Comparison
Feb 12, 2026
CEO and co-founder
Cold Email Service Providers: Complete Guide to Infrastructure, Pricing & Deliverability
What is a cold email service provider?
A cold email service provider is a specialized infrastructure platform designed for high-volume outbound email campaigns. These providers differ from standard business email services (Google Workspace, Microsoft 365) by offering bulk inbox creation, automated DNS authentication, and infrastructure optimized for cold outreach rather than internal team communication.
The category emerged because you can't efficiently run 50-200 domains across multiple clients on platforms built for internal business email. Google Workspace works great for a 10-person company needing business email. It becomes expensive and operationally complex when you need 100 inboxes with proper SPF, DKIM, and DMARC records configured across 50 domains.
Service provider vs. infrastructure: understanding the difference
Cold email infrastructure and cold email sending platforms serve different functions in your outreach stack:
Infrastructure providers (Inframail, Google Workspace, Microsoft 365) handle:
Domain hosting and management
Mailbox/inbox creation
DNS record configuration (SPF, DKIM, DMARC)
IP address provisioning
SMTP/IMAP credentials
Sending platforms (Instantly, Smartlead, Lemlist) handle:
Campaign sequencing and automation
Inbox rotation across accounts
Follow-up scheduling
Analytics and reporting
A/B testing
Think of infrastructure as the foundation and the sending platform as the house built on top. You need both, but switching one doesn't require switching the other. We cover integration options in detail in our guide on email platforms that work with Inframail.
Recent authentication requirements that changed the market
In October 2023, Google and Yahoo announced new requirements for bulk senders taking effect in February 2024. These requirements made proper email authentication mandatory rather than optional.
The key requirements include:
DMARC policy implementation with minimum p=none
SPF and DKIM authentication for all outbound mail
One-click unsubscribe for marketing messages
Spam complaint rates below 0.3%
For agencies, these changes mean infrastructure quality matters more than ever. Sending from domains without proper authentication results in immediate filtering. According to Google's bulk sender guidelines, senders exceeding 5,000 emails per day must meet all requirements or face deliverability penalties.
Core components of cold email infrastructure
Understanding the technical components helps you evaluate what different providers actually offer versus what they claim in marketing.
Domain management and reputation isolation
Cold email campaigns require separate domains from your primary business domain. If a cold outreach domain gets flagged or blacklisted, you don't want that affecting your main company email.
Effective domain management includes:
Bulk domain purchasing at reasonable rates ($5-16/year per domain)
Centralized domain dashboard for monitoring health
Domain rotation capabilities to spread sending load
Redirect configuration to protect link reputation
We cover domain strategy in depth in our ultimate guide to custom domains. Many agencies find success with 3-5 domains per client and 2-3 inboxes per domain as a starting baseline, though optimal ratios vary by campaign volume and industry.
DNS authentication protocols (SPF, DKIM, DMARC)
These three protocols work together to verify your emails are legitimate. Here's what you need to verify in your DNS panel and why each record matters for inbox placement:
Protocol | Function | What It Proves |
|---|---|---|
SPF | Specifies authorized sending servers | Email came from an approved source |
DKIM | Adds cryptographic signature | Email wasn't modified in transit |
DMARC | Defines handling policy | Tells receivers what to do if checks fail |
According to Cloudflare's technical documentation, these protocols work together to prevent email spoofing and improve deliverability.
Manual configuration requires logging into your DNS provider for each domain, adding TXT records, waiting for propagation, and testing with tools like Mail-Tester. DNS propagation typically takes a few hours but can extend to 24-48 hours for full global propagation according to GoDaddy's documentation. For agencies managing dozens of domains, this manual process becomes a significant time investment.
Watch our SPF, DKIM, and DMARC setup video to see how automated configuration works in practice.
Inbox provisioning and warm-up
Creating inboxes at scale involves:
Account creation with unique credentials
SMTP/IMAP configuration for sending platform integration
Warm-up to establish sender reputation before full-volume campaigns
One important note on warm-up: Inframail provides infrastructure but requires external warm-up tools for standard plans. Sending platforms like Instantly ($37/month with unlimited warm-up) or Smartlead ($39/month with unlimited warm-up) handle this step. We walk through the process in our warm-up guide for new Inframail users.
Why Google Workspace destroys margins as you scale
Google Workspace and Microsoft 365 are excellent products for their intended purpose. But that purpose isn't running cold email campaigns at scale.
The hidden costs of per-seat pricing models
Let's run the numbers for Google Workspace Business Starter at current pricing of $8.40/user/month on monthly billing:
Inbox Count | Monthly Cost | Annual Cost |
|---|---|---|
25 inboxes | $210 | $2,520 |
50 inboxes | $420 | $5,040 |
100 inboxes | $840 | $10,080 |
200 inboxes | $1,680 | $20,160 |
Now compare that to flat-rate infrastructure where cost stays constant regardless of inbox count:
Inbox Count | Flat-Rate Platform | Est. Domain Costs | Monthly Total | Annual Savings vs. Google |
|---|---|---|---|---|
25 inboxes | $129 | ~$34.25 | ~$163.25 | $561/year |
50 inboxes | $129 | ~$68.50 | ~$197.50 | $2,670/year |
100 inboxes | $129 | ~$137.00 | ~$266.00 | $6,888/year |
200 inboxes | $129 | ~$274.00 | ~$403.00 | $15,324/year |
Domain costs estimated at $16.44/domain/year amortized monthly. Actual costs vary from $5-16/domain depending on TLD and registrar.
The savings compound as you scale. At 50 inboxes, you save approximately $222.50/month. At 200 inboxes, you save approximately $1,277/month before accounting for warmup tool costs.
Dedicated infrastructure vs. general ESPs
Beyond pricing, general ESPs lack features cold email agencies need:
What Google Workspace doesn't offer:
Bulk inbox creation tools designed for cold email scale
Automated DNS configuration for multiple domains
Dedicated IP provisioning (you send from Google's shared pools)
Centralized cold email management dashboard
Domain health monitoring for outreach campaigns
What dedicated infrastructure provides:
Unlimited inbox creation with a few clicks
Auto-configured DNS records in seconds
Dedicated IPs that isolate your reputation
CSV export for sending platform integration
Blacklist monitoring and delisting automation
"InfraMail makes it remarkably easy to purchase domains, configure them correctly, create inboxes, and initiate warm-up immediately. The level of automation is exceptional and clearly designed for serious operators." - Verified user review of Inframail
We explain why the dedicated vs. shared IP distinction matters in our dedicated IP vs. shared IP pools video.
How to evaluate cold email service providers
The vendor marketing all sounds similar. Here's what to actually look for.
Total Cost of Ownership (TCO) analysis
Headline pricing tells you almost nothing. True cost per inbox includes:
Platform fee (monthly subscription)
Domain costs ($5-16/year per domain, amortized monthly)
Warm-up tools ($15-50/month per inbox for external services, or included with sending platform)
Sending platform ($37-77/month for Instantly or Smartlead)
Here's a realistic TCO comparison for 50 inboxes:
Cost Component | Google Workspace | Inframail |
|---|---|---|
Platform fee | $420/mo | $129/mo |
Domains (50) | ~$68.50/mo amortized | ~$68.50/mo amortized |
Warm-up | External | External |
Infrastructure Total | ~$488.50/mo | ~$197.50/mo |
The numbers shift at different scales. Calculate your specific TCO using our sending capacity calculator.
Setup time savings and automation
Time has a cost. Manual DNS configuration requires logging into registrar panels, creating TXT records, waiting for propagation, and testing each domain. For agencies managing 50+ domains, this work can consume significant weekly hours that could go toward client acquisition or campaign optimization.
Automated infrastructure changes the equation:
"The setup is ridiculously fast. SPF, DKIM, DMARC, forwarding - all handled in literally seconds without me having to dig through docs or guess what records to add." - Verified user review of Inframail
For a complete walkthrough, watch the Inframail setup tutorial showing the actual process from domain to live inbox.
Deliverability performance metrics and transparency
Ask potential vendors for:
Mail-Tester scores (9+/10 indicates properly configured infrastructure)
Inbox placement rates with testing methodology disclosed
Sample sizes for any deliverability claims
IP type (dedicated vs. shared pools)
Shared IP pools create "noisy neighbor" risk. If someone else sending from your IP range gets flagged for spam, your deliverability suffers. Dedicated IPs isolate your reputation so your sending behavior alone determines ESP trust.
We break down the metrics that matter in our guide to identifying spam issues.
Contract flexibility and scaling terms
For agencies with fluctuating client counts, contract structure matters:
Red flags when evaluating providers:
Forced annual commitments: No ability to test with real campaigns before long-term commitment
Quarterly billing minimums: Limits flexibility for agencies with fluctuating client counts
Hidden cancellation fees: Unexpected charges when scaling down or switching
Setup charges buried in checkout: Surprise costs that destroy budget planning
Green flags to look for:
Month-to-month options: Test before committing long-term
Pilot capability: Start with 10-20 domains to validate performance
Transparent pricing: Costs visible on website without demo calls
Clear scaling terms: Know what happens when you grow or shrink
"Unlimited inboxes on a flat price? That alone saves me hundreds every month compared to Google Workspace or similar." - Verified user review of Inframail
Top cold email service providers compared
Let me break down the major options in the market.
Inframail Inframail has 38 5-star reviews on Trustpilot.
Pricing: $129/month (Unlimited Plan) or $327/month (Agency Pack)
What you get:
Unlimited email inboxes on Microsoft infrastructure
1 dedicated US-based IP (Unlimited) or 3 IPs (Agency Pack)
Automated SPF, DKIM, DMARC configuration
Blacklist monitoring with auto-delisting requests
CSV export for Instantly/Smartlead integration
B2B contact database (545M+ contacts) on annual plans
What you don't get:
Built-in warm-up on standard plans (requires external tools)
Google Workspace option (Microsoft infrastructure only)
EU/APAC data residency (US-based IPs only)
"Their platform did in 10 minutes what would've taken me days to figure out. Maybe weeks. We're talking full infrastructure." - Verified user review of Inframail
Watch our Ultimate Cold Email Infrastructure Guide for the complete setup process.
Google Workspace / Microsoft 365
Pricing: $7-8.40/user/month for Google Workspace Business Starter depending on billing commitment. Microsoft 365 Business Basic starts at $6/user/month with price increases announced for mid-2026.
What you get:
Native platform trust and deliverability
Enterprise features (calendar, drive, docs)
Strong admin console
Industry-standard infrastructure
What you don't get:
Bulk inbox creation tools for cold email
Automated DNS for outreach campaigns
Dedicated IP provisioning
Flat-rate pricing at scale
Google Workspace works well for companies needing business email with occasional outreach. It becomes expensive and operationally complex when managing 50+ cold email inboxes across multiple clients.
Shared IP pool providers
Some providers offer per-inbox pricing (typically $2-4/inbox/month) with shared IP infrastructure. While initial costs may appear lower, shared pools create risks:
Potential issues:
Reputation affected by other users on your IP range
Deliverability fluctuations outside your control
Domain and IP warming inconsistencies
Less predictable inbox placement rates
"Rock-solid infrastructure, sharp support, genuinely dependable." - Verified user review of Inframail
When evaluating any provider, ask specifically whether IPs are dedicated or shared. The answer significantly impacts long-term deliverability.
Managing infrastructure for agency growth
Picking the right provider is step one. Operating it efficiently requires some additional planning.
Handling multiple client domains
Best practices for multi-client management:
Isolate client infrastructure with separate domain groups
Document credential organization using consistent naming conventions
Monitor per-client deliverability to catch issues before clients notice
Establish rotation schedules to maintain domain health
We cover efficient workflows for bulk credentials in our CSV management guide.
When to switch from manual setup to automation
The tipping point for most agencies arrives around 20-30 inboxes. Signs you've reached it:
DNS configuration takes more than 3 hours weekly
You're spending more time on infrastructure than client strategy
Infrastructure costs exceed 25% of client billings
Adding new clients creates operational bottlenecks
"I can set-up inboxes in 5mins while saving money on Google Workspace subscriptions and benefit from great deliverability. All of my campaigns on Inframail are on a >10% reply rate, which is really good." - Verified user review of Inframail
Watch our guide to getting cold emails delivered to understand which infrastructure decisions impact placement rates.
Building your cold email infrastructure stack
Here's a practical implementation checklist:
Phase 1: Foundation (Week 1)
Audit current infrastructure costs (platform + domains + warmup + labor)
Calculate TCO per inbox at current and projected scale
Evaluate 2-3 providers against criteria above
Phase 2: Migration (Week 2-3)
Start with pilot batch of 10-20 domains
Configure DNS authentication and verify records
Connect to sending platform (Instantly, Smartlead)
Begin warm-up process
Phase 3: Optimization (Week 4+)
Monitor deliverability metrics across test campaigns
Validate inbox placement rates match expectations
Scale to full domain count once validated
Establish ongoing monitoring and maintenance routines
We provide step-by-step instructions in our guides on warming up email domains and cold email strategy.
Making the switch
The infrastructure decision comes down to simple math. At 50 inboxes, Google Workspace costs $420/month. Dedicated flat-rate infrastructure costs $129/month plus approximately $68.50 in domain costs. That's roughly $222.50/month in savings, or over $2,670/year.
Scale to 100 inboxes and your savings grow to approximately $574/month. At 200 inboxes, you save approximately $1,277/month on infrastructure alone.
Beyond cost, you gain time back. Instead of hours configuring DNS records manually, you spend minutes on setup and focus on what actually grows the business: client acquisition, campaign optimization, and building systems that scale.
"Best in class customer support. So affordable that it will make your unit economics work, even for lower ticket b2b businesses like ours." - Verified user review of Inframail
Sign up to Inframail and get started today.
Frequently asked questions
What is the difference between a shared and dedicated IP?
A dedicated IP sends only your email, so your reputation depends entirely on your behavior. Shared IPs are used by multiple senders, meaning other users' poor practices can damage your deliverability.
How much does cold email infrastructure cost per inbox?
Google Workspace costs $8.40/inbox/month on monthly billing. Flat-rate providers like Inframail cost $129/month total for unlimited inboxes plus domain costs, making per-inbox cost effectively $3.95 at 50 inboxes ($197.50 total) or $2.01 at 200 inboxes ($403 total including domains).
Do I need a separate warm-up tool?
Most infrastructure providers (including Inframail's standard plans) require external warm-up through sending platforms like Instantly or Smartlead. These typically cost $37-77/month with unlimited warm-up included.
How long does DNS configuration take manually vs. automated?
Manual configuration takes 10-20 minutes of active work per domain plus propagation time (typically a few hours, up to 48 hours for full global propagation). Automated platforms configure SPF, DKIM, and DMARC in seconds, though DNS propagation timing remains the same.
What inbox count justifies switching from Google Workspace?
At 15 inboxes, Google Workspace costs $126/month vs. $129 flat-rate (roughly breakeven before domain costs). At 30 inboxes ($252/month on Google), you save approximately $81.90/month. Above 50 inboxes, savings exceed $222/month.
Key terms glossary
SPF (Sender Policy Framework): A DNS record specifying which servers are authorized to send email on behalf of your domain. Receivers check SPF to verify the sending server is legitimate.
DKIM (DomainKeys Identified Mail): A cryptographic signature added to emails that proves the message wasn't altered in transit and came from the claimed domain.
DMARC (Domain-based Message Authentication, Reporting and Conformance): A policy telling receivers what to do when SPF or DKIM checks fail. Also enables reporting on authentication results.
Dedicated IP: An IP address used exclusively by your account for sending email. Your sending behavior alone determines the IP's reputation.
SMTP (Simple Mail Transfer Protocol): The protocol used to send email between servers. SMTP credentials connect your infrastructure to your sending platform.
IMAP (Internet Message Access Protocol): The protocol used to receive and manage email. IMAP credentials allow your sending platform to check replies and manage inbox state.
TCO (Total Cost of Ownership): The complete cost of a solution including platform fees, domain costs, warmup tools, and labor. More accurate than comparing headline pricing alone.
