Cold Emailing
Jan 8, 2026
CEO and co-founder
How to Connect Inframail to Smartlead: The Complete Integration Guide
Why combine Inframail infrastructure with Smartlead sending?
The math is straightforward, and our reliability is proven with 38 5-star reviews on Trustpilot. Running 50 inboxes on Google Workspace + domains Business Starter costs $350-420/month at $7-8.40 per user. We charge $129/month for unlimited inboxes on our Unlimited Plan. You save $221-291 per month on infrastructure alone.
Your cost advantage compounds as you scale. For 100 inboxes, Google Workspace + domains runs $700-840/month while we stay at $129/month. If your average client pays $2,500/month and uses 20 inboxes, your infrastructure cost drops from 6.7% of billings (Google) to 0.8% of billings (Inframail). One agency founder shared results in a user interview, noting they're booking 200+ appointments per month using this infrastructure approach.
Provider | 50 Inboxes/Month | 100 Inboxes/Month | 200 Inboxes/Month |
|---|---|---|---|
Google Workspace + domains | $350-420 | $700-840 | $1,400-1,680 |
Inframail Unlimited + domains | $129 | $129 | $129 |
Monthly Savings | $221-291 | $571-711 | $1,271-1,551 |
Note on Scalability: Inframail's $129/mo flat rate remains the same whether you have 50 or 400+ inboxes. You only pay for the additional domains. All other providers charge per inbox, meaning your costs explode as you scale.
Beyond cost, setup speed matters. Bulk import cuts your account addition time from 1 hour to 2 minutes when you're connecting hundreds of mailboxes.
For context, Mailforge runs on shared IP infrastructure where your reputation depends on other senders' behavior. We provide dedicated IPs (1 IP on Unlimited, 3 IPs on Agency Pack) so your sending reputation stays isolated. With shared pools, one bad actor gets everyone flagged. You avoid that risk entirely with dedicated infrastructure.
We built our infrastructure on Microsoft's cloud platform with dedicated US-based IPs. For a complete platform walkthrough, watch the Inframail Walkthrough video which covers the registration process through bulk import.
Prerequisites before connecting your accounts
Before you start the integration, confirm you have these items ready. Missing any one delays your campaign launch by 24-72 hours.
Inframail account requirements:
Active subscription (Unlimited at $129/month or Agency Pack at $249/month)
Domains purchased and connected through our platform
DNS propagation complete (we automate SPF/DKIM/DARC)
Smartlead account requirements:
Active subscription on any plan. The Basic Plan at $39/month includes bulk CSV import and unlimited email warmup
No tier restrictions on bulk import functionality
Tools needed:
CSV editor (Excel, Google Sheets, or any text editor). You'll use this for a quick formatting check before upload, though our CSV export is pre-formatted for Smartlead so you rarely need to edit anything.
Our help center covers what email platforms work with Inframail, confirming Smartlead compatibility alongside Instantly, ReachInbox, and others.
Step 1: Export your SMTP credentials from Inframail
We provide a CSV file with all your IMAP details ready to integrate with your preferred sending platform. The export pulls credentials for every inbox you've provisioned.
To export your credentials:
Log into your Inframail dashboard
Navigate to the Dashboard section
Select "Export to CSV" panel and choose your sending platform to export
Download the generated CSV file
The CSV contains the essential fields you need for Smartlead: host addresses, usernames, passwords, and port configurations. Unlike Mailforge's manual export process, we pre-format your CSV for direct Smartlead compatibility. The Inframail Demo 2024 video shows the current interface and export workflow.
Important notes on the export:
Warmup settings embed directly in the CSV with parameters for warmup enabled, warmup limit, and warmup increment
Warmup increment is fixed at 1 email per day during migration setup
Once you download the CSV, you cannot change warmup settings from the dashboard (edit the CSV manually or restart the migration flow)
Step 2: Import bulk inboxes into Smartlead
Smartlead lets you upload bulk CSVs on all subscription tiers. The Basic Plan includes this functionality alongside unlimited email warmup and detailed analytics.
To import your credentials:
Open Smartlead and navigate to Email Accounts
Click "Add Account(s)"
Select the bulk upload or CSV import option
Click "Choose File" and upload your CSV
Map each column to the corresponding Smartlead field
Once you upload the CSV, you'll get a preview with immediate feedback on any invalid details. Common validation catches include warmup numbers set too high or missing passwords.
Column mapping guidance:
Smartlead allows import of up to 20 custom data fields per campaign. Map each column to the relevant Smartlead dropdown option. One formatting rule: custom field titles must not contain spaces. Use hyphens or underscores (e.g., "email-1" or "email_1" instead of "Email 1") for proper mapping.
Verification time depends on your list size. You can continue setting up your campaign while Smartlead validates in the background. Watch the InfraMail Setup Tutorial for a step-by-step visual walkthrough.
Step 3: Configure IMAP and SMTP settings
Since we use Microsoft infrastructure, your server settings follow standard Office 365 configurations. Mailforge setup requires you to verify MX records and manually configure sender domains before export. We handle DNS configuration automatically when you connect domains, so your SMTP credentials work immediately after export.
Setting | Value |
|---|---|
SMTP Host | |
SMTP Port | 587 |
SMTP Encryption | STARTTLS |
IMAP Host | |
IMAP Port | 993 |
IMAP Encryption | SSL/TLS |
Why these specific settings matter:
Port 587 is the most commonly used port for cold email. It begins with a standard connection, then upgrades to encryption using STARTTLS. Port 993 handles receiving emails securely using TLS for reply tracking and bounce detection.
For agencies managing 50+ domains, using the wrong port causes 30-40% of initial connection failures. Port 587 with STARTTLS eliminates that failure mode entirely. The Smartlead Office 365 SMTP settings guide confirms these configurations.
After configuration, click Test Connection in Smartlead. You'll receive a test email confirming the SMTP relay works correctly. For detailed sending platform configuration, the Ultimate Cold Email Infrastructure Guide covers the complete setup process.
Step 4: Syncing warmup schedules and daily limits
We don't include built-in warmup because you get better control configuring it inside Smartlead where your campaigns run. This is critical since Smartlead recently changed their import behavior and no longer auto-enables warmup from CSV files.
Warmup configuration recommendations:
Account Age | Starting Daily Emails | Daily Increment | Target Daily Volume |
|---|---|---|---|
Under 6 months | 5-10 | 30 | |
Over 6 months | 10-15 | 40 |
Limit warmup emails to a maximum of 40 per day according to Smartlead's best practices. After a 2-4 week warmup period, your accounts should be ready for campaign sending.
Daily sending limits:
For dedicated IP infrastructure like ours, the safe limit is 30-50 cold emails per day per inbox during the first 90 days. After that, you can push to 80-100 emails daily if your reply rates stay above 3% and bounce rates stay below 2%. Starting with 30-50 emails daily protects your placement in the primary inbox as you build reputation.
Post-warmup best practice:
Don't start sending campaigns until your warmup score is consistently 90+ for at least 2-3 days. One user interview shows the results possible with proper warmup: 6 calls per day sending cold emails through this infrastructure approach.
Troubleshooting common connection errors
Authentication failed:
Check your CSV for extra spaces before or after passwords
Verify username format matches exactly (use full email address)
Confirm stable internet connection not blocking SMTP relay
Connection refused:
Verify Port 587 for SMTP (not 25 or 465)
Confirm STARTTLS encryption enabled
Check for ISP or firewall limitations blocking port access
Disconnection issues:
Keep daily caps at 40-50 during warmup plus outbound combined
Use one platform per mailbox to prevent double scheduling
When to escalate:
If warmup scores don't improve after 7 days, or you see widespread "sending account error" across multiple inboxes, contact our support team immediately. These signal infrastructure issues rather than configuration problems.
Integration checklist
Use this checklist to verify your setup before launching client campaigns. Skipping any step increases your risk of deliverability issues that force emergency domain rotation:
Inframail subscription active (Unlimited or Agency Pack)
Domains purchased and DNS propagated
SPF, DKIM, DMARC configured automatically
CSV exported from Inframail dashboard
Smartlead subscription active (any tier)
CSV imported via bulk upload
Column mapping verified (no spaces in custom field names)
SMTP configured: smtp.office365.com, Port 587, STARTTLS
IMAP configured: outlook.office365.com, Port 993, SSL/TLS
Connection test successful
Warmup manually enabled for each inbox
Daily limits set to 30-50 emails per inbox
Warmup running for 2-4 weeks before campaigns
Calculate your infrastructure savings
The Inframail-Smartlead integration removes operational drag from scaling outbound. Where manual Google Workspace + domains setup requires enabling 2FA, generating app passwords, and entering credentials one by one, this workflow exports and imports 50+ accounts in minutes.
For agencies running 50-200 domains across multiple clients, the math works clearly:
Your Current Inbox Count | Google Workspace + domains Cost/Month | Inframail Cost/Month | Annual Savings |
|---|---|---|---|
50 inboxes | $350-420 | $129 | $3,012-3,852 |
100 inboxes | $700-840 | $129 | $7,212-8,892 |
200 inboxes | $1,400-1,680 | $129 | $15,612-18,972 |
Those savings fund a $50-60k junior account manager or flow straight to your net margin.
If you're currently evaluating Mailforge, compare the infrastructure approaches. Shared IP pools may save money up front but expose you to reputation risk you can't control. Dedicated IPs cost the same $129/month but protect your sending capacity as you scale.
Start your Inframail account and run your current inbox count through this comparison. For complete domain setup guidance before connecting to Smartlead, watch this video showing our provisioning process.
Frequently asked questions about the Inframail Smartlead integration
Can I use API instead of CSV for this integration?
Yes. Smartlead's API accepts parameters including from_name, from_email, smtp_host, smtp_port, imap_host, and imap_port. The API is rate limited to 60 requests per 60 seconds. For 50 accounts, CSV takes one upload while API requires approximately 50 seconds minimum based on rate limits.
Do I need to enable 2FA or generate App Passwords?
No. We use standard authentication that doesn't require the 2FA and app password workflow that Google Workspace + domains demands. You export credentials directly and import them without additional security steps. For 50 inboxes, this eliminates 45-60 minutes of app password generation time.
How long does Smartlead verification take after import?
Basic validation is near-instant. You'll get immediate feedback on invalid details like missing passwords or excessive warmup settings. Full verification runs in the background while you continue campaign setup.
Is there a maximum number of accounts I can import at once?
Smartlead provides unlimited mailboxes with no artificial caps on connected accounts.
How does this compare to Mailforge integration?
Mailforge runs on shared IP infrastructure where your reputation depends on other users' sending behavior. We provide dedicated IPs (1 on Unlimited, 3 on Agency Pack) so your sending reputation stays isolated. Mailforge setup also requires manual DNS verification before CSV export, while we automate DNS configuration when you connect domains.
Key terms glossary
SMTP (Simple Mail Transfer Protocol): The protocol for sending emails from your inbox to recipients. Configured with server address, port, and authentication credentials.
IMAP (Internet Message Access Protocol): The protocol for receiving and syncing emails. Allows Smartlead to track replies, detect bounces, and manage inbox health.
CSV (Comma Separated Values): The file format for bulk data transfer between Inframail and Smartlead. Contains inbox credentials in structured columns.
Dedicated IP: An IP address used solely by your agency. Your sending behavior alone determines reputation. Shared IP pools (used by Mailforge and some alternatives) expose you to reputation damage when other users on the same IP get flagged for spam.
Warmup: The process of gradually increasing sending volume on new inboxes to build reputation with email providers before running full campaigns.
DNS Propagation: The 24-72 hour period for nameserver changes to spread across global DNS systems. Required before inboxes function properly.
