recent purchase. Transactional emails are one-to-one emails, as they are sent from your business to one sole recipient. Bulk email, on the other hand, is often called one-to-many email as it is sent from your business to many recipients. 

It’s important to note that bulk email is different from junk mail, which is sent without a recipient’s permission. Mass email is legal as subscribers have opted-in to receive messages from your brand and CAN-SPAM requirements are met. However, due to lack of email targeting and message relevancy, most bulk mail is given another name: graymail. 

Graymail is email that your recipients have opted-in to receive, but don’t actually want in their inboxes. Graymail isn’t considered spam since your recipients have signed up to hear from your business and your brand is a legitimate sender. But, odds are there will be a divide in how valuable your recipients find your email content to be. For example, Recipient A might be elated to see your business’ monthly newsletter in their inbox, while Recipient B, who subscribed only to get a coupon code, will click delete without even opening it every month.

While it can be tempting to send an email blast to your entire database, it’s very rare that all of your subscribers want to hear from you in the same capacity and at the same frequency. Instead of sending messages to everyone in your database, use advanced segmentation to target your messages to specific individuals on your list. This will help ensure only individuals interested in this type of content receive your email, which can help boost engagement, reduce spam complaints, and, most importantly, ensure your audience continues to find value in your communications.

Sg 2021 holiday guide blog opt

How to send mass email?

Looking to send a mass email and don’t know where to start? We’ve put together a brief step-by-step guide to help you ensure your message lands in each of your desired recipient’s inboxes. Here’s how: 

1. Find an email service provider

Before you can send your first email, you’ll need to find an email service provider that can handle the volume of email you want to send and meet your deliverability expectations. At Twilio SendGrid, we consider sending 10 million messages (and more) a month to be truly high volume email, but we offer custom pricing based on whatever email send volume your business needs. Whether you’re sending 100 emails a month or over 10 million, we can help you optimize your email delivery rates and scale your email program. 

2. Get a dedicated IP Address

While you can get by using a shared IP address if you’re only sending a few thousand emails a month, you’ll need to up your game if you’re planning to send hundreds of thousands of emails a month. Sharing an IP address can actually hurt your reputation if another sender using the
IP isn’t sending responsibly. Owning and controlling your own dedicated IP address(es) is a must in order to protect your reputation as you scale.

3. Create an email list

Next, you need to know who you want to receive your message. An email service provider like Twilio SendGrid can help you build your email list and grow your business with simple signup forms you can place directly on your website. 

Just a word of caution, while tempting, never buy an email list. Purchased email lists won’t help you achieve your marketing goals because they contain users who aren’t expecting and don’t want your emails. Not only will purchased email lists experience poor recipient engagement, but they’ll also damage your sender reputation, negatively impact your sender score, and potentially get your email account shut down.

To grow your email lists the right way, create multiple ways for individuals to sign-up for your emails, optimize your opt-in pages, and provide an email preference center so your subscribers can determine what types of messages they receive from your brand and how often they receive them.

Want to grow your email marketing list?

Check out our guide for sustainable growth tips. 

4. Draft your content

Now it’s time to determine what you want your email to say. At Twilio SendGrid, we like to “put ourselves in our customers’ shoes,” so before you draft up your email copy, take a moment to consider what value your email has for your recipients, or why they should want to receive your messages. Thinking about your email from their perspective can help you better tailor your tone, copy, and content to your recipient’s interests, which can help increase your engagement. 

You’ll need to draft up your email copy for your subject linepreview text, and email body, as well as gather or design any visual elements, like images or gifs, to help your email come to life. Of course, you can always choose to use a plain text email as well. 

However you decide to format your message, make sure that every email you send has just one clear call-to-action (CTA). Multiple CTAs can confuse your readers, so ensure your CTA details the next step you want your recipients to take, whether it be downloading an ebook, browsing your newest products, or shopping your latest sale.

5. Start small and work your way up

Unfortunately, you can’t just dive right in and start sending 1 million emails a day. Before you can start sending bulk emails, you need to warm up your IP address and sender domain to prove to internet service providers (ISPs) that you’re a reputable sender.

How can you kick off the process of warming up an IP for large volumes of email traffic? You’ll need to start by sending a small number of emails and gradually increase volume as you go. You’ll also need to monitor your lists and remove any unengaged or invalid contacts, so you increase the likelihood of your recipients opening and clicking your messages. If you have strong engagement and few spam complaints, you can continue to slowly increase the number of emails you send over time until you’ve reached your desired volume.

And there you have it! Now, you know how to send a bulk email blast successfully. But, before you get to sending, keep reading to learn the common mistakes brands make when sending high-volume emails, as well as best practices to take your campaigns to the next level. 



What happens if you send too many emails?

Unfortunately, too much of a good thing can have consequences. Sending too many unwelcome or unengaging emails can impact both your sender reputation and your relationship with your subscribers. While there’s a time and place for an email blast, we encourage you to educate yourself on the effect too many non-targeted emails can have on your email program. 

Here’s a closer look at the consequences that can come along with sending too many unwanted mass emails:

1. Negatively impacting sender reputation

Sending a sudden increase in email volume can get your IP address(es) or domain(s) blacklisted by internet service providers. Once blacklisted, your emails might be blocked by the ISP completely or be filtered into your recipients’ spam folders. Luckily, using responsibly sourced email lists, limiting spam complaints, gradually increasing send volume over time, and reading our How to Email Blast Without Getting Blacklisted blog post can help ensure your business stays a trusted sender.

2. Low engagement

If you send too many unpersonalized and irrelevant emails to your recipients, they may not want to engage with your messages. As a result, you might see a dip in engagement metrics like open rate and click through rate. While experimenting with subject line copy, sender name, and send time can help improve open rates, if your email content continues to disappoint recipients, your engagement won’t budge. 

3. Increase in spam complaints

Sending unengaging or unsolicited content will increase the likelihood that your recipients will mark your messages as spam. Once you get enough spam complaints, ISPs could start blocking your messages, which could mean even the individuals who do want to receive your messages can’t receive them.

4. High unsubscribe rate

Lastly, if your recipients don’t find your messages valuable, they will unsubscribe. Losing subscribers can not only hurt your email metrics, but it can also hurt your ability to meet business goals. 


While subscribers come and go all the time, you should aim for an unsubscribe rate of less than 1% and always work to grow your email list.

meeting of the minds

9 tips for sending engaging email blasts

At Twilio SendGrid, we work with thousands of companies that send between 1 and 5 million emails a month and, over the years, we’ve learned what works and (more importantly) what doesn’t. To help you learn from other’s mistakes, we’ve put together a brief list of bulk email best practices so you can ensure every email you send lands well with your audience and your customer’s internet service providers. 

1. Use multiple IP addresses

At lower volumes, you might be able to get away with having just 2 IPs to separately handle your transactional and marketing messages. Unfortunately, as your volume scales into the millions, you might need additional IPs to keep up with your sending needs. Some companies decide to use multiple IP addresses for different types of messages they send, like transactional/marketing emails, newsletters, and re-engagement campaigns. This process can help you maintain a favorable sender reputation, as emails sent to less engaged recipients will only affect the IP address they’re sent from. 

2. Use a preference center

The best way to know what topics your subscribers care about and how frequently they want to hear from your brand is to ask them. Create an email preference center so when an individual goes to subscribe to your email list, they have the power to opt-in and out of specific forms of communication. For example, maybe an individual only wants to know when you’re having sales but doesn’t care to receive your monthly newsletter and weekly marketing emails. The preference center allows them to self-select which of these emails they receive, allowing you to send more targeted emails without pestering your recipients.

3. Ensure you have explicit permission to email your recipients

We don’t mean to sound like a broken record, but be sure to gather subscribers responsibly and ensure every individual on your list has given you their explicit permission to email them. Avoid purchasing lists and stay CAN-SPAM compliant.

4. Practice good list hygiene and have a sunset policy

Regularly “scrub” your email list by removing inactive, bounced, and other non-engaging email addresses. Proper email list hygiene will help you improve your sender reputation, boost your engagement rates, and reduce the chances of landing on an email deny list.

If recipients haven’t engaged with your emails after a set amount of time, consider “sunsetting” them from your lists by reducing the number of emails they receive or dropping them from your list altogether. This will help improve your overall engagement rates, keep spam complaint rates in check, and decrease the number of spam traps you send to. 

5. Authenticate your email with SPF, DKIM, and DMARC

In the past, implementing SPF and DKIM was all it took to get emails delivered to the major inbox providers. Now, you’ll also want to implement DMARC, which allows you to specify how an ISP should handle emails that weren’t authenticated using SPF or DKIM. In some cases, simply publishing a DMARC record can result in a positive reputation bump.

6. Regularly check your reputation and blacklist status on a regular basis

Keep tabs on both your sender reputation and your brand’s presence on deny-lists as either could be preventing your emails from landing in recipient’s inboxes. 

Helpful sites for checking and monitoring your sender reputation


Resources for checking if your IPs or domains are blacklisted

7. Don’t send your subscribers too much mail

Our 2020 Global Messaging Engagement Report revealed more than half of recipients in the U.S., U.K., Germany, France, and Japan would unsubscribe if they started receiving emails daily. Plus, sending frequency and message irrelevance were the top two reasons contacts opted-out of promotional communications. Keep an email marketing calendar to track all the messages you’re sending and ensure you aren’t hitting one specific audience too often.

8. Leverage re-engagement campaigns

Unengaged audiences can hurt your email program’s performance, but before you kick your inactive recipients to the curb, try using a re-engagement campaign to try to win them back. Start by creating your email list of recipients who haven’t opened one of your emails in a certain amount of time—ideally around one to two months—and then explicitly ask them: do you still want to receive our emails? In the body of your email, give your readers two explicit ways to opt-in or out of your future communications, so you can proactively remove unengaged email addresses

For individuals who re-subscribe to your list, take them to your email preference center so they can set the cadence they’d like to hear from you.


On your unsubscribe page, be sure to ask your recipients why they no longer want to hear from your brand. Their answers can help guide your email marketing strategy moving forward. 

9. Ensure it’s something worth sharing

Before hitting send on a mass email, use this checklist to ensure this is a spam-free message all the subscribers on your list will find interesting:

✓ Will my subscribers want to read this email?

✓ Is my email a positive reflection of my brand?

✓ Does my email have one clear call-to-action?

✓ Does my email deceive or mislead my subscribers in any way? 

✓ Has my email content passed a spam testing tool

✓ Am I getting the right message, to the right subscriber, at the right time?

If your email passes the test and follows the other best practices outlined above, you’re all set to send! 


Do email blasts work?

While email blasts can be a time and resource-efficient way to communicate with your customers, they don’t always result in high engagement. Because mass email is unpersonalized and often irrelevant to the vast majority of your audiences, email marketers typically try to avoid them in favor of sending more targeted, personalized, and segmented communications.

When you’re able to narrow down your targeted list to a specific segment of your buyers, you can better understand and appeal to different prospects and customers.

Think about it. Does it make sense to send the same message to someone who just discovered your brand today and a customer who’s spent the last four years doing business with your brand? Not really.

Your new subscriber will need to be nurtured to gain familiarity with your product or service offerings and what sets you apart from your competitors, while your longtime customer will want to stay up-to-date on sales, item re-stocks, and new product launches.  In fact, our 2021 US Global Messaging Engagement Report found that 61% of US email recipients said a personalization would make an email very or somewhat memorable. So, if you want to deliver the right message at the right time to the right subscribers and reap the engagement rewards, you need to use advanced segmentation.

Getting started with advanced audience segmentation

Audience segmentation is the practice of collecting customer data and targeting specific individuals based on demographic characteristics or on-site behavior to serve them more relevant content. While there are tons of different ways to segment your audience, here are a few common ways you can target specific individuals with your email messages:

  1. Demographics: Gender, age, location, job title, or income level
  2. User behavior: Where an individual is in the sales funnel, what pages of your site they’ve previously visited, or what they’ve previously purchased
  3. Interests: What subjects or causes they care about 
  4. Engagement history: Whether your recipients open every one of your emails or have been ignoring your messages as of late 

Wondering what segmentation looks like in practice? 

Imagine you have a female customer who is only interested in shopping for women’s clothing. Based on her interests and past purchasing behavior, it wouldn’t make sense to send her emails about your new men’s and children’s clothing releases. On the other hand, odds are she’d find an email on the top female clothing trends of the season or your upcoming 50% off sale much more relevant to her needs and interests. Send her an email on those topics and she’ll be much more likely to engage! 

With Twilio SendGrid’s Marketing Campaigns, you can use custom fields to store valuable customer insights that can help you send the right content to the right recipients. Custom fields, reserved fields, and engagement data like opens and clicks, provide unique information you can use to identify contacts for different segments. Plus, these fields will automatically update as your contacts’ traits change, so you know your segments are always accurate. Then, you can easily create personalized Automation emails and Single Sends that directly address the wants and needs of your particular audience.

Jumpstart your email marketing campaigns with Twilio SendGrid

Show me how to send better emails 

sg bulk email guide emailimg

Finding the right bulk email service provider

In order to responsibly and reliably send bulk or mass emails, you need to partner with the right email service provider that can meet and scale with your sending needs. Twilio SendGrid sends over 90 billion emails a month on behalf of our clients with 99.999% uptime. Plus, our platform offers easy yet high-impact segmentation, so you can send personalized emails to exactly the right group of subscribers.

If you’re planning on sending high-volume emails, we have the infrastructure, proven deliverability, and expertise to ensure every one of your many messages lands in your customers’ inboxes. 

Ready to start sending with Twilio SendGrid?

Try our suite of tools for yourself and send up to 100 free messages a day or speak to a member of our team for a price quote customized to your volume sending needs. 

Get started with Twilio SendGrid

Learn how we can help you meet your email goals