Comparison
Jan 7, 2026
CEO and co-founder
Best Cold Email Infrastructure for Agencies (2025 Guide)
Why the "Google Workspace for everything" model breaks at scale
The linear cost trap catches most agency founders around the 30-50 inbox mark. At $7/user monthly on annual Business Starter plans (or $8.40/user on monthly billing), Google Workspace is fine for 5 users. But scale to 200 inboxes and you are paying $1,400-1,680/month in infrastructure costs alone.
Here is how the math plays out:
Inbox Count | Google Workspace Monthly | Google Workspace Annual |
|---|---|---|
20 inboxes | $140-168 | $1,680-2,016 |
50 inboxes | $350-420 | $4,200-5,040 |
100 inboxes | $700-840 | $8,400-10,080 |
200 inboxes | $1,400-1,680 | $16,800-20,160 |
Beyond cost, the admin bottleneck compounds. Managing 50+ separate admin consoles means logging into Namecheap, GoDaddy, or Cloudflare to manually create SPF, DKIM, and DMARC records for each domain. Each domain takes 15-30 minutes to configure properly. For 50 domains, that is 12.5-25 hours of manual DNS work before you send a single email.
Watch the Ultimate Cold Email Infrastructure Guide for 2025 for a complete breakdown of infrastructure requirements.
5 critical factors for evaluating cold email infrastructure
Before comparing specific platforms, you need a framework for evaluation. These five factors determine whether an infrastructure choice protects or destroys your agency margins.
1. Total cost of ownership (TCO)
TCO is not just the platform fee. It includes:
Platform subscription: The base monthly or annual cost
Domain costs: Purchase price ($9-16/year) plus renewal fees
Warmup tools: External services like Warmbox at $15-50/month per inbox if not included
Sending platform: Instantly at $37/month or Smartlead at $39/month
Most agencies focus only on platform pricing and miss the warmup cost multiplier. According to Mailreach's pricing analysis, warmup tools can add $25/inbox/month at standard rates. For 50 inboxes, that is an extra $1,250/month.
2. Setup automation
Can you spin up 10 domains in 5 minutes, or does it take 5 hours? This distinction separates profitable agencies from those trapped in technical busywork.
Inframail users report setting up 10 inboxes in 2 minutes with automated SPF, DKIM, and DMARC configuration. Manual DNS configuration through Google Workspace requires accessing DNS panels, creating individual records, waiting 24-48 hours for propagation, and testing with Mail-Tester.
Our help center guide on email sending capacity walks through the full calculation process.
3. IP reputation (dedicated vs. shared)
This is where most agencies make costly mistakes. Shared IP pools mean you share reputation with other senders. If another sender on your shared IP starts spamming, your deliverability tanks.
According to Elementor's IP comparison, the "bad neighbor" effect occurs when another site on your shared IP sends spam or hosts malware. The entire IP gets blacklisted, impacting your email deliverability even if you follow best practices.
Dedicated IPs mean your email reputation is 100% your own. Only your behavior affects your sender score.
4. Platform stability
Infrastructure built on Microsoft Azure, AWS, or GCP provides enterprise-grade reliability. Custom servers from unknown providers introduce risk. Several top providers use enterprise infrastructure layers from major cloud providers, provisioning pre-warmed, enterprise-grade IP pools.
5. Support and reliability
Response times matter when deliverability drops 25% overnight and clients threaten cancellation Monday morning. According to Trustpilot reviews of Mailscale, support quality varies significantly for infrastructure providers. Some users report responsive help while others faced weeks-long delays on critical warmup issues.
Top cold email infrastructure providers compared
Here is how the major platforms stack up across the factors that matter most:
Provider | Pricing Model | IP Type | Backend | Native Warmup | Best For |
|---|---|---|---|---|---|
Inframail | Flat-rate $129/mo + domains | Dedicated (1-3 IPs) | Microsoft Azure | No | 50+ domain agencies |
Mailscale | Tiered ($79-249/mo) + domains | Shared pool | AWS | No | IP rotation focus. |
Maildoso | Per-inbox ($100+/mo) + domains | Shared with rotation | Not disclosed | No | IP rotation focus |
Mailforge | Per-slot (~$3/mailbox) + domains | Shared pool | Not disclosed | Yes | Budget-conscious startups |
Google Workspace | Per-seat ($7-8.40/mo) + domains | Google IPs | Google Cloud | N/A | Primary domains only |
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.
Inframail: best for high-volume agencies seeking flat-rate margins
Inframail runs on Microsoft-backed servers with dedicated US-based IPs. The Unlimited Plan costs $129/month ($103.20/month on annual billing) and includes 1 dedicated IP with unlimited inbox creation.
Key features:
Automated DNS setup: SPF, DKIM, and DMARC records configured in seconds
Unlimited inboxes: No per-seat charges regardless of volume
Dedicated IPs: 1 IP on Unlimited Plan, 3 IPs on Agency Pack ($249/month)
Domain management: Purchase domains at $9-16/year or transfer existing domains for $5 each
Watch our 2-minute SPF, DKIM, and DMARC setup tutorial showing the automated configuration process for 10+ inboxes.
Limitations to consider:
Microsoft-only mailboxes: No Google Workspace account creation. If clients require Gmail, you need a separate solution.
No native warmup: External warmup tools required
Domain setup rate limits: No limits. Unlimited domain setups per day.
Best for: Agencies running 50+ domains who want to cap infrastructure costs while maintaining dedicated IP control. The Inframail setup tutorial demonstrates the full workflow.
Mailscale review: features, pricing, and support
Mailscale offers tiered pricing based on inbox count. According to Woodpecker's 2025 review, plans include:
Solopreneur: $79/month ($63/month annually) for up to 15 email accounts
Business: $119/month ($95/month annually) for up to 50 email accounts
Enterprise: $249/month ($199/month annually) for up to 200 email accounts
All plans include automated DNS setup for DKIM, DMARC, and SPF records. The platform handles technical configuration to improve deliverability and prevent spam flagging.
Support quality: Mixed reviews across platforms. Affiliate Weapons notes that consumers value excellent customer support with responsive issue resolution. However, Trustpilot feedback shows some users experienced warmup issues lasting weeks with delayed support responses.
Verdict: Mailscale works well for agencies but pricing tiers punish growth compared to flat-rate options. Scaling from 50 to 200 inboxes jumps your bill from $119 to $249/month. The same scale on Inframail stays at $129/month.
Maildoso: best for agencies prioritizing shared IP rotation
Maildoso focuses on shared IP pools with heavy rotation. According to Saleshandy's comparison, the base plan costs $100/month for 8 domains and 32 mailboxes, including SPF, DKIM, DMARC setup and daily inbox placement checks.
Pricing tiers:
Base: $100/month for 32 mailboxes (8 domains)
Mid-tier: $166/month for 68 mailboxes (17 domains)
Enterprise: $733/month for 400 mailboxes (100 domains)
Key consideration: Shared IPs mean your reputation depends on other senders in the pool. Maildoso rotates IPs to mitigate this, sending from warm IPs with the strongest deliverability in the available pool. But you sacrifice the control of dedicated infrastructure.
Mailforge: best for agencies needing rapid shared IP setup
Mailforge uses a slot-based pricing system. Each slot represents capacity to create one mailbox. According to TrulyInbox's infrastructure guide, pricing ranges from $3/mailbox/month down to $1.67/month for bulk users.
Pricing structure:
Minimum purchase: 10 slots
Monthly billing: $150/month for 10 slots ($15/mailbox)
Annual billing: $130/month for 10 slots ($13/mailbox)
Bulk discounts: Can drop to $1.67/mailbox at volume
Native warmup included: Mailforge warms domains automatically in the background.
Trade-off: Mailforge operates using a shared IP pool, distributing mailbox accounts among millions of businesses. This shared infrastructure means you do not control your sending reputation independently.
Google Workspace: best for low-volume, high-compliance campaigns
Google Workspace remains the gold standard for deliverability. Native Gmail infrastructure provides the highest inbox placement rates. But the economics only work for primary business domains or very low-volume operations.
Current pricing: $7/user/month on annual plans, $8.40/user/month on monthly billing according to Name.com's pricing guide.
When to use Google Workspace:
Primary agency domains requiring professional email
High-value ABM campaigns needing maximum deliverability
Compliance-heavy industries requiring G Suite integrations
When to avoid:
Cold email at scale (50+ domains)
Budget-constrained operations
Rapid domain rotation requirements
The economics of scale: TCO analysis for 50, 100, and 200 inboxes
Here is the math that matters. I calculated total cost of ownership across three scale scenarios, including platform fees, estimated domain costs, and warmup tool requirements.
Scenario A: 50 inboxes (one year)
Cost Component | Google Workspace | Inframail + Warmup | Mailscale |
|---|---|---|---|
Platform fee | $4,200 ($7×50×12) | $1,548 ($129×12) | $1,428 ($119×12) |
Domain costs | N/A (included) | ~$408 (~$34/mo amortized) | Included |
Warmup tool | N/A | ~$6,000-9,000 ($10-15×50×12) | Included |
Annual Total | $4,200 | $7,956-10,956 | $1,428 |
Important caveat: The warmup calculation assumes $10-15/inbox/month with bulk discounts. At standard Warmbox or Mailreach pricing ($25/inbox), external warmup adds $15,000/year for 50 inboxes. However, Instantly's warmup comparison shows budget alternatives starting at $9/month or even free options like Mailflow for up to 100 inboxes.
Inframail without warmup cost (if using free warmup tools):
Platform | Annual Cost | vs. Google Savings |
|---|---|---|
Google Workspace (50 inboxes) | $4,200 | — |
Inframail ($129/mo + domains) | $1,596 | $2,604/year |
Mailscale Business | $1,428 | $2,772/year |
Scenario B: 200 inboxes (one year)
Cost Component | Google Workspace | Inframail | Mailscale Enterprise |
|---|---|---|---|
Platform fee | $16,800 ($7×200×12) | $1,548 ($129×12) | $2,988 ($249×12) |
Domain costs | N/A | ~$800 (40 domains × $20) | Included |
Platform + Domains | $16,800 | $1,988 | $2,988 |
Annual Savings vs. Google | — | $14,812 | $13,812 |
At 200 inboxes, flat-rate infrastructure saves your agency $13,000-15,000 annually on platform costs alone before warmup considerations.
Watch our case study video showing how Jackson Williams books 6 calls per day sending cold emails with Inframail infrastructure.
Decision matrix: which infrastructure fits your agency stage
Infrastructure choice depends on client count, technical comfort, and margin sensitivity. Here is how to decide:
Starter stage (1-5 clients)
Recommendation: Stick with Google Workspace
At this stage, you are managing 10-25 inboxes maximum. Google Workspace costs $70-175/month. The complexity of migrating infrastructure and learning new platforms is not worth the savings yet. Focus on landing more clients.
Monthly infrastructure ceiling: Under $200
Growth stage (6-15 clients)
Recommendation: Switch to flat-rate infrastructure
At 30-75 inboxes, Google Workspace bills reach $210-525/month. Flat-rate platforms like Inframail at $129/month create immediate margin expansion. The $100-400/month savings can fund a part-time VA or junior hire.
Action item: Calculate your current per-inbox cost. If you are paying more than $1/inbox/month on infrastructure alone, migration makes financial sense.
Review the domain transfer step-by-step guide for migration planning.
Monthly infrastructure ceiling: Under $500
Scale stage (15+ clients)
Recommendation: Inframail or hybrid approach
At this stage, you are managing 75-200+ inboxes across multiple clients. The math becomes undeniable:
Google Workspace at 150 inboxes: $1,050-1,260/month
Inframail at 150 inboxes: $129/month + domain costs (~$50/month) = ~$150/month
Hybrid strategy: Use Inframail for volume cold email domains and keep Google Workspace for primary agency domains requiring G Suite integrations.
See how one Inframail user signed a $50,000 whale client with cold email using this approach.
Frequently asked questions about cold email infrastructure
What is the difference between dedicated and shared IPs?
Dedicated IPs are used only for your emails. Your behavior alone determines reputation. Shared IPs are used by multiple senders. If another sender spams, your deliverability suffers. According to Instantly's IP comparison, dedicated IPs offer control and predictability while shared pools provide immediate sending capability with exposure to other senders.
Do I still need an external warmup tool with Inframail?
Yes. Inframail does not include native warmup. You need external services like Warmbox, Mailreach, or Instantly for inbox warming. Our warmup migration guide explains the process. Mailscale and Maildoso include native warmup.
Can I use these inboxes with Instantly or Smartlead?
Yes. All major cold email infrastructure providers export IMAP/SMTP credentials in CSV format. Import directly into Instantly, Smartlead, or any other sending platform. See our email platform compatibility guide.
How long does DNS propagation take with automated tools?
Inframail users report SPF, DKIM, and DMARC configuration completing in seconds through the platform. Propagation across global DNS servers is instant. The automation eliminates manual record creation.
What is a healthy inbox placement rate for cold email?
According to Validity's 2024 Email Deliverability Benchmark, the global inbox placement average sits around 84% with roughly one in six emails never reaching the inbox. Industries like SaaS and tech achieve deliverability rates near 99% when following best practices.
How do I know if my campaign emails are going to spam?
Monitor bounce rates, open rates, and reply rates. Sudden drops indicate deliverability problems. Use tools like Mail-Tester (aim for 8.5+/10) and GMass inbox rate testing. Our campaign health metrics guide provides specific thresholds.
Key terminology for agency founders
SPF (Sender Policy Framework): Authentication protocol that tells receiving servers which IP addresses can send email for your domain. Prevents spoofing and improves deliverability. According to Breakcold's technical guide, SPF helps email servers verify trusted sources.
DKIM (DomainKeys Identified Mail): Cryptographic signature attached to outgoing emails proving the message was not altered in transit. DKIM prevents impersonation and phishing attacks using your domain.
DMARC (Domain-based Message Authentication Reporting and Conformance): Policy layer that tells receiving servers what to do when SPF or DKIM checks fail. DMARC is the final verification test preventing spoofing.
Inbox Placement Rate: Percentage of emails that reach the recipient's primary inbox rather than spam or promotions folders. Industry benchmark is 84% according to Security Boulevard's 2025 analysis.
TCO (Total Cost of Ownership): Complete annual cost including platform fees, domain purchases, warmup tools, and sending platform subscriptions. TCO provides accurate comparison beyond headline pricing.
Dedicated IP: IP address used exclusively by your organization. Your sending behavior alone affects reputation. Inframail includes 1-3 dedicated IPs depending on plan.
Shared IP Pool: Multiple senders using the same IP addresses. Reputation is affected by all users in the pool. Lower cost but higher risk from "noisy neighbor" behavior.
