Cold Emailing
Feb 12, 2026
CEO and co-founder
Cold Email Service Provider Integration: Connecting to Instantly, Smartlead & Beyond
Why the "Google Workspace to Instantly" pipeline is broken
The traditional cold email workflow looks like this:
Purchase domains from Namecheap or GoDaddy
Manually create MX, SPF, DKIM, and DMARC records in each domain's DNS panel
Buy Google Workspace seats at $7-8.40 per user per month
Create user accounts and wait 24-72 hours for DNS propagation
Connect to your sending platform
This workflow has two problems that compound as you scale.
Linear cost scaling destroys margins
Google Workspace bills grow proportionally with inbox count. At 50 inboxes, you pay $350-420/month just for email seats. Scale to 100 inboxes and infrastructure costs hit $700-840/month. At 200 inboxes, you're spending $1,400-1,680/month before touching domains, warmup tools, or your sending platform.
For agencies targeting 20-30% net margins (the standard range for healthy digital agencies), this cost structure becomes untenable. When infrastructure consumes 25-30% of client billings, you squeeze gross margins before delivering a single meeting.
Time debt blocks revenue-generating activities
Manual DNS record creation adds up quickly when done correctly. For 50 domains, you're looking at hours of logging into registrar panels, copying record values, waiting for propagation, and testing with Mail-Tester before campaigns can launch. As one user noted about the traditional approach versus automated alternatives:
"Adding all those records would have probably taken dozens of hours. Instead all records were added within 10 minutes." - Verified user review of Inframail (38 5-star reviews on Trustpilot)
Treat email infrastructure as a service. We automate DNS configuration and inbox provisioning, eliminating manual panel work entirely. Our Ultimate Cold Email Infrastructure Guide for 2026 covers the full conceptual framework.
Core integration protocols: SMTP, IMAP, and API explained
Before diving into platform-specific steps, you need to understand the three protocols that connect your infrastructure to your sending platform.
SMTP: The sending protocol
SMTP (Simple Mail Transfer Protocol) handles outbound email delivery. When you configure SMTP settings, you tell your sending platform how to route messages through your email infrastructure.
Standard port: 587 with StartTLS encryption
Alternative: Port 465 for direct SSL/TLS connections
Purpose: Routes outbound messages to recipient servers
IMAP: The receiving protocol
IMAP (Internet Message Access Protocol) manages incoming messages and reply tracking. Unlike POP3, IMAP keeps emails synchronized across all connected devices.
Standard port: 993 for SSL/TLS connections
Purpose: Syncs replies, tracks engagement, manages warmup
Why it matters: You need BOTH IMAP and SMTP protocols to be set properly to connect an email account to Instantly
API: Automation at scale
APIs enable programmatic mailbox creation and management. After setting up an email API integration, your email-sending process becomes automated and capable of handling large volumes without manual intervention.
Agency benefit: One-click client onboarding
Use case: CRM trigger automatically spins up infrastructure
Access: Check our API documentation for programmatic options
We expose these credentials in a bulk-friendly CSV format specifically designed for import into sending platforms.
Step-by-step: Integrating Inframail with Instantly.ai
This walkthrough covers the exact process for connecting Inframail infrastructure to Instantly. The entire procedure completes in minutes once your inboxes are provisioned.
Step 1: Provision inboxes in Inframail
After purchasing domains through the platform (or transferring existing domains), create your email inboxes. We automatically configure SPF, DKIM, and DMARC records. You can watch the records populate in real-time without touching any DNS panels.
"As soon as you start the process of creating email accounts, it will automatically start adding all the records for you, and show you the process in real-time." - Verified user review of Inframail (38 5-star reviews on Trustpilot)
For a visual walkthrough, our Cold Email Setup: SPF, DKIM, and DMARC video demonstrates the 2-minute setup process for 10+ inboxes.
Step 2: Export credentials to CSV
Navigate to the Update tab in your Inframail dashboard to download CSV files containing your credentials. We include all fields required by Instantly in the CSV export:
Email address
Password
SMTP host and port
IMAP host and port
We pre-format the CSV to eliminate mapping errors during import.
Step 3: Bulk import to Instantly
In Instantly, navigate to Email Accounts on the left sidebar. Click Add New, then select Connect existing accounts, choose Any Provider, and select Bulk Import from CSV. Upload the CSV file you exported from Inframail.
Instantly previews the column mapping. Our export format matches Instantly's requirements, so the columns map automatically without manual adjustment.
Step 4: Verify connections
After import, Instantly runs connection tests on each account. Look for green checkmarks indicating successful SMTP and IMAP connections. If any accounts show errors, the troubleshooting section below covers common issues.
For a complete demonstration, watch My Full Cold Email Setup And Strategy! (Instantly + Inframail) by Jasper Aiken or the InfraMail Setup Tutorial for Cold Email by Shivam Gupta.
Step-by-step: Connecting infrastructure to Smartlead
Smartlead follows a similar bulk import process with minor UI differences.
Upload and verify
Export credentials from Inframail using the same CSV process described in the Instantly section. Open your email accounts section in Smartlead, click "Add Account(s)" and select the bulk upload option.
Download Smartlead's sample CSV to verify your format matches their requirements, then drag and drop your Inframail CSV file into the designated field. Smartlead provides a preview showing immediate feedback on any invalid entries before finalizing the import.
Once uploaded, review the preview to confirm all accounts imported correctly. Smartlead runs connection tests similar to Instantly. The platform's unified inbox feature consolidates replies from all connected accounts, eliminating the need to log into 50+ individual inboxes.
For Smartlead-specific guidance on importing from infrastructure providers, refer to the Mailforge/Infraforge to Smartlead import guide which covers similar workflows.
Troubleshooting common connection and deliverability errors
Even with automated setup, connection issues occasionally occur. Here are the most common problems and their fixes.
Error 535: Authentication failed
SMTP error 535 indicates the receiving server rejected your credentials. Common causes:
Incorrect password: Double-check the password in your CSV matches the account
Disabled account: Verify the inbox is active in your infrastructure dashboard
Encryption mismatch: Ensure your sending platform uses the correct security protocol (TLS/SSL)
Fix: Check your current account status in Inframail, verify the username and password, and confirm the SMTP server address and port settings are correct. Our guide on common SMTP mail issue scenarios covers additional edge cases.
Port configuration errors
Connection refused errors often trace back to incorrect port settings:
SMTP ports:
Port 587 with StartTLS (recommended)
Port 465 for SSL/TLS
IMAP port:
Port 993 for SSL/TLS connections
If your sending platform shows "Connection Refused" or timeout errors, verify these ports aren't blocked by your network or firewall. The Mailgun port guide explains when to use each option.
DNS propagation delays
DNS propagation can take 30 minutes to 48 hours for records to update worldwide. In some cases, propagation extends to 72 hours. If you just configured domains and see authentication failures, wait and retry.
Best practice: Use tools like MXToolbox or DNS Checker to verify your SPF, DKIM, and DMARC records have propagated before running campaigns.
Deliverability drops
If connections work but emails land in spam, check these areas:
SPF/DKIM alignment: Verify records match your sending domain
Blacklist status: Check if your IPs or domains appear on Spamhaus, Barracuda, or similar lists
Content triggers: Review email copy for spam keywords
Warmup status: Confirm accounts completed proper warmup before volume sending
Our dashboard includes blacklist monitoring with automatic delisting requests when domains get flagged.
"K and the team are always there to help. The technical set up of hosting and seeing cold email can be daunting as there are a lot of items to consider and manage." - Verified user review of Inframail (38 5-star reviews on Trustpilot)
The economics of integration: Flat-rate vs. per-inbox TCO
Calculate Total Cost of Ownership across realistic inbox counts. The numbers reveal why agency founders switch: flat-rate infrastructure protects margins as you scale.
TCO comparison: 50 inboxes
Cost Component | Google Workspace | Inframail |
|---|---|---|
Email seats/platform | $350-420/month | $129/month |
Monthly infrastructure | $350-420 | $129 |
Annual infrastructure savings: $2,652-3,492
Note: Domain costs apply to both options and vary based on registrar and TLD selection. Standard .com domains cost $10-20 per year through most registrars.
TCO comparison: 100 inboxes
Cost Component | Google Workspace | Inframail |
|---|---|---|
Email seats/platform | $700-840/month | $129/month |
Monthly infrastructure | $700-840 | $129 |
Annual infrastructure savings: $6,852-8,532
TCO comparison: 200 inboxes
At 200 inboxes, the disparity compounds dramatically. Google Workspace infrastructure alone runs $1,400-1,680/month. We charge $129/month regardless of inbox count.
"So affordable that it will make your unit economics work, even for lower ticket b2b businesses like ours." - Verified user review of Inframail (38 5-star reviews on Trustpilot)
The flat-rate model means adding clients doesn't proportionally increase infrastructure costs. Your margins improve as you scale rather than compress. For detailed calculations, see our Cold Email Infrastructure ROI Calculator.
Advanced API integrations for agency workflows
For agencies running multiple client campaigns, API access enables programmatic infrastructure management.
Automated client onboarding
A typical automated workflow looks like this:
CRM trigger: Client status changes to "Onboarding" in HubSpot or Pipedrive
Webhook fires: Zapier or Make detects the status change
API call: Triggers mailbox creation in Inframail
Credentials export: System generates CSV automatically
Notification: Slack message confirms setup completion
This reduces client onboarding from hours of manual work to minutes of automated processing. The Inframail API documentation covers available endpoints and authentication.
Integration with enrichment tools
API-connected infrastructure works with data enrichment platforms for prospect research, lead scoring systems, and CRM workflows that trigger campaigns based on account signals.
Security and compliance best practices
Managing 50+ email accounts creates security considerations. Here's how to handle them properly.
Authentication security
When using bulk SMTP connections, implement these safeguards:
Strong passwords: Use unique, complex passwords for each inbox
Credential storage: Keep CSV files encrypted and delete after import
Access control: Limit who can export credentials from your infrastructure dashboard
Master inbox strategy
Rather than logging into dozens of accounts to check replies, configure server-side forwarding to a central inbox. Both Instantly and Smartlead offer unified inbox features that aggregate responses across all connected accounts. This simplifies lead tracking and ensures no replies slip through cracks. The unified inbox approach consolidates all your outreach channels into one centralized location.
Data residency considerations
We operate on US-based Microsoft infrastructure with dedicated IPs. If your clients or prospects require EU or APAC data residency, confirm compliance requirements before migration. Our dedicated IP vs shared IP video explains the infrastructure architecture in detail.
For a deeper understanding of how dedicated IPs isolate your sending reputation from shared pool contamination, check our comparison guide.
Checklist for evaluating cold email integration solutions
Use this checklist when comparing infrastructure providers. Copy it to your evaluation document and check items as you research:
Export capabilities:
Does the platform offer bulk CSV export?
Does the CSV format match your sending platform's requirements?
Can you export SMTP and IMAP credentials together?
DNS automation:
Are SPF/DKIM/DMARC records configured automatically?
How long does DNS propagation typically take?
Is manual DNS panel access ever required?
IP infrastructure:
Are IPs dedicated or shared?
How many dedicated IPs are included per plan?
What happens if your IP gets blacklisted?
Pricing structure:
Is pricing flat-rate or per-seat?
How do costs scale at 50, 100, and 200 inboxes?
Are there hidden setup fees or minimum commitments?
Platform compatibility:
Does the provider list compatible email platforms?
Are there known integration issues with your sender?
"We spent months hunting for a reliable cold-emailing stack. After repeated failures with another provider, we trialled two options... we switched back to Inframail. Zero issues since. Rock-solid infrastructure, sharp support, genuinely dependable." - Verified user review of Inframail (38 5-star reviews on Trustpilot)
Ready to cut your infrastructure costs and reclaim setup time? Sign up to Inframail and get started today. Provision unlimited inboxes on dedicated IPs at a flat $129/month, export credentials in minutes, and connect to Instantly or Smartlead before your next client call.
FAQs
How long does it take to migrate 50 domains from Google Workspace to Inframail?
Initial setup in Inframail takes 10-15 minutes for 50 inboxes. DNS propagation requires 30 minutes to 48 hours (typically under 4 hours). Plan for 1-2 business days total before running campaigns.
What's the exact infrastructure cost difference for an agency with 100 inboxes?
Google Workspace: $700-840/month for 100 seats. Inframail: $129/month flat-rate. Annual infrastructure savings: $6,852-8,532. Domain costs are additional for both options.
Will deliverability suffer when moving off Google Workspace?
Dedicated IPs isolate your sending reputation from shared pools. You control your deliverability based on your sending practices alone. We report 9.5/10 on Mail-Tester and 88% inbox rates via GMass testing.
Do I need external warmup tools with Inframail?
Yes, we don't include built-in warmup. External tools like Warmbox or Instantly's native warmup feature are required. Our inbox warmup guide covers the process.
What sending platforms work with Inframail?
We work with Instantly, Smartlead, GMass, Woodpecker, and any platform supporting SMTP/IMAP connections. Check our platform compatibility list for specific integrations.
How do I calculate my email sending capacity?
Use our sending capacity calculator to determine the right plan based on your client count and campaign volume.
Key terms glossary
SMTP (Simple Mail Transfer Protocol): The protocol used for sending outbound emails. Standard port is 587 with StartTLS encryption.
IMAP (Internet Message Access Protocol): The protocol for receiving and managing incoming emails. Standard port is 993 for SSL/TLS. Required for reply detection in cold email platforms.
Dedicated IP: A unique IP address assigned exclusively to your sending infrastructure. Your sending behavior alone determines reputation.
Shared IP pool: An IP address shared across multiple senders. One user's poor practices can impact everyone's deliverability.
SPF (Sender Policy Framework): A DNS record that specifies which servers can send email on behalf of your domain.
DKIM (DomainKeys Identified Mail): A DNS record that adds a digital signature to outgoing emails, verifying sender authenticity.
DMARC (Domain-based Message Authentication, Reporting & Conformance): A DNS policy that tells receiving servers how to handle emails failing SPF or DKIM checks.
DNS propagation: The time required for DNS record changes to update across global servers. Typically 30 minutes to 48 hours.
TCO (Total Cost of Ownership): The complete cost of a solution including platform fees, domain costs, warmup tools, and sending platform subscriptions.
