Cold Email Infrastructure Cost: 2026 Pricing Comparison Across 11 Providers

We manage 650K+ inboxes across Microsoft 365, Google Workspace, and SMTP infrastructure for 1,500+ clients at MailDeck, maintaining 98% inbox placement. Based on Q1 2026 platform data.

Cold email infrastructure costs between $0.40 and $4.50 per inbox per month in 2026, depending on the provider and scale. We analyzed pricing across 11 providers at four scale levels: 100, 500, 1,000, and 5,000 inboxes. Here's what we found.

MailDeck comparison uses SMTP pricing. Google Workspace ($2.99-3.90/inbox) and Outlook tenant ($30-40/tenant) pricing also available.

The data shows that pricing models matter more than base rates. Providers using per-inbox pricing (like MailDeck SMTP at $0.50/inbox) become significantly cheaper at scale compared to other per-inbox providers (like Infraforge at $4.00/mailbox or Primeforge at $4.50/mailbox).

Methodology: How We Collected This Data

We collected pricing data from public pricing pages of 11 cold email infrastructure providers in March 2026. Here's our methodology:

Data collection:

• All prices taken from official pricing pages (accessed March 16, 2026)
• Monthly billing rates used (not annual discounts)
• Prices converted to USD where applicable

Calculations:

• Cost per inbox calculated at four scale levels: 100, 500, 1,000, and 5,000 inboxes
• For MailDeck: used SMTP per-inbox pricing tiers
• For tiered providers: calculated based on published tier structures
• Providers with unpublished pricing marked as "Contact for pricing"

What we measured:

• Total monthly cost at each scale level
• Cost per inbox at each scale level
• Infrastructure type (Microsoft 365, Google Workspace, private SMTP, or shared IP)

Limitations:

• Some providers offer custom discounts not reflected in public pricing
• Setup fees and domain costs not included in base comparisons
• Prices may change - check provider websites for current rates

Quick Summary: Cost Per Inbox Across All Providers

This table shows cost per inbox at four scale levels, sorted by cost at 1,000 inboxes (lowest to highest).

Key finding: At 1,000 inboxes, the cheapest provider (MailDeck SMTP at $500/month) costs 10x less than the most expensive (Primeforge at $4,500/month). Many providers require custom quotes at this scale.

Pricing sources: MailDeck | Maildoso | Infraforge | Mailforge | Mailscale | Mailin | Zapmail | Primeforge | Premium Inboxes. Prices verified March 2026.

Infrastructure Providers Compared: Pricing With Dedicated and Agency Support

Price per inbox only tells part of the story once you're managing infrastructure for multiple clients. Agencies running campaigns across several accounts need to compare email infrastructure providers with dedicated support, not just the lowest per-inbox rate, because a cheap plan with no account-level support turns into hours of DNS troubleshooting per client per month.

The table below adds a support column to the same 11-provider set, based on what each provider publishes about account-level and agency support as of Q3 2026.

Analysis: Of the 9 providers with published pricing, MailDeck is the only one that documents what agency/dedicated support is actually bundled into which plan tier, rather than leaving it behind a "contact us" quote. Diversified Stack clients get a named account contact and automated domain replacement on top of the DNS/auth setup, which matters most for agencies juggling multiple client domains at once. For a closer look at running infrastructure across many client accounts at this scale, see Agency Inbox Management, which covers managing 500+ inboxes across multiple clients.

Detailed Breakdown by Scale

100 Inboxes: Starting Out ($50-$500/month)

At 100 inboxes, most teams are testing cold email or running small campaigns.

*Tiered providers may not offer exactly 100 inboxes. Prices shown for closest available plan.

Analysis: At this scale, MailDeck SMTP at $50/month for 100 inboxes is the cheapest option. For smaller needs, Mailscale's 50-inbox plan at $119/month or Maildoso's 70-inbox plan at $158/month are alternatives. MailDeck also requires 48-hour setup time vs instant access at most per-inbox providers.

500 Inboxes: Growing Team ($250-$2,250/month)

At 500 inboxes, pricing models start to diverge significantly.

*Maildoso pricing estimated based on 300-inbox plan rate.

Analysis: MailDeck SMTP pricing becomes advantageous at this scale. MailDeck costs $250/month vs. Primeforge at $2,250/month - a 9x difference. MailDeck also offers Google Workspace ($2.99-3.90/inbox) and Outlook tenants ($30-40/tenant) for teams needing those providers.

1,000 Inboxes: Agency Scale ($500-$4,500/month)

This is the critical inflection point where pricing model choice determines thousands in monthly costs.

Annual savings comparison (vs. industry average of $3,000/month):

• MailDeck SMTP: Saves $30,000/year
• Mailin: Saves $18,120/year
• Mailforge/Premium Inboxes: Average baseline
• Infraforge: Costs $12,000/year more
• Primeforge: Costs $18,000/year more

Analysis: At 1,000 inboxes, MailDeck SMTP ($0.50/inbox) delivers the lowest cost per inbox. The annual cost difference between cheapest (MailDeck: $6,000) and most expensive (Primeforge: $54,000) is $48,000. Keep in mind: MailDeck provides infrastructure only - you'll need a separate sequencer (Instantly, Smartlead, etc.) for campaign management.

5,000 Inboxes: Enterprise Scale ($2,500-$22,500/month)

At enterprise scale, infrastructure costs become a significant line item.

Annual cost comparison:

• MailDeck SMTP: $30,000
• Premium Inboxes: $168,000
• Primeforge: $270,000
• Difference (MailDeck vs Primeforge): $240,000/year

Analysis: At enterprise scale, per-inbox pricing becomes prohibitively expensive. A team using Primeforge at 5,000 inboxes pays $270,000/year vs. MailDeck SMTP at $30,000/year - 9x more. Trade-off: MailDeck's 48-hour provisioning time means you can't instantly spin up new inboxes during rapid scaling.

Pricing Models Explained: Per Inbox vs Per Domain vs Tiered

The data shows that pricing model matters more than the advertised rate. Here's how each model works:

Per Inbox Pricing

How it works: You pay a fixed rate for each mailbox. $3.00/inbox means 100 inboxes = $300, 1,000 inboxes = $3,000.

Providers using this model: Mailforge ($3.00), Premium Inboxes ($2.80-3.50), Infraforge ($4.00), Primeforge ($4.50)

Pros:

• Simple to understand
• Pay only for what you use
• Low entry point

Cons:

• Costs scale linearly (no volume discounts)
• Expensive at scale
• At 5,000 inboxes, you're paying $14,000-$22,500/month

MailDeck Per Inbox/Tenant Pricing

How it works: MailDeck offers multiple products: SMTP from $0.50/inbox, Google Workspace from $2.99/inbox, and Outlook tenants from $30/tenant. Volume discounts apply at higher tiers.

SMTP: $0.50/inbox (minimum 50 inboxes, $50/month)

Google Workspace: $3.90/inbox (1-249), $3.30/inbox (250-1,249), $2.99/inbox (1,250+) - minimum 10 inboxes ($39/month)

Outlook Normal: $30/tenant (100 inboxes per tenant) - minimum 2 tenants (200 inboxes, $60/month)

Outlook Premium: $40/tenant (100 inboxes per tenant) - minimum 2 tenants (200 inboxes, $80/month)

Pros:

• SMTP pricing significantly undercuts other providers at all scales
• Multiple infrastructure options (SMTP, Google Workspace, Outlook)
• Volume discounts at scale
• Predictable pricing

Cons:

• 48-hour setup time vs instant access at some per-inbox providers
• Infrastructure only - requires separate sequencer for campaigns

Tiered Pricing

How it works: Fixed monthly plans with included inbox counts. Additional inboxes cost extra.

Providers using this model: Mailscale (50/200 inbox tiers), Zapmail (tiered + per mailbox), Mailin (200/500/1,000 account tiers), Maildoso (70/300 inbox tiers)

Pros:

• Clear feature tiers
• Often includes additional features at higher tiers

Cons:

• Awkward scaling between tiers
• Need 51 inboxes? You're paying for 100
• Additional inbox rates often higher than base

Hidden Costs Most Providers Don't Mention

Infrastructure pricing tells only part of the story. Here are costs that affect your total cold email budget:

Domain Costs

Every cold email operation needs dedicated domains (never send from your primary domain).

• Cost: $10-15/domain/year
• At 1,000 inboxes (10 domains): $100-150/year
• At 5,000 inboxes (50 domains): $500-750/year

Some providers include domain purchase. Most don't.

Sequencer Costs

Infrastructure handles sending capacity. You still need a sequencer for campaigns.

Budget $50-200/month for sequencer costs in addition to infrastructure.

Warm-Up Period

New mailboxes need warming before high-volume sending.

• Duration: 2-4 weeks
• Impact: No revenue-generating sends during this period
• Some providers offer pre-warmed or aged mailboxes
• Native Microsoft 365 (MailDeck) inherits established reputation, reducing warm-up needs

DNS Management Time

Setting up SPF, DKIM, and DMARC for each domain takes time.

• Manual setup: 15-30 minutes per domain
• At 50 domains: 12-25 hours of work
• Automated setup (MailDeck, Maildoso, others): Often included

Deliverability Monitoring

Tracking inbox placement and sender reputation:

• Tools like Mailreach, Warmbox: $50-150/month
• Some providers include monitoring features

Secondary Domains: How Many You Need and What They Cost

The domain count for a campaign scales with inbox type, not just inbox count, and that's where most budgets underestimate secondary domain setup cost. MailDeck manages 1,200+ domains across its client base as of Q3 2026, and the split between Microsoft 365 and Google Workspace/SMTP domains looks very different at the same inbox total.

Microsoft 365 tenants pack 100 inboxes per domain. Google Workspace and Private SMTP pack 5 inboxes per domain. That 20x difference in inboxes-per-domain means the number of secondary domains a campaign needs, and the annual registration bill that comes with them, depends heavily on which infrastructure type is behind the inboxes.

Per-domain cost: budget $10-15/domain/year for registration, regardless of infrastructure type. The cost line item scales with domain count, not inbox count, which is why Outlook stacks stay cheap on domains even at high inbox counts (10 domains for 1,000 inboxes) while Google Workspace/SMTP stacks need 20x more domains for the same inbox total (200 domains for 1,000 inboxes).

Domain count isn't just about active sending capacity. At enterprise scale (100K+ emails/month), 10-20% of domains burn every month, with a typical domain lifespan of 45 days to 2 months under active load. Add a 20-25% reserve of warmed secondary domains on top of the active count so a burned domain can be swapped in within 1-3 days instead of the 7-10 days it takes to warm a fresh one from scratch. For a 1,000-inbox Outlook stack, that means budgeting for 12-13 domains instead of 10; for a 1,000-inbox Google Workspace/SMTP stack, budget for 240-250 domains instead of 200.

Example: A B2B SaaS client running 800 Outlook Premium inboxes needed 8 active domains plus a 2-domain reserve, for a total domain cost of $100-150/year, roughly 0.03% of their monthly infrastructure spend. A staffing agency client running 600 Private SMTP inboxes needed 120 active domains plus a 25-domain reserve, for a total domain cost of $1,740-2,175/year, closer to 8% of their monthly infrastructure spend at that inbox mix. The domain layer is a rounding error on Outlook stacks and a real budget line on SMTP/Google Workspace stacks.

How Much Should You Budget for Cold Email in 2026?

Based on our analysis, here are realistic total budgets for three scenarios:

Solo Founder / Small Team (50K emails/month)

Recommendation: If you need instant setup, start with Mailscale ($119 for 50 inboxes) or Maildoso ($158 for 70 inboxes). If you can wait 48 hours and want better long-term value, MailDeck's SMTP pricing (from $0.50/inbox for under 1,000 inboxes) provides room to grow.

Growing Agency (200K emails/month)

Recommendation: MailDeck SMTP pricing (~$400/month for 800 SMTP inboxes at $0.50/inbox) saves $2,400-3,200/month compared to other per-inbox providers. MailDeck also offers Google Workspace ($2.99-3.90/inbox) for teams needing that infrastructure.

Enterprise Operation (1M+ emails/month)

Recommendation: At enterprise scale, pricing model is critical. MailDeck SMTP at ~$1,800/month (4,000 inboxes at $0.50/inbox) vs. Primeforge at ~$18,000/month - a $16,200/month difference ($194,400/year). Factor in sequencer costs since MailDeck is infrastructure-only.

FAQ

How much does cold email infrastructure cost per month?

Cold email infrastructure costs between $0.40 and $4.50 per inbox per month in 2026. At 1,000 inboxes, total monthly costs range from $450 (MailDeck SMTP) to $4,500 (Primeforge). MailDeck offers SMTP, Google Workspace, and Outlook tenant products at different price points. Many providers require custom quotes above 500-1,000 inboxes.

What is the cheapest cold email infrastructure provider?

At 1,000 inbox scale, MailDeck SMTP is the cheapest with transparent pricing at $0.50/inbox ($500/month total). Mailin comes second at $1.49/inbox ($1,490/month). MailDeck also offers Google Workspace ($2.99-3.90/inbox) and Outlook tenants ($30-40/tenant).

Is MailDeck SMTP cheaper than per-inbox providers?

MailDeck SMTP pricing is cheaper at all scales. At 100 inboxes, MailDeck SMTP ($0.50/inbox) already beats most per-inbox providers. At 5,000+ inboxes, MailDeck SMTP ($0.50/inbox) costs 7-11x less than other per-inbox providers ($3.00-4.50/inbox).

How much do 1,000 cold email inboxes cost?

1,000 cold email inboxes cost between $500-$4,500/month depending on provider. MailDeck SMTP: $500/month. Mailin: $1,490/month. Mailforge: $3,000/month. Infraforge: $4,000/month. Primeforge: $4,500/month. Maildoso, Mailscale, and Zapmail require custom quotes at this scale.

What's the total cost of cold email including all tools?

Total cold email costs include infrastructure ($450-4,500/month for 1,000 inboxes), sequencer ($50-200/month), domains ($100-150/year for 10 domains), and optional monitoring tools ($50-150/month). Budget $600-5,000/month for a 1,000-inbox operation depending on provider choice.

Which providers offer native Microsoft 365 infrastructure?

MailDeck offers SMTP, Google Workspace, and Microsoft 365 Outlook tenants. Primeforge and Zapmail offer both Google Workspace and Microsoft 365 mailboxes. Most other providers use private SMTP infrastructure or Google Workspace only.

What's the minimum purchase for cold email infrastructure?

Minimum purchases vary: MailDeck minimums are Outlook 2 tenants (200 inboxes, $60/month), SMTP 50 inboxes ($50/month), Google Workspace 10 inboxes ($39/month). Mailscale starts at $119/month for 50 inboxes. Maildoso offers a 70-inbox plan at ~$158/month. Per-inbox providers like Mailforge, Infraforge, and Primeforge typically allow purchasing individual mailboxes with instant setup.

How many secondary domains does a cold email campaign need?

Domain count depends on infrastructure type, not just inbox count. Microsoft 365 Outlook tenants pack 100 inboxes per domain, so 1,000 Outlook inboxes need only 10 domains. Google Workspace and Private SMTP pack 5 inboxes per domain, so 1,000 inboxes on those infrastructure types need 200 domains. Add a 20-25% reserve of warmed domains on top of the active count to cover monthly burn at enterprise scale.

Methodology Notes

Data collected: March 16, 2026

Providers analyzed: 11

Prices verified: From official pricing pages

Updates: This analysis will be updated quarterly as providers change pricing

For current pricing, visit each provider's website directly. Links to provider comparisons and best infrastructure guide available on our blog.