Cold Emailing
Jan 29, 2026
CEO and co-founder
Cold Email Infrastructure for Lead Generation Agencies: The 2026 Scaling Guide
Why per-seat infrastructure kills agency margins
The fundamental problem with Google Workspace and Microsoft 365 for cold email is their pricing model. Every inbox you add increases your monthly bill by $7-8.40. This creates what I call the "success tax" where growing your agency actively hurts your unit economics.
Let me run the math on three common agency scenarios:
Provider | 50 Inboxes | 100 Inboxes | 200 Inboxes | IP Type | Setup Time |
|---|---|---|---|---|---|
Google Workspace | $350-420/mo | $700-840/mo | $1,400-1,680/mo | Shared | Manual DNS |
Maildoso | $97/mo | $97/mo | $97/mo | Shared pool | Semi-automated |
Inframail | $129/mo | $129/mo | $129/mo | Dedicated (1-3 IPs) | Fully automated |
At 50 inboxes, you're saving $152.50-222.50 per month versus Google Workspace. At 200 inboxes, that gap widens to $1,271-1,551 monthly. Over a year at the 50-inbox tier, that's $1,830-2,670 in infrastructure savings going directly to your bottom line.
For an agency running 50 inboxes across 8 clients at $3,000/month average retainer ($24,000 monthly revenue), Google Workspace at $420/month represents 1.75% of billings. Inframail at $129/month drops that to 0.54%. That difference protects your target 25-30% gross margin.
The hidden cost compounds the problem. With Inframail, DNS configuration for SPF, DKIM, and DMARC records happens instantly, completing in seconds per domain. When you're managing 50+ domains across multiple clients, manual setup in Namecheap or GoDaddy panels eats significant operational hours. That's time you're not spending on sales calls or client strategy.
"So affordable that it will make your unit economics work, even for lower ticket b2b businesses like ours." - Verified user review of Inframail
The three components of scalable cold email infrastructure
Building infrastructure that scales requires getting three things right:
Automated DNS configuration to eliminate manual setup bottlenecks
Dedicated IP addresses to isolate your sending reputation
Flat-rate inbox provisioning to protect margins as you scale
Miss any one of these and you're leaving money or deliverability on the table.
Automated domain and DNS configuration
Handling dozens or even hundreds of domains quickly becomes a nightmare when managing SPF, DKIM, and DMARC records manually. A single typo in your DNS records can wreck email authentication for an entire domain. Multiply that risk across 50-200 domains and you're playing a dangerous game with client deliverability.
We eliminate this bottleneck entirely. When you add a domain to Inframail (either purchased through us or transferred from GoDaddy/Namecheap), we automatically configure:
SPF records: Specifies which mail servers can send email on your domain's behalf
DKIM records: Adds cryptographic signatures to verify message authenticity
DMARC records: Tells receiving servers how to handle authentication failures
Redirects and forwarders: Routes replies correctly without manual configuration
You can learn how this works in our cold email SPF, DKIM, and DMARC setup video, which shows instant provisioning of unlimited inboxes.
For agencies managing multiple clients, this automation is the difference between launching campaigns the same week you sign a contract versus a 7-10 day delay while you wait for DNS propagation and troubleshoot authentication failures.
Dedicated IP addresses for reputation isolation
A shared IP is an IP address used by multiple senders at the same time. Your email deliverability doesn't depend only on your behavior. It's affected by everyone else sending from that IP. One bad actor in the shared pool can tank inbox rates across all users.
This creates an unacceptable risk for agencies. Imagine explaining to your best client that their campaign deliverability dropped from 80% to 45% because some other company's spammy behavior got your shared IP flagged. Providers like Maildoso use shared IP pools where all customers send through the same infrastructure. That conversation ends with a cancellation notice.
With a dedicated IP, your email reputation is 100% your own since your IP address is used only for your emails. Think of it like driving in a private lane versus a carpool lane where one bad driver causes a pileup.
We provide dedicated US-based IPs with every plan:
Unlimited Plan ($129/month): 1 dedicated IP
Agency Pack ($327/month): 3 dedicated IPs
Our dedicated IP vs shared IP comparison video breaks down exactly why this matters for cold email specifically.
"Outstanding deliverability backed by personable, professional support. 1 on 1 with co-founder was extremely helpful to learning more about deliverability and proper infrastructure set up." - Verified user review of Inframail
Flat-rate inbox provisioning
The third piece is economic: your infrastructure costs cannot scale linearly with your client count. Warmup Inbox costs $15 per inbox per month. Lemwarm starts at $29 per inbox monthly. These costs compound quickly when you're running 50-100+ inboxes.
The flat-rate model changes the math entirely. Our Unlimited Plan at $129/month includes unlimited email inboxes with no per-seat charges. Whether you create 50 or 500 inboxes, your platform fee stays fixed.
This enables strategies that would be financially impossible on per-seat pricing:
Domain rotation pools: Maintain extra domains for rotating out flagged senders without cost penalty
Client segmentation: Separate infrastructure per client without multiplying costs
Testing environments: Spin up test inboxes for deliverability experiments
This flat-rate structure is what allows you to protect that 25-30% net margin target and finally afford the $50-60k junior account manager your agency needs to scale past the founder bottleneck.
"I personally have over 1,000 email accounts with Inframail for one flat price. Adding all those records would have probably taken dozens of hours. Instead all records were added within 10 minutes." - Verified user review of Inframail
Step-by-step: Setting up agency infrastructure in under 10 minutes
Let me walk through the actual workflow for getting from zero to sending-ready. This mirrors what we cover in our Ultimate Cold Email Infrastructure Guide for 2026.
Step 1: Add your domains
You have two options here:
Purchase new domains directly through Inframail (approximately $10-16 per year depending on TLD)
Transfer existing domains from registrars like GoDaddy or Namecheap
The average domain name cost runs around $10-20/year, so budget approximately $0.83-1.50 per domain per month when calculating TCO.
Step 2: Automatic DNS configuration
This is where the time savings become tangible. The moment you add a domain, we automatically configure all authentication records:
SPF records pointing to Microsoft's sending servers
DKIM keys generated and published
DMARC policies configured for authentication
Redirects and email forwarding set up for reply routing
No manual DNS panel work required. The automated process configures all authentication records instantly, with no propagation delay.
Step 3: Provision your inboxes
Create unlimited inboxes under your domains. We generate unique usernames (or you can specify custom ones) and provision each inbox with individual IMAP/SMTP credentials.
Step 4: Export credentials to your sending platform
Once inboxes are ready, export the entire batch as a CSV file. This includes all IMAP/SMTP settings formatted for direct import into platforms that work with Inframail, including Instantly.ai, Smartlead, and Reachinbox.
For a visual walkthrough, watch our InfraMail Setup Tutorial from Shivam Gupta or the Cold Email System Setup with AI in 10min or Less video.
Total Cost of Ownership: Google Workspace vs. Maildoso vs. Inframail
Calculating true infrastructure costs requires looking beyond the platform fee. Here's the complete TCO breakdown for a 50-inbox agency setup across three provider options:
Google Workspace scenario (50 inboxes):
Cost Component | Monthly Cost |
|---|---|
Google Workspace ($7-8.40/inbox) | $350-420 |
Domains (~$16.44/year ÷ 12 × 50) | ~$68.50 |
Warmup tools ($15/inbox) | ~$750 |
Total Monthly TCO | $1,168.50-1,238.50 |
Maildoso scenario (50 inboxes):
Cost Component | Monthly Cost |
|---|---|
Maildoso platform fee | $97 |
Domains (~$16.44/year ÷ 12 × 50) | ~$68.50 |
Warmup tools ($15/inbox) | ~$750 |
Total Monthly TCO | $915.50 |
IP Type | Shared pool (reputation risk) |
Inframail scenario (50 inboxes):
Cost Component | Monthly Cost |
|---|---|
Inframail Unlimited Plan | $129 |
Domains (~$16.44/year ÷ 12 × 50) | ~$68.50 |
Warmup tools (external) | ~$750 |
Total Monthly TCO | $947.50 |
IP Type | Dedicated (isolated reputation) |
The Maildoso option looks slightly cheaper on paper, but the shared IP infrastructure introduces deliverability risk that can cost far more in client churn. Folderly's research confirms that your sender reputation with a shared IP is susceptible to other users' sending behavior. One bad actor can tank your campaigns.
I need to be transparent about warmup: we do not include a built-in warmup tool. You'll need an external service like Warmbox or Mailreach. However, the dedicated IP infrastructure provides reputation control that shared-pool providers can't match.
For detailed guidance on this process, our help center covers how to warm up your inboxes after migrating to Inframail.
"Been using Inframail for 2+ years now... Pretty solid deliverability compared to other platforms I've used in the past." - Verified user review of Inframail
Managing deliverability at scale across multiple clients
Running 50-200 domains across 5-15 clients creates unique deliverability challenges. Here's how to handle them without constant firefighting.
Domain rotation strategy
Keep a rotation pool sized to your client load:
5-8 clients: Maintain extra domains for emergency swaps
9-12 clients: Keep additional buffer for rotation without campaign disruption
13+ clients: Run a larger domain reserve to handle multiple simultaneous flags
Flat-rate pricing makes this economically viable since maintaining extra domains costs only the registration fee ($10-20/year per domain), not additional inbox charges.
Client reputation isolation
Dedicated IPs allow you to separate sending reputation by client or client segment. If one client insists on aggressive list sourcing that generates spam complaints, their behavior won't contaminate campaigns for your other accounts.
Blacklist monitoring
We track domain and IP health with blacklist monitoring and auto-submit delisting requests when flags appear. Our help center explains how to tell if your campaign emails are going to spam and what healthy metrics look like.
"Inframail has been absolute gold in terms of delivering a great customer experience, and allowing me to spin up cold email infrastructure at scale for my clients as easily and fast as possible." - Verified user review of Inframail
Proactive deliverability management
Beyond reactive monitoring, successful agencies implement these practices:
Warmup all new inboxes before adding to active campaigns (14-21 days minimum)
Monitor bounce rates and pause senders exceeding 5% hard bounces
Rotate domains before they hit spam thresholds, not after
Segment by client risk using separate IPs for aggressive vs. conservative senders
For agencies focused on results, our user interview with Jackson Williams covers his cold email strategy, while our interview featuring a $50,000 deal shows the revenue potential of properly configured infrastructure.
Get started with flat-rate infrastructure
The math is straightforward: per-seat pricing creates a success tax that erodes margins as you scale. Flat-rate infrastructure breaks that pattern.
Every month you stay on per-seat pricing costs you $221-291 in unnecessary infrastructure spend versus our Unlimited Plan. That's time and money your agency can't afford to waste.
"We spent months hunting for a reliable cold-emailing stack. After repeated failures with another provider, we trialled two options—Inframail and a competitor. We chose the competitor. A month later, we switched back to Inframail. Zero issues since." - Verified user review of Inframail
Sign up to Inframail and get started today. Our Unlimited Plan at $129/month gives you unlimited inboxes, 1 dedicated US-based IP, automated DNS configuration, and priority support. No contracts, no per-seat charges, no DNS headaches.
"One of the best mailbox infra vendors I have ever used super easy and quick setup and support is practically 24/7 with at max a 2min wait to get a question answered." - Verified user review of Inframail
Frequently asked questions
Does Inframail provide SMTP/IMAP credentials?
Yes. Every inbox includes standard SMTP and IMAP credentials formatted for export to platforms like Instantly, Smartlead, and Reachinbox.
How many domains can I set up per day?
The Unlimited Plan ($129/month) includes unlimited domain setups per day. The Agency Pack increases IP capacity for high-volume agencies.
Is email warmup included?
No. We focus on infrastructure (domains, inboxes, dedicated IPs). You'll need an external warmup tool like Warmbox or Mailreach, typically $15-29 per inbox per month.
Can I transfer existing domains to Inframail?
Yes. Bring domains from GoDaddy, Namecheap, or any registrar. We auto-configure all DNS records after transfer.
What's the difference between normal and phantom redirects?
Our help center covers understanding the difference between normal redirects and phantom redirects. Phantom redirects hide domain redirects from ESPs for better deliverability.
How do I calculate sending capacity for my needs?
Our help article on calculating email sending capacity walks through inbox requirements based on daily send volume.
What's your refund policy?
30-day money-back guarantee. Try the platform with real client campaigns, validate deliverability metrics, then decide.
Can I migrate mid-month from Google Workspace?
Yes. Export your domain DNS settings, transfer to Inframail, and we configure everything within minutes. No campaign downtime required.
Key terminology glossary
SPF (Sender Policy Framework): A DNS record specifying which mail servers can send email on your domain's behalf. Prevents unauthorized senders from spoofing your domain.
DKIM (DomainKeys Identified Mail): Adds a cryptographic signature to outgoing emails. Receiving servers verify the signature to confirm message authenticity.
DMARC (Domain-based Message Authentication, Reporting, and Conformance): A policy telling receiving servers how to handle emails that fail SPF or DKIM checks. Options include none (monitor), quarantine (spam folder), or reject.
Dedicated IP: An IP address used exclusively by your account. Your sending reputation depends only on your behavior, not other users.
Shared IP Pool: An IP address used by multiple senders. All users share the same reputation, meaning one bad actor can affect everyone.
DNS Propagation: The time required for DNS record changes to spread across the internet. With Inframail, DNS records are configured instantly in seconds.
