How to Send 10,000 Cold Emails: New Gmail/Yahoo Limits & Safe Setup

Imagine this: you’ve got a brilliant product or service that you know can transform lives, but there’s one problem—you need to tell people about it. Not just a handful of people, but thousands of potential prospects who could benefit from what you’re offering. This is where cold emailing becomes your superpower. Done right, it’s like having a direct line to your audience, sparking conversations, building connections, and driving results.

But let’s face it: sending cold emails isn’t just about hitting send. Scale it up to thousands—say, 10,000 emails—and it becomes a challenge of deliverability, strategy, and precision. Gmail, Outlook, and Yahoo cap you at 500 emails daily, while Google Workspace maxes out at 2,000. Clearly, conventional methods won’t cut it.

To send 10,000 cold emails at once without landing in spam (and also make money from it), you need two things: the right strategy and a powerful cold email tool like Smartlead. On top of that, you’ll need 68 secondary domains and 200 email accounts (3 email accounts per domain) to make it all work seamlessly.

In this article, we’ll take you step by step through:

Sending cold emails smartly - What you need to send 10,000 cold emails
Best Practices To Follow For Sending Cold Emails

Let’s dive in!

Things You Need To Do Before Sending 10000 Cold Emails

For this part, I am guessing you already have a primary domain and a few email addresses. This is really important for sending cold emails without getting blocked.

Example: Our primary domain is Smartlead.ai.

If you don’t have a primary domain yet, buy one before going to the next part. If you need high-performing domains and mailboxes that are pre-configured, then you can explore SmartSenders.

Sign Up on a Cold Email Tool - Smartlead

If you're thinking how to send bulk cold emails, the first thing you need is a cold emailing software, such as Smartlead. Smartlead lets you add unlimited email accounts, email warm up, create cold email campaigns, set follow-ups, schedule bulk emails, etc. We offer 14-day free trial to help you start sending cold emails immediately.

One of our customers achieved as high as 19% positive reply rate with Smartlead.

Make a list of your needs and set a budget. Go through the features of a cold email tool and see if those align with your needs before buying a cold email tool.

Buy Secondary Domains & Create 200 Email Accounts

Secondary domains are additional domain names that a business or individual gets to complement their main domain.

For example, our primary domain is smartlead.ai, but our secondary domains are

smartleadgrowth.info
smartleadinfo.co
smarterleaderemails.co

Secondary domains are vital in sending bulk cold emails for 2 reasons:

Firstly, they help divide the email-sending load, improving deliverability.
Secondly, instead of using the primary domain and risking its reputation, you can use the secondary domains. This strategy will prevent potential blacklisting issues of the primary domain.

How many secondary domains do you need for 10,000 cold emails?

If you're thinking how to send 1000 cold emails or more, always split your bulk emails into batches—a max of 50 emails per address.

Let’s get into a little math to find the answer to this question.

You want to send 10,000 emails per day. If you can only send 50 emails per address, you will need 200 email addresses (simply 10,000 by 50) to send 10,000 emails.

Now, it’s recommended to create only 3 email addresses per secondary domain.

So, divide 200 by 3. You need 66 to 67 secondary domains. We always recommend buying one or two extra domains. So, buy around 68 secondary domains to send 10,000 mails.

Similarly, if you're wondering how to send 5000 cold emails, you will need 33 to 34 secondary domains and 100 email addresses.

To send 1000 cold emails, 6 to 7 secondary domains are enough with 20 email accounts.

Add Bulk Email Accounts to the Cold Email Tool

Once you’ve the secondary domains and the 200 email accounts, add them to your cold email tool.

If you’re using Smartlead, check out this article for technical assistance.

Email Authentication - DKIM, SPF, DMARC, and MX Records

SPF- Sender Policy Framework

DKIM - Domain Keys Identified Mail

DMARC - Domain-based Message Authentication, Reporting & Conformance.

MX Record - Mail Exchange record

These abbreviations often confuse the daylights out of SDRs, but that’s okay. You’re not alone. Here’s an article on DKIM, SPF, DMARC, and MX Records to help you with everything related to it. If you are buying through SmartSenders, you won't have to worry about setting these up manually.

Warm-Up

Warming up email accounts is a must to see success with cold emails, especially when you’re using new domains and sending 10,000 messages.

Warm up your new email accounts for at least 2 weeks before you start sending cold emails.

Here are resources to help you out with warm-ups:

For 10,000 messages, use a cold email tool with an AI-based warm-up feature, like Smartlead.

How To Send 10000 Cold Emails At Once

Sending 10,000 cold emails is not much different to sending 100 emails. The difference lies in the number of secondary domains, the lead list, and how you segment and schedule it.

Take a look at the cold email checklist and practices before launching your outreach campaign. It will save you from many evident mistakes.

Let’s dig in.

Create a Lead List

The easiest way to create a lead list is to get a cold email tool that comes with a contact list building feature.

For instance, with Smartlead, you can opt for this feature (Listkit integration) and create a targeted lead list with just a few clicks on the Smartlead app itself.

If you want to use a separate platform for creating an email list, you have the below options:

Databases
Email finders and scrapers

A database is a storehouse of info about potential customers. The information includes industry, contact details, company size, locations, and performance metrics. Using various filters, you can search these databases for potential customers that align with your ICP. Apollo.io is one of the most popular B2B databases. Here’s an article on How to use Apollo to create an effective email list

An email finder or scrapper is a tool designed to retrieve email addresses publicly posted on the internet. Popular email scrappers are Clay, GetProspect, Skrapp.io, Hunter.io, etc.

Here are a few more resources to come up with a lead list:

Note: Always verify the lists before launching campaigns or sending cold emails. Use Usebouncer, Bulkemailchecker, and MillionVerifier to verify the contacts.

Upload the Lead List in CSV Format

Organise the downloaded lead list on a Google sheet or Excel doc using various columns to segment it properly.

Now, log in to the Smartlead app and click on the ‘Email Campaign' section from the navigation menu.

On Smartlead, you can either upload the lead list as a CSV file or import it directly from your CRM.

Map the CSV Columns

Next, connect each CSV column to the right dropdown option. If you have extra fields, like "Custom First Line," choose "Custom" in the dropdown. This way, you can include specific info not covered by the standard fields, making your data more personalised.

Afterwards, you will see a pop-up with a summary of the contact list, as shown below.

This summary is extremely crucial for bulk email outreach. Go through it and see if anything needs your attention.

Write the Email Sequence

Once you click “Save & Next”, you will go to the next step—sequences.

This is where you write the email body, subject line, and set the follow-ups for your 10,000-leads cold email campaign.

When writing the email body, check out the “spam checker” section on Smartlead. It will show the words or terms that are likely to alert spam filters.

Go through the results and improve your email copy accordingly.

Set Follow-Ups

Even though you’re sending 10,000 messages, it’s important to follow up to get the best results.

Here’s how we follow up at Smartlead.

Don’t set more than three follow-up emails. Keep a healthy interval between each follow-up email.

Choose Sender Accounts

Once done creating the email sequence, choose the email accounts you want to send from. In this case, you need 200 email accounts for sending 10,000 messages.

choose multiple email accounts for sending cold emails

That’s it. You’ve launched a 10,000-leads campaign successfully. Now, sit back and check the analytics dashboard on your cold email tool.

7 Practices To Send Cold Emails In Bulk Without Getting Blocked

Sending bulk cold emails can be a game-changer when done correctly, but it also comes with risks. If mishandled, email service providers (ESPs) may block your account or flag your messages as spam, damaging your deliverability. To ensure success, follow these seven proven practices:

1. Authenticate Your Domain (SPF, DKIM, and DMARC)

Email authentication builds trust with ESPs and protects against spoofing.

SPF ensures only authorized servers can send emails on behalf of your domain.
DKIM adds a digital signature to verify email integrity and authenticity.
DMARC specifies how to handle emails failing SPF or DKIM checks and provides insights to optimize authentication policies.

Work with your domain administrator to add these records to your DNS settings. Proper authentication is non-negotiable for improving deliverability and maintaining a strong sender reputation.

2. Warm Up Your Email Accounts

Avoid jumping into bulk email campaigns with new email accounts. ESPs monitor sudden spikes in activity and penalize suspicious behavior.

Start by sending 10–20 emails daily to trusted contacts who can engage with them.
Gradually increase volume over 8–12 weeks, allowing time to build a positive sender reputation.

Warming up ensures your accounts are seen as trustworthy by ESPs.

3. Use a Custom Tracking Domain

Using a shared tracking domain can hurt your credibility if others misuse it. Instead:

Set up a custom tracking domain linked to your sending domain.
Add a CNAME record to your DNS settings and configure it in your email platform.

This ensures links in your emails appear authentic, protecting your reputation and boosting deliverability.

4. Include an Unsubscribe Link

Compliance with laws like CAN-SPAM and GDPR isn’t optional.

A clear, accessible unsubscribe link prevents recipients from marking your emails as spam.
Regularly remove unsubscribed contacts to keep your list clean and engaged.

Offering an easy opt-out option not only protects you legally but also improves your engagement metrics.

5. Personalize Your Emails

Generic, one-size-fits-all emails often lead to low engagement and spam complaints. Personalization is key:

Segment your audience based on their needs and preferences.
Use personalization tokens like first names, company names, or industry-specific details.

Thoughtful personalization resonates better with recipients, increasing open and reply rates.

6. Send Emails in Sequences

Instead of sending 10,000 emails in one go, use carefully timed sequences:

Spread emails over several days or weeks to avoid sudden spikes in activity.
Nurture prospects with multiple touchpoints, increasing your chances of conversion.

Sequences help you engage meaningfully while staying under ESP volume thresholds.

7. Stick to Daily Sending Limits

Every ESP has limits. For example:

Gmail allows 500 emails/day for free accounts and 2,000 for Google Workspace.
Office 365 permits up to 10,000 emails/day, with a per-minute limit of 30.

Plan your campaigns carefully to stay within these limits, avoiding flags for excessive activity.

Legal Regulations for Bulk Cold Emails

1. In the US: The CAN-SPAM Act

If you’re targeting prospects in the US, the CAN-SPAM Act sets clear rules for commercial emails, including both B2B and B2C campaigns. Violations can result in fines of up to $50,120 per email. To ensure compliance, follow these key requirements:

Accurate Sender Information: Use correct details in your “from” and “reply-to” fields so recipients can easily identify the sender.
Valid Postal Address: Include your business’s physical address in the email footer.
Clear Opt-out Option: Make it easy for recipients to unsubscribe from future emails.
Honest Subject Lines: Avoid misleading subject lines that don’t match the email content.
Promptly Honor Opt-outs: Remove anyone who unsubscribes without delay.
Responsibility for Third-party Vendors: If you outsource email campaigns, you’re still accountable for compliance.

2. In Europe and the UK: GDPR

The General Data Protection Regulation (GDPR) governs data privacy for EU citizens and impacts how you approach bulk cold emailing in the region. Non-compliance can result in steep penalties—up to €20 million or 4% of your global annual turnover. To send GDPR-compliant emails, keep these rules in mind:

Legitimate interest: Ensure you have a valid reason to contact each prospect, such as relevance to their role or industry.
Transparency: Be clear about how you obtained their contact information. If a prospect requests not to receive further emails, respect their request immediately.
Opt-out option: Include a simple and visible way for recipients to unsubscribe.

In the UK, GDPR remains in effect as part of UK law under the UK GDPR, alongside the Data Protection Act (DPA) 2018.

If your prospects are outside these regions, research and adhere to local email and data privacy laws. By staying informed and following best practices, you can conduct bulk cold email campaigns ethically and legally while building trust with your prospects.

What are the risks of sending cold emails in bulk at once?

Sending too many cold emails at once can lead to several risks, including getting flagged for spam, damaging your sender's reputation, and experiencing higher bounce rates.

To mitigate these risks, adhere to cold email rules and best practices. Use email verification tools to ensure you're sending to valid addresses and avoid spam traps. Slowly ramp up your email volume to build credibility with email service providers. Personalize your emails to avoid generic and spammy content.

Additionally, monitor your email deliverability and engagement metrics continuously. Utilize cold email-sending services that offer advanced monitoring and compliance features to stay within safe gmail sending limits and other providers email sending limits as well as maintain a healthy sender reputation.

How do you integrate cold email outreach with other marketing strategies?

Integrating cold email outreach with other marketing strategies amplifies your overall efforts and creates a cohesive approach.

Start by aligning your cold email campaigns with your broader marketing goals and messaging. Use insights from your content marketing, social media, and paid advertising efforts to inform your email content and targeting.

For example, leverage blog posts and whitepapers as valuable resources in your emails. Coordinate your outreach timing with other campaigns, such as launching a new product alongside a targeted cold email blitz. Track and analyze data across all channels to understand how cold email outreach contributes to your overall marketing performance. Combining these efforts ensures a unified strategy that maximizes reach and effectiveness.

How do you measure the success of a cold email campaign?

Measuring the success of a cold email campaign involves tracking key performance indicators (KPIs) that reflect your campaign goals.

Common KPIs include open rates, click-through rates, response rates, and conversion rates. Utilize bulk email software with robust analytics to monitor these metrics in real time. Pay attention to the quality of responses and the engagement levels of different segments within your email list. A/B testing various elements of your emails, such as subject lines and calls to action, can provide insights into what resonates best with your audience.

Ultimately, the success of a cold email campaign is determined by how well it generates qualified leads and drives tangible business outcomes.

How can you avoid getting your cold emails marked as spam?

Avoiding the spam folder requires a combination of technical setup, content strategy, and adherence to cold email rules.

Ensure your domain and email server settings, such as SPF, DKIM, and DMARC, are correctly configured to establish sender authenticity. Use email verification tools to clean your list and remove invalid addresses.

Craft compelling and relevant subject lines that avoid spammy words or phrases. Personalize your emails to make them more engaging and less likely to be marked as spam. Implement proper opt-out mechanisms and respect unsubscribe requests promptly.

Monitoring your sender's reputation and staying compliant with anti-spam regulations are also vital steps in avoiding the spam folder.

By leveraging these strategies and tools, you can effectively manage large-scale cold email campaigns, ensure high deliverability, personalize at scale, and integrate with other marketing tactics to drive successful outcomes from your cold email outreach efforts.

Final Thoughts

Sending 10,000 cold mails is no different than sending 100 messages. The practices remain the same. If anything that changes is the number of secondary domains and email accounts used for that particular campaign.

If you’re a beginner, I recommend starting small. It will help you understand cold emailing as a process and provide a chance to gain a better understanding of your target audience.

For beginners, 10,000 might be an overwhelming volume. But, if you still want to give it a shot, go ahead.

Feel free to reach out to the Smartlead team on the Slack channel or the customer support team if you need any kind of assistance in sending cold emails.

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Rajashree

Rajashree specializes in strategizing and planning B2B SaaS product marketing content. As a writer turned researcher, she has a deep-rooted affinity for writing data-driven content. With over 8 years of experience in the industry, Rajashree has documented her insights in a series of blogs covering genres such as SEO, Content Marketing, Lead Generation, and Email Marketing. Rajashree’s strategic approach and comprehensive industry knowledge make her a trusted authority in creating content that enhances brand visibility and supports business growth.

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Frequently asked questions

General Questions

What is Smartlead's cold email outreach software?

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.

What is Smartlead, and how can it enhance my cold email campaigns?

Smartlead is a robust cold emailing software designed to transform cold emails into reliable revenue streams. Trusted by over 31,000 businesses, Smartlead excels in email deliverability, lead generation, cold email automation, and sales outreach. A unified master inbox streamlines communication management, while built-in email verification reduces bounce rates.
Additionally, Smartlead offers essential tools such as CNAME, SPF Checker, DMARC Checker, Email Verifier, Blacklist Check Tool, and Email Bounce Rate Calculator for optimizing email performance.

How does Smartlead's unlimited mailboxes feature benefit me?

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.

How does Smartlead, as a cold emailing tool, automate the cold email process?

Smartlead’s robust cold email API and automation infrastructure streamline outbound communication by transforming the campaign creation and management processes. It seamlessly integrates data across software systems using APIs and webhooks, adjusts settings, and leverages AI for personalised content.

The cold emailing tool categorises lead intent, offers comprehensive email management with automated notifications, and integrates smoothly with CRMs like Zapier, Make, N8N, HubSpot, Salesforce, and Pipedrive. Smartlead supports scalable outreach by rapidly adding mailboxes and drip-feeding leads into active campaigns Sign Up Now!

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

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.
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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.
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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?

Smartlead, the best cold email marketing tool, ensures your emails reach the intended recipients' primary inbox rather than the spam folder.
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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.
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2. We deploy high-deliverability IP servers specific to each campaign.
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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 Smartlead help improve my email deliverability rates?

Yes, our cold emailing software is designed to significantly improve your email deliverability rates. It enhances email deliverability through AI-powered email warmups across providers, unique IP rotating for each campaign, and dynamic ESP matching.
Real-time AI learning refines strategies based on performance, optimizing deliverability without manual adjustments. Smartlead's advanced features and strategies are designed to improve email deliverability rates, making it a robust choice for enhancing cold email campaign success.

What features does Smartlead offer for cold email personalisation?

Smartlead enhances cold email personalisation through advanced AI-driven capabilities and strategic integrations. Partnered with Clay, The cold remaining software facilitates efficient lead list building, enrichment from over 50 data providers, and real-time scraping for precise targeting. Hyper-personalised cold emails crafted in Clay seamlessly integrate with Smartlead campaigns.

Moreover, Smartlead employs humanised, natural email interactions and smart replies to boost engagement and response rates. Additionally, the SmartAI Bot creates persona-specific, high-converting sales copy. Also you can create persona-specific, high-converting sales copy using SmartAI Bot. You can train the AI bot to achieve 100% categorisation accuracy, optimising engagement and conversion rates.

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

Certainly, Smartlead cold email tool 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!

Is Smartlead suitable for both small businesses and large enterprises?

Smartlead accommodates both small businesses and large enterprises with flexible pricing and comprehensive features. The Basic Plan at $39/month suits small businesses and solopreneurs, offering 2000 active leads and 6000 monthly emails, alongside essential tools like unlimited email warm-up and detailed analytics.

Marketers and growing businesses benefit from the Pro Plan ($94/month), with 30000 active leads and 150000 monthly emails, plus a custom CRM and active support. Lead generation agencies and large enterprises can opt for the Custom Plan ($174/month), providing up to 12 million active lead credits and 60 million emails, with advanced CRM integration and customisation options.

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 cold email tool offers a multi-channel infrastructure designed to be limitless, allowing you to reach potential customers through multiple avenues without constraints.
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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.

How can Smartlead integrate with my existing CRM and other tools?

Smartlead is the cold emailing tool that facilitates seamless integration with existing CRM systems and other tools through robust webhook and API infrastructure. This setup ensures real-time data synchronisation and automated processes without manual intervention. Integration platforms like Zapier, Make, and N8N enable effortless data exchange between Smartlead and various applications, supporting tasks such as lead information syncing and campaign status updates. Additionally, it offers native integrations with major CRM platforms like HubSpot, Salesforce, and Pipedrive, enhancing overall lead management capabilities and workflow efficiency. Try Now!

Do you provide me with lead sources?

No. 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 humanised email sending patterns and ramping up the sending volume.

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?

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?

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. You can also reach out to us at support@smartlead.ai