Comparison
Jan 20, 2026
CEO and co-founder
Cold Email Infrastructure for Agencies: Complete Buyer's Guide (2026)
The hidden math: Why per-inbox pricing kills agency margins
The math is straightforward: Google Workspace Business Starter costs $8.40 per user per month on monthly billing, or $7 per month with an annual commitment. With Gemini now included in all business tiers, Google increased prices in 2025.
The problem isn't the per-inbox cost. The problem is linear scaling.
Inbox Count | Google Workspace (Monthly) | Google Workspace (Annual) | Flat-Rate Infrastructure |
|---|---|---|---|
10 inboxes | $84/month | $70/month | ~$140-150/month |
50 inboxes | $420/month | $350/month | ~$185-200/month |
100 inboxes | $840/month | $700/month | ~$250-275/month |
200 inboxes | $1,680/month | $1,400/month | ~$350-400/month |
Note: Flat-rate estimates include platform fee ($129/month) plus domain costs ($10-20/year per domain). Actual costs vary based on domain registrar and quantity.
The breakeven point hits around 15-20 inboxes. Beyond that, flat-rate infrastructure wins every time.
"So affordable that it will make your unit economics work, even for lower ticket b2b businesses like ours." - Verified user review of Inframail
For a complete walkthrough of the cost dynamics, watch our Ultimate Cold Email Infrastructure Guide for 2025 on YouTube.
A worked example: 50-inbox agency P&L
Let's walk through a real agency scenario. You're running 10 clients at $2,500/month retainer for $25,000 monthly revenue. You need 50 inboxes (5 per client for rotation).
Google Workspace infrastructure:
50 inboxes @ $8.40/month = $420/month
Infrastructure as % of revenue: 1.68%
Annual infrastructure cost: $5,040
Flat-rate infrastructure:
Platform: $129/month
Domains (20 @ $12/year): ~$20/month amortized
Warmup (external): ~$30/month
Total: ~$179/month
Infrastructure as % of revenue: 0.72%
Annual infrastructure cost: $2,148
Annual savings: $2,892
That's enough to hire a part-time VA, invest in better prospecting tools, or simply bank as profit margin improvement. Scale to 100 inboxes and the gap widens further.
Defining the landscape: Private vs. distributed infrastructure
Before comparing vendors, you need to understand what you're actually buying. I break the market into three categories:
1. Private email infrastructure
We assign you dedicated IP addresses specifically for your account. Your sending reputation depends entirely on your own behavior. We operate in this category, giving you 1-3 dedicated US-based IPs depending on your plan. The video Dedicated IP vs Shared IP Pools for Cold Email explains why this distinction matters for deliverability.
2. Distributed email infrastructure
These platforms use shared IP pools where multiple users send from the same IP addresses. Your reputation gets affected by other senders on that pool. One bad actor spamming gets the whole IP range flagged. Your inbox rates tank through no fault of your own.
3. Email deliverability center
We provide a dashboard where you monitor domain health, blacklist status, and inbox placement rates. Our platform includes blacklist monitoring with auto-delisting requests built in.
The industry is moving from distributed (renting seats on Google) to private (owning your infrastructure). The reason is control: when you control the IP, you control the reputation. According to Cloudflare's documentation on dedicated IP infrastructure, dedicated IP pools offer reputation isolation and control for high-volume campaigns.
The 4-part scorecard for evaluating infrastructure
Every infrastructure vendor will claim "best deliverability" and "easy setup." These four criteria cut through the marketing:
1. True cost of ownership (TCO)
TCO isn't just the platform fee. It's the complete formula:
Platform Fee + Domain Costs + Warmup Costs + Sending Platform = Total Monthly Infrastructure
Here's the breakdown for 50 inboxes:
Cost Component | Google Workspace | Inframail |
|---|---|---|
Platform fee | $420/month | $129/month |
Domain costs (~20 domains at $12/year) | Included | ~$20/month amortized |
Warmup tool (if external) | N/A | $0-50/month* |
Total | $420/month | $185-235/month |
Warmup cost depends on tool selection. Warmbox runs $29/month for 10 accounts. Alternatively, you can use free warmup via sending platform credits or our Done-for-You package includes warmup management.
According to domain pricing research from Hostinger, domain names cost between $10 and $20 per year to register. For around $11.28 per year, you can register at budget-friendly registrars.
You can calculate your email sending capacity using our help documentation to model your specific needs.
"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
One important note: We require an external warmup tool unless you're on the Done-for-You package. Factor that into your TCO calculation. Our warmup guide explains the process.
2. Setup velocity and DNS automation
Manual DNS configuration is the silent killer of agency productivity. Here's what most agencies don't calculate when evaluating infrastructure:
Time per domain (manual): Varies by technical expertise, typically 10-20 minutes for SPF, DKIM, DMARC records
50 domains: Potentially 8-16+ hours of cumulative work
DNS propagation: Up to 48 hours waiting time
Troubleshooting: Additional hours when records fail validation
That's significant time monthly just managing DNS, time that could go toward client calls, campaign optimization, or new business development. According to Cloudflare's DNS documentation, most DNS changes take effect within an hour but could take up to 48 hours to update globally.
Automated DNS configuration eliminates this entirely. Watch the Cold Email Setup: SPF, DKIM, and DMARC (2 minute setup for 10+ inboxes) video to see the actual process.
The step-by-step InfraMail Setup Tutorial from Shivam Gupta walks through the complete workflow.
3. IP reputation control (Dedicated vs. Shared)
Think of shared IP pools like a carpool lane where you're affected by other drivers. One aggressive sender spamming the pool gets the entire IP range flagged. Your campaigns suffer because of behavior you can't control.
The Dedicated IP vs Shared IP Pools video explains this in detail, but here's the core difference:
Reputation Element | Shared IP | Dedicated IP |
|---|---|---|
Reputation control | Pooled with other senders | You own it entirely |
"Bad neighbor" risk | High | None |
Warmup required | Sometimes pre-warmed | Yes, from cold |
Best for | Low volume, quick start | Scale, consistent campaigns |
One critical note: dedicated IPs require a 2-4 week warmup period because they start with zero sending history. You're building reputation from scratch, which takes time but gives you complete control. Shared IPs may offer faster deployment but you inherit whatever reputation the pool already has, good or bad.
We provide 1 dedicated US-based IP on the Unlimited Plan ($129/month) and 3 dedicated IPs on the Agency Pack ($327/month).
4. Vendor stability and support
The cold email infrastructure space is new. Many vendors launched in 2023-2024 with limited track records. Here's what to verify:
Infrastructure backing: We run on Microsoft's cloud platform. This matters for reliability and enterprise-grade uptime.
Support responsiveness: Real people, not chatbots. We offer priority support 16 hours daily.
Customer base: We serve 2,000+ customers as of January 2026, with 38 5-star reviews on Trustpilot (see all reviews: https://www.trustpilot.com/review/inframail.io).
Deliverability testing: We consistently test deliverability using Mail-Tester and inbox placement tools. Independent testing via GMass confirms strong inbox rates.
"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. I've had nothing but excellent service and the team showing a commitment to help every time I've contacted support." - Verified user review of Inframail
For answers to common setup questions, check our Frequently Asked Questions.
Provider comparison: Inframail vs. Maildoso vs. Google Workspace
Here's the straight comparison based on the criteria that matter:
Factor | Inframail | Maildoso | Google Workspace |
|---|---|---|---|
Setup speed | Under 10 minutes (automated) | 10-15 minutes | Variable (manual DNS) |
Cost (50 inboxes) | ~$185-235/month | ~$115-137/month | $350-420/month |
IP type | Dedicated (1-3 IPs) | Shared pool | N/A |
Warmup included | No (external required) | No | N/A |
Infrastructure | Microsoft-backed | Custom SMTP | Google Cloud |
Reviews | 30+ Trustpilot | 141 G2 reviews | 46,881 G2 reviews |
When Maildoso makes sense:
You're running fewer than 30 inboxes and staying at that scale
You're comfortable with shared IP reputation risk and accept that one bad neighbor can tank your campaigns
Lower upfront costs matter more than long-term margin protection
When Google Workspace makes sense:
You need native Google integration for regular business email
You're running fewer than 15 cold email inboxes and not planning to scale
Budget is secondary to UI familiarity and you can absorb $350-420/month recurring costs
When Inframail makes sense:
You're scaling past 50 inboxes and need costs to stop growing linearly with volume
You want reputation isolation via dedicated IPs so your deliverability isn't hostage to other senders' behavior
Flat-rate pricing protects your margins as you grow, adding 50 more inboxes costs you $0 in platform fees
You value automated DNS configuration that reclaims hours for client-facing work
You need Microsoft-backed infrastructure with enterprise-grade uptime
Watch I Built the Cheapest Cold Email Infrastructure (It Prints Money) for an independent perspective on cost optimization.
"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
The Mailreef vs Mailscale vs Inframail comparison video provides additional context on how dedicated servers differ from shared pools.
How to migrate 50 domains without pausing campaigns
Migration doesn't require downtime. Here's the process:
Export your contact lists and campaign data from your current sending platform. Keep your sequences intact.
Purchase domains through Inframail or transfer existing ones. New domain registration costs vary by TLD ($5-16/year). If you're transferring domains you already own, the transfer fee is $5 per domain and takes 24 hours. You can bring domains over from GoDaddy, Google, Namecheap, or any other registrar.
Let DNS auto-configure. As soon as you start creating email accounts, we automatically add all SPF, DKIM, and DMARC records. You can watch the progress in real-time. The How to Create Unlimited Cold Email Inboxes INSTANTLY demo shows this process.
Export credentials to your sending platform. After inbox creation, download a clean spreadsheet with IMAP/SMTP credentials. Our CSV export guide explains the export process. Import directly to Instantly, Smartlead, or your preferred tool.
Warm the new inboxes. Dedicated IPs start with zero sending history, so you'll spend 2-4 weeks gradually increasing volume to build ESP trust. This is the trade-off for reputation isolation: you control the warmup, but you must invest the time. Use an external warmup service during this period. Our warmup guide walks through the schedule.
The How to send 1000+ Cold Emails Per Day using Inframail (4 min setup) video demonstrates the complete workflow from domain purchase to inbox creation.
For platform compatibility, review our documentation on What email platforms work with Inframail.
Common pitfalls that destroy deliverability
I've seen agencies make these mistakes repeatedly:
Pitfall 1: Ignoring total cost of ownership
Vendors advertise the platform fee, not the real monthly cost. Always calculate: platform + domains + warmup + sending tool. A headline price of $99/month becomes $150+ when you add external services.
Pitfall 2: Trusting "unlimited" claims on shared IPs
"Unlimited inboxes" on a shared IP pool means unlimited exposure to bad neighbors. One aggressive sender tanks the entire pool's reputation. Your campaigns suffer for behavior you didn't cause and can't control.
Pitfall 3: Skipping warmup on dedicated IPs
Dedicated IPs start with zero reputation. Without proper warmup, ESPs treat your sends as suspicious. Budget 2-4 weeks of gradual volume increase before running full campaigns. The video 3 Tips to AVOID the SPAM Folder When Sending Cold Emails covers this process.
Pitfall 4: Manual DNS across 50+ domains
Every hour you spend in DNS panels is an hour not spent on sales calls or client strategy. At 50 domains, manual configuration can consume an entire workday or more. That's time you could spend closing deals or optimizing campaigns.
"I've been using Inframail for a couple of months and the experience has been really good. I can set-up inboxes in 5mins while saving money on Google Workspace subscriptions and benefit from great deliverability." - Verified user review of Inframail
Watch I Sent 10,000+ Cold Emails... Here's How I Avoided the Spam Folder for practical deliverability tactics.
Choosing the right stack for your scale
Your infrastructure decision depends on your current volume and growth trajectory:
Under 15 inboxes: Google Workspace works if you need native Google integration and aren't planning to scale. The per-seat cost won't kill your margins yet. But if you're planning to grow past 20 inboxes in the next 6-12 months, starting with flat-rate infrastructure now saves you a future migration.
15-50 inboxes: Transition zone. Per-inbox costs start compounding, but you might tolerate it for simplicity. Consider a pilot with flat-rate infrastructure.
50+ inboxes: Flat-rate infrastructure becomes essential for healthy margins. The math doesn't work otherwise. Dedicated IPs provide reputation control at this scale.
100+ inboxes: You need Agency-level infrastructure (multiple dedicated IPs) and likely a sending platform with built-in warmup or a dedicated warmup tool budget.
"Where do I start! I am blown away by Inframail's customer service, primarily... The platform is growing and even though it is not perfect—yet (very minor things here and there), what you get is exponentially huge and worth every dollar." - Verified user review of Inframail
The My Full Cold Email Setup And Strategy (Instantly + Inframail) video shows a complete agency stack in action.
Sign up to Inframail and get started today.
Frequently asked questions
What is the difference between shared and dedicated IPs?
Shared IPs pool reputation across multiple senders, meaning one bad actor can damage deliverability for everyone. Dedicated IPs isolate your reputation so your sending behavior alone determines ESP trust.
Do I need to warm up Inframail inboxes?
Yes. Dedicated IPs start with zero reputation. Plan for 2-4 weeks of gradual volume increase using an external warmup tool before running full campaigns. Alternatively, our Done-for-You package includes warmup management.
Can I use Inframail inboxes for regular work email?
No. We designed Inframail specifically for cold outreach. Mixing cold email with regular business communication risks your primary domain's reputation.
How long does DNS configuration take with Inframail?
Automated configuration completes in minutes. Users consistently report setup times under 10 minutes for multiple inboxes.
What sending platforms integrate with Inframail?
We export IMAP/SMTP credentials via CSV for import into Instantly, Smartlead, Lemlist, and other major sending tools.
Key terms glossary
SPF (Sender Policy Framework): An authentication protocol that lists IP addresses authorized to send email on behalf of your domain. According to Cloudflare's SPF documentation, think of it as a guest list specifying which servers can send mail as you.
DKIM (DomainKeys Identified Mail): A digital signature that proves an email hasn't been modified in transit and came from the claimed sender. It works like a tamper-proof seal on your messages.
DMARC (Domain-based Message Authentication, Reporting & Conformance): A policy that tells receiving servers what to do when SPF or DKIM checks fail. It's the enforcement layer that instructs ESPs to deliver, quarantine, or reject unauthenticated emails.
Dedicated IP: An IP address assigned exclusively to your account. Your sending behavior alone determines reputation, with no "bad neighbor" risk from other senders.
Flat-rate pricing: A fixed monthly fee regardless of inbox count, as opposed to per-seat pricing that scales linearly with volume.
