Running cold email campaigns at scale requires more than just sending messages. You need infrastructure that protects your sender reputation, spreads volume across multiple accounts, and centralizes reply management so opportunities don’t slip through the cracks.

Smartlead has become the go-to platform for agencies and sales teams sending tens of thousands of emails weekly. This guide walks through every feature in the platform, from connecting your first email account to managing campaigns that run on autopilot.

Why Use a Dedicated Cold Email Platform

Before diving into Smartlead specifically, it’s worth understanding why platforms like this exist. Traditional email clients and basic automation tools weren’t designed for cold outreach at scale. When you send hundreds or thousands of emails from a single account, email service providers like Gmail and Outlook flag you as suspicious.

Cold email platforms solve this through several mechanisms:

Inbox rotation: Spread sending volume across multiple accounts automatically
Email warmup: Build sender reputation through simulated engagement before launching campaigns
Centralized management: Handle replies from dozens of accounts in one place
Deliverability monitoring: Track placement rates and catch problems before they tank your campaigns

Smartlead excels at all four. The platform offers unlimited email accounts on any plan, built-in warmup, a unified inbox for replies, and SmartDelivery testing to verify emails reach the primary inbox.

Setting Up Email Accounts in Smartlead

Everything starts with connecting email accounts. Navigate to the Email Accounts section in the left sidebar to get started.

Connecting Existing Accounts

If you already have email accounts set up through Google Workspace, Microsoft 365, or an SMTP provider like MailReach, you can connect them directly:

Click Add Email Account in the top right
Select your provider (Google, Microsoft, or SMTP)
For Google/Microsoft: Log in through OAuth and grant permissions
For SMTP: Enter your credentials or drag and drop a CSV file with multiple accounts

The drag-and-drop CSV import is particularly useful when setting up dozens of accounts at once. Format your file with columns for email, password, SMTP server, SMTP port, IMAP server, and IMAP port.

Using Smart Senders for Quick Setup

Smartlead offers an integrated solution called Smart Senders if you want to skip the manual setup process. This feature lets you purchase domains and email accounts directly through the platform.

To set up Smart Senders:

Navigate to Smart Senders in the left sidebar
Select your account type (Google, Outlook, or SMTP)
Enter a domain name or let Smartlead suggest available options
Select how many domains you need (purchasing multiple spreads your risk)
Add sender names for each mailbox you want to create
Optionally add profile pictures (these display in Gmail-to-Gmail sends)
Complete the purchase and let Smartlead configure everything

Smart Senders eliminates the technical overhead of DNS configuration, DMARC setup, and mailbox provisioning. However, you sacrifice control over your infrastructure. If you ever need to migrate to a different platform, you won’t own the admin panel for those domains.

For teams just starting out or testing Smartlead, Smart Senders removes friction. For established operations that want full control, setting up accounts through Google Workspace or Microsoft 365 separately makes more sense.

Configuring Account Settings

Once accounts are connected, click into any account to adjust its settings:

Daily Sending Limits: Set how many emails each account sends per day. Industry best practice suggests keeping this under 50 emails per day per account for cold outreach. Higher volumes increase spam risk.

Time Gap Between Emails: Configure the delay between sends. Spacing emails 3-5 minutes apart mimics human sending behavior and reduces spam flags.

Signature: Add an HTML or plain text signature that gets appended to outgoing emails. Keep signatures minimal for cold outreach—heavy HTML formatting hurts deliverability.

Warmup Settings: Enable or disable warmup for each account and configure warmup volume. More on this below.

Bulk Managing Accounts

When you’re operating at scale with dozens or hundreds of accounts, individual configuration becomes tedious. Use the bulk selection feature:

Click the checkbox in the top left to select all accounts
Or check individual accounts you want to modify
Click the Bulk Actions button
Adjust settings in mass: enable/disable warmup, change sending limits, or assign tags

Tags help organize accounts by client, campaign type, or any other grouping that makes sense for your operation. Filter by tags when assigning accounts to campaigns.

Understanding Email Warmup

Email warmup is the process of building sender reputation for new accounts before sending cold campaigns. Smartlead’s warmup feature sends and receives emails within a network of other Smartlead users, simulating real engagement patterns.

How Warmup Works

When warmup is enabled, Smartlead:

Sends emails from your account to other users in the warmup network
Those accounts open the emails, mark them as important, and reply
If emails land in spam, recipients move them to inbox
This positive engagement signals to email providers that your account is legitimate

The warmup network consists of thousands of real mailboxes across Google, Microsoft, and other providers. This diversity ensures your account builds reputation with multiple ESPs.

Recommended Warmup Duration

New email accounts should warm up for 2-4 weeks before launching cold campaigns. During this period:

Start with low warmup volume (10-20 emails/day)
Gradually increase to 30-50 warmup emails/day
Monitor deliverability through the account health dashboard
Don’t send any cold campaigns until warmup shows healthy metrics

Maintaining Warmup During Campaigns

Critical point: don’t disable warmup when you start sending cold emails. Continue running warmup alongside your campaigns to maintain sender reputation. The warmup activity provides a baseline of positive engagement that offsets any negative signals from cold recipients who don’t engage.

Most teams maintain warmup volume at 15-20% of their total daily sending capacity throughout their campaigns.

Creating Your First Campaign

With email accounts connected and warmed up, you’re ready to launch campaigns. Navigate to Email Campaigns in the left sidebar and click Create Campaign.

Step 1: Name Your Campaign

Enter a descriptive name that helps you identify this campaign later. If you’re running campaigns for multiple clients, include the client name. If you’re testing different approaches, include the test variant.

Good naming conventions:

[Client] - [Offer] - [Date]
[ICP] - [Sequence Type] - [Version]
[Product] - [Territory] - [Month]

Step 2: Upload Leads

Click the leads section to import your prospect list. Smartlead accepts CSV files with contact information. Before importing, you’ll see several options:

Block List Handling: Smartlead maintains a global block list of contacts who have unsubscribed or bounced. By default, the platform filters these out. Toggle the option if you want to override this behavior (not recommended).

Duplicate Detection: Enable “Ignore leads that exist in other campaigns” to prevent re-sequencing contacts already in active campaigns. This is essential for maintaining a good sender reputation and avoiding annoying prospects.

Global Bounce List: Smartlead aggregates bounce data across all users. Consider enabling this filter, though be aware it includes data from campaigns with varying quality.

Field Mapping: Map your CSV columns to Smartlead fields. Essential mappings include:

Email (required)
First Name (for personalization)
Company Name (for personalization)
Any custom variables you want to use in copy

If your lead list came from Apollo, Clay, or another enrichment platform, map relevant fields like job title, LinkedIn URL, or custom research points.

Step 3: Write Your Sequence

The sequence editor is where you craft your outreach emails. Write compelling copy that speaks to your prospect’s challenges—this tutorial focuses on the platform mechanics, not copywriting.

Subject Line: Enter your subject line in the designated field. Variables are supported: {{first_name}}, {{company}}, etc.

Email Body: Write your email in the main editor. Insert variables using the Variables dropdown or by typing {{variable_name}}. The signature placeholder %signature% inserts the signature configured in your email account settings.

Preview: Click the Preview button to see how your email renders with actual lead data. This catches variable errors before you send.

Test Email: Send a test to your own inbox to verify formatting, links, and overall appearance.

Adding Split Tests

A/B testing is critical for optimizing cold email performance. Click Add Variant to create alternative versions of your email.

Common elements to test:

Subject lines (biggest impact on open rates)
Opening lines (impact on read rates)
Call-to-action language (impact on reply rates)
Email length (short vs. detailed)

Smartlead splits traffic evenly between variants by default. After accumulating enough data, review performance in the campaign analytics to identify winners.

Adding Follow-Up Steps

Most prospects don’t respond to the first email. Adding follow-ups dramatically increases reply rates. Click Add Step to create subsequent emails in your sequence.

Configure the delay between steps (e.g., “4 days after previous email”). Keep follow-ups brief and reference the previous email without re-stating everything.

A typical cold email sequence includes 3-5 touchpoints over 2-3 weeks. Going longer risks annoying prospects without meaningfully increasing responses.

Step 4: Configure Campaign Settings

The Setup tab contains critical settings that affect deliverability and campaign behavior.

Tracking Settings:

Optimized Email (No Open Tracking): Disable open tracking to improve deliverability. Gmail displays warnings when emails contain tracking pixels, and spam filters penalize them. The deliverability benefit outweighs the lost data in most cases.

Lead Prioritization:

Choose whether to prioritize new leads or follow-ups when both are queued. Following up with engaged prospects typically yields better results.

Email Provider Filtering:

Target specific email providers (Gmail only, Outlook only, etc.) if your data or messaging is optimized for certain platforms.

AI Response Categorization:

Enable AI categorization to automatically tag incoming replies as interested, not interested, out of office, etc. This dramatically speeds up inbox management when running high-volume campaigns.

Bounce Protection:

Set a bounce rate threshold to automatically pause campaigns if data quality is poor. This protects your sender reputation from bad lists.

Scheduling:

Configure which days to send (weekdays typically perform best for B2B)
Set active hours based on your prospects’ time zones
Define the maximum number of new leads to contact per day

Sender Account Assignment:

Select which email accounts will send this campaign
Smartlead automatically rotates between assigned accounts
Assigning more accounts allows higher total volume while keeping per-account volume low

Step 5: Review and Launch

The final Review section displays a summary of your campaign configuration:

Preview emails with actual lead data
Send test emails to yourself
Run the Spam Checker to identify problematic words or patterns
Check Readability scores
View the Mobile Preview to ensure emails render well on phones

Running a Spam Test with SmartDelivery

Before launching, use SmartDelivery to test inbox placement:

Click Run Spam Test in the review section
Smartlead sends your emails to a pool of test inboxes across Gmail, Outlook, and other providers
The system reports where each email landed: Primary, Promotions, or Spam
Aim for 90%+ inbox placement before going live

SmartDelivery is a premium add-on ($49-599/month depending on volume), but it’s invaluable for catching deliverability issues before they waste leads.

Launch

Once everything checks out, click Start Campaign to begin sending. Smartlead will:

Distribute leads across your assigned email accounts
Send emails according to your schedule
Automatically send follow-ups based on your configured delays
Track opens (if enabled), clicks, and replies

Managing Replies in the Master Inbox

As responses flow in, you’ll manage them through Smartlead’s Master Inbox (also called Unibox). This centralizes replies from all your email accounts into a single interface.

Navigating the Inbox

The left panel shows all incoming conversations. Click any thread to view the full email chain on the right. Key features:

Filters: Sort by:

Read/unread status
Lead category (interested, not interested, etc.)
Campaign
Email account
Custom tags

Views: Save custom filter combinations as views for quick access. Useful presets:

“Interested leads” for your highest priority follow-ups
“Needs human review” for messages AI couldn’t categorize
“Client X replies” for agency account management

Categorizing Responses

Each reply should be tagged with an outcome:

Interested: Prospect wants to learn more or book a meeting
Not Interested: Polite decline
Wrong Person: Referred to someone else
Out of Office: Automated OOO reply
Meeting Booked: Success outcome
Unsubscribe: Remove from future campaigns
Custom categories: Create your own in Settings

If you enabled AI categorization, Smartlead automatically applies labels to most replies. Review the AI’s work periodically to catch misclassifications.

Replying to Prospects

Respond to interested prospects directly from the Master Inbox:

Click the thread
Click Reply
Write your response
Send

The reply goes out from the same email account that initiated the conversation, maintaining thread continuity.

For interested prospects, your goal is typically booking a meeting. Include your calendar link or propose specific times in your response.

Subsequences

Smartlead supports subsequences—follow-up campaigns triggered by specific responses. For example, if a prospect says “reach out next quarter,” you can add them to a nurture subsequence that contacts them in 90 days.

To move a lead to a subsequence:

Open the thread
Click Add to Campaign
Select the target subsequence
The system handles the timing automatically

Untracked Replies

Some emails arrive that aren’t tied to any campaign—random inquiries to your cold email accounts, for example. These appear in the Untracked Replies section. While not directly relevant to your campaigns, reviewing them occasionally ensures you don’t miss anything important.

Monitoring Campaign Performance

The Global Analytics section provides performance metrics across all your campaigns:

Sent: Total emails sent
Opened: Open rate (if tracking enabled)
Replied: Reply rate
Bounced: Bounce rate (keep under 3%)
Interested: Positive response rate

Click into individual campaigns for granular data including:

Performance by sequence step
Performance by email variant
Performance by email account
Day-over-day trends

Key Metrics to Watch

Reply Rate: The primary success metric for cold email. Healthy campaigns achieve 2-8% reply rates depending on industry and targeting quality.

Bounce Rate: Keep this under 3%. Higher rates indicate list quality issues and damage sender reputation. If bounces spike, pause the campaign and verify your data with a tool like MillionVerifier before continuing.

Interested Rate: Track what percentage of replies are positive. Low interested rates despite healthy reply rates suggest messaging or targeting problems.

Using SmartDelivery for Ongoing Monitoring

Don’t just test deliverability before launch—monitor it continuously. Run weekly SmartDelivery tests to catch reputation issues early.

Signs of deliverability problems:

Inbox placement dropping below 80%
Reply rates declining despite consistent lead quality
Increasing spam folder placement

If deliverability degrades, possible causes include:

Sending volume too high
Warmup disabled or insufficient
Poor list quality (high bounces or complaints)
Problematic email content (spammy language, too many links)
Domain/IP reputation damage

Address these issues before they compound. Sometimes the answer is retiring damaged accounts and spinning up fresh infrastructure.

Advanced Features

Client Management for Agencies

Agencies running campaigns for multiple clients can use Smartlead’s Client Access feature to create separate logins and dashboards for each client. This provides:

White-labeled interface with your branding
Client-specific analytics and reporting
Controlled access to relevant campaigns only
Separate billing if needed

Client management is available on Pro plans and above, with additional per-client fees ($29/client/month).

Integrations

Smartlead integrates with several complementary tools:

HubSpot: Sync leads and activity to your CRM
Clay: Pull enriched data directly into campaigns
ListKit: Import verified leads from ListKit’s database
LeadMagic: Enrich contacts with accurate email and phone data

For custom integrations, Smartlead provides:

API Access: Build custom workflows programmatically
Webhooks: Trigger external actions based on campaign events (new reply, bounce, etc.)

Access your API key in Settings > Your Profile.

Smart Servers

For teams requiring dedicated sending infrastructure, Smart Servers provides custom IP addresses assigned to your campaigns. This isolates your sending reputation from other Smartlead users and provides maximum control over deliverability.

Smart Servers costs $39/server/month and is recommended for high-volume senders (100,000+ emails/month) or agencies managing campaigns with varying quality levels.

Best Practices for Scaling

Successful cold email at scale requires discipline beyond just using the right tools. Based on what top-performing teams do:

Infrastructure

Multiple domains: Spread campaigns across 5-10+ domains to isolate reputation risk
3-5 accounts per domain: Create multiple mailboxes on each domain
Consistent warmup: Never disable warmup, even during active campaigns
Fresh domains for new campaigns: Rotate in new infrastructure periodically

Volume Management

50 emails/day per account: Keep individual account volume low
Ramp gradually: Don’t go from 0 to 10,000 emails overnight
Monitor closely when scaling: Watch deliverability metrics as you increase volume

List Quality

Verify before uploading: Use MillionVerifier or similar to catch bad emails before they bounce
Target precisely: Broader targeting means more disengaged recipients and higher spam complaints
Remove non-responders: After the full sequence, don’t keep contacting people who clearly aren’t interested

Content

Plain text over HTML: Heavy formatting triggers spam filters
No tracking pixels: Disable open tracking for better deliverability
Minimal links: One link maximum, and avoid URL shorteners
Personalization with substance: Generic “I noticed your company…” doesn’t move needles anymore—deep personalization based on actual research does

Comparing Smartlead to Alternatives

Smartlead isn’t the only option for cold email at scale. How does it compare to the main alternatives?

Smartlead vs. Instantly

Instantly is Smartlead’s closest competitor. Both offer unlimited mailboxes, built-in warmup, and similar pricing. Key differences:

Lead database: Instantly includes a built-in lead finder; Smartlead requires external sourcing
Agency features: Smartlead has stronger white-labeling out of the box
AI features: Both offer AI categorization; Instantly’s AI reply agents are more advanced

See our full Instantly vs. Smartlead comparison for detailed analysis.

Smartlead vs. Lemlist

Lemlist focuses more on personalization features like custom images and videos. Smartlead prioritizes deliverability infrastructure. Choose Lemlist for creative campaigns; choose Smartlead for volume and reliability.

Smartlead vs. Woodpecker

Woodpecker is a solid mid-market option with good deliverability. Smartlead offers more aggressive pricing for unlimited accounts, making it more cost-effective at scale.

Getting Started Checklist

Ready to launch your first Smartlead campaign? Follow this sequence:

Sign up for Smartlead’s 14-day free trial
Connect email accounts or purchase through Smart Senders
Enable warmup on all accounts for 2-4 weeks
Build your lead list from Apollo, Clay, ListKit, or your preferred source
Verify emails before uploading to eliminate bounces
Create your campaign with 3-5 email sequence steps
Run SmartDelivery tests to confirm inbox placement
Launch with conservative daily limits
Monitor replies in the Master Inbox
Optimize based on performance data
Scale gradually as results prove out

Cold email remains one of the most effective channels for B2B pipeline generation when executed properly. Smartlead provides the infrastructure to do it at scale without burning your domains or losing track of interested prospects.

Smartlead Tool Profile - Full feature breakdown and pricing
Best Email Warmup Tools - Compare warmup solutions
Instantly vs. Smartlead - Head-to-head comparison
Cold Email Deliverability Guide - Master inbox placement
Automated Cold Email with Instantly - Alternative platform walkthrough

Smartlead Complete Tutorial: From Setup to Scale