Email Warmup Guide

Overview

Email warmup is the process of gradually building a sending reputation for a new email account. SmartLead automates this by exchanging emails between accounts in its warmup pool — opening, replying, and marking messages as important to signal to email providers that your account is legitimate. Skipping warmup is the number one reason cold emails land in spam. This guide covers how to configure warmup via the API and when your accounts are ready for live campaigns.

How Warmup Works

SmartLead’s warmup pool consists of thousands of email accounts. When you enable warmup on an account:

SmartLead sends emails from your account to other pool members
Pool members open and reply to your emails automatically
Positive engagement signals (opens, replies, moving from spam to inbox) train email providers to trust your account
Volume increases gradually based on your daily_rampup setting

Day 1:  ████░░░░░░░░░░  (5 warmup emails)
Day 7:  ████████░░░░░░  (19 warmup emails)
Day 14: ██████████████  (33+ warmup emails)
         └── Ready for campaigns

Configuring Warmup on a New Account

When creating an email account, include warmup settings in the payload:

Python

import requests
import os

API_KEY = os.getenv("SMARTLEAD_API_KEY")
BASE_URL = "https://server.smartlead.ai/api/v1"

email_account_payload = {
    "from_name": "Sarah Johnson",
    "from_email": "sarah@yourcompany.com",
    "user_name": "sarah@yourcompany.com",
    "password": "your_app_password",
    "smtp_host": "smtp.yourprovider.com",
    "smtp_port": 587,
    "imap_host": "imap.yourprovider.com",
    "imap_port": 993,
    "max_email_per_day": 40,
    "warmup_enabled": True,
    "total_warmup_per_day": 20,
    "daily_rampup": 2,
    "reply_rate_percentage": 30
}

response = requests.post(
    f"{BASE_URL}/email-accounts/save",
    params={"api_key": API_KEY},
    json=email_account_payload
)

account = response.json()
print(f"Account created with warmup enabled: {account['email_account']['id']}")

Warmup Parameters Explained

Parameter	Description	Recommended
`warmup_enabled`	Turn warmup on/off	`True` for all new accounts
`total_warmup_per_day`	Max warmup emails per day	`20` – `40`
`daily_rampup`	Additional warmup emails added per day	`2` – `3`
`reply_rate_percentage`	Percentage of warmup emails that get a reply	`30` – `40`

Do not set total_warmup_per_day above 40 for new accounts. Sending too many warmup emails too fast can trigger spam filters — the opposite of what you want.

Enabling Warmup on Existing Accounts

Python

# Enable warmup on an existing account
email_account_id = 12345

response = requests.patch(
    f"{BASE_URL}/email-accounts/{email_account_id}",
    params={"api_key": API_KEY},
    json={
        "warmup_enabled": True,
        "total_warmup_per_day": 25,
        "daily_rampup": 2,
        "reply_rate_percentage": 30
    }
)

print("Warmup enabled!")

Warmup Timeline

Here’s what a typical warmup schedule looks like:

Phase	Days	Daily Volume	What’s Happening
Ramp-up	1–7	5 → 19	Building initial reputation
Growth	8–14	20 → 33	Establishing consistent engagement
Stable	14+	33–40	Reputation established, ready for campaigns
Maintenance	Ongoing	15–25	Keep warmup running alongside campaigns

Keep warmup enabled even after you start sending campaigns. SmartLead automatically coordinates warmup and campaign sends to stay within your daily limits. Warmup volume will decrease as campaign sends increase.

Checking Warmup Status

Monitor your account’s warmup progress:

Python

# Get email account details including warmup stats
response = requests.get(
    f"{BASE_URL}/email-accounts/{email_account_id}",
    params={"api_key": API_KEY}
)

account = response.json()
print(f"Warmup enabled: {account.get('warmup_enabled')}")
print(f"Daily warmup limit: {account.get('total_warmup_per_day')}")
print(f"Current rampup: {account.get('daily_rampup')}")

When to Start Campaigns

Your account is ready for live campaigns when:

Warmup has been running for 14+ days without interruption
Inbox placement is above 90% (check your email deliverability score)
No spam folder issues have been flagged
Daily warmup volume has reached a stable level

Verify warmup duration

Confirm the account has been warming up for at least 14 days. Newer domains may need 21–30 days.

Check deliverability

Send a test email to a personal account and verify it lands in the primary inbox, not spam or promotions.

Start with low volume

Begin your campaign with max_new_leads_per_day set to 10–15. Monitor bounce rates and spam complaints for the first few days.

Scale gradually

Increase sending volume by 5–10 leads per day every few days, as long as deliverability metrics remain healthy.

Managing Daily Limits

SmartLead coordinates warmup and campaign sends within your max_email_per_day limit:

max_email_per_day = 40
├── Warmup emails:  15 (auto-adjusted)
└── Campaign emails: 25 (remaining capacity)

As campaign volume increases, warmup volume automatically decreases. If campaign volume drops, warmup ramps back up.

Python

# Update daily email limit
response = requests.patch(
    f"{BASE_URL}/email-accounts/{email_account_id}",
    params={"api_key": API_KEY},
    json={
        "max_email_per_day": 50,
        "total_warmup_per_day": 20
    }
)

DNS Requirements

Proper DNS configuration is critical for deliverability. Ensure these records are set up for your sending domain:

Record	Purpose	Priority
SPF	Authorizes your mail servers to send on behalf of your domain	Required
DKIM	Cryptographically signs emails to verify authenticity	Required
DMARC	Tells receiving servers how to handle SPF/DKIM failures	Required
Custom Tracking Domain	Branded tracking links instead of generic ones	Recommended

Missing or misconfigured DNS records will tank your deliverability regardless of how well your account is warmed up. Set up SPF, DKIM, and DMARC before enabling warmup.

Troubleshooting

Warmup emails are landing in spam

Check your DNS records (SPF, DKIM, DMARC). Reduce total_warmup_per_day to 10 and rebuild gradually. Ensure your sending domain isn’t on any blacklists — check with tools like MXToolbox.

Warmup volume isn't increasing

Verify daily_rampup is set to 2 or higher. Check that the email account credentials (SMTP/IMAP) are still valid and the account isn’t locked. Ensure max_email_per_day is high enough to allow warmup growth.

Deliverability dropped after starting campaigns

Reduce campaign volume immediately. Check bounce rates — if above 5%, your lead list needs better verification. Ensure warmup is still enabled alongside campaigns. Consider pausing campaigns for 3–5 days while warmup rebuilds reputation.

IMAP connection errors

Verify your IMAP credentials and host/port settings. For Gmail, ensure “Less secure app access” is enabled or use an App Password. For Outlook, check that IMAP is enabled in account settings. Ensure 2FA app passwords are being used where required.

Get Started

Core Concepts

Guides

Overview

How Warmup Works

Configuring Warmup on a New Account

Warmup Parameters Explained

Enabling Warmup on Existing Accounts

Warmup Timeline

Checking Warmup Status

When to Start Campaigns

Managing Daily Limits

DNS Requirements

Troubleshooting

What’s Next?

Campaign Setup Guide

Best Practices

Get Started

Core Concepts

Guides

​Overview

​How Warmup Works

​Configuring Warmup on a New Account

​Warmup Parameters Explained

​Enabling Warmup on Existing Accounts

​Warmup Timeline

​Checking Warmup Status

​When to Start Campaigns

​Managing Daily Limits

​DNS Requirements

​Troubleshooting

​What’s Next?

Campaign Setup Guide

Best Practices

Overview

How Warmup Works

Configuring Warmup on a New Account

Warmup Parameters Explained

Enabling Warmup on Existing Accounts

Warmup Timeline

Checking Warmup Status

When to Start Campaigns

Managing Daily Limits

DNS Requirements

Troubleshooting

What’s Next?