How is Combo (SMTP + Google Workspace) different from pure SMTP on Maildoso?

Combo mailboxes route through Google Workspace, so delivery actually happens over Google's MX infrastructure. Pure SMTP routes through Maildoso's own sending fabric instead. The Combo premium ($2-$3 versus $1.90-$2.50) reflects a genuine Google Workspace license cost underneath it. Combo typically delivers 5-15 percent better to Google-heavy recipient lists, though that gap narrows on Microsoft-heavy ones.

Does Maildoso's 400K-mailbox track record actually matter at smaller scale?

Less for small fleets, considerably more once you're past 200 mailboxes. The operational failure modes Maildoso has already engineered around — DNS propagation at scale, IP pool stability, capacity continuity — only really surface past a certain threshold. A 50-mailbox fleet on Maildoso feels much like a 50-mailbox fleet anywhere else; a 1,000-mailbox fleet is where the track record difference becomes directly noticeable.

What does Maildoso's shared IP pool mean for buyer-level deliverability?

Your reputation is influenced by whatever else is happening on your shared IP pool. Maildoso's scale and 4.7 G2 rating suggest the pool composition is well-managed at the provider level overall, but there's no way to check your specific pool before provisioning. For high-volume senders with strict deliverability requirements, that uncertainty is the argument for a dedicated-IP provider like Infraforge, regardless of the rate difference.

How much does the API and MCP support actually save at scale?

At 500-mailbox provisioning, the gap between API-driven setup and manual panel-clicking runs roughly 20-40 operator hours. At $80-$150 per hour, that's $1,600 to $6,000 in savings just on initial provisioning, with some of that recurring every month afterward. It's the line item that never appears on the pricing page but ends up shaping real-world economics at scale.

Do I need to add domain costs separately when modeling Maildoso bills?

Yes. Mailbox prices ($1.90-$3) cover only the mailboxes themselves — domains are $2 each and aren't bundled in. A typical fleet runs about one domain per 5-10 mailboxes for reputation diversification, so a 100-mailbox fleet might add $20-$40 in domain fees and a 500-mailbox fleet $100-$200. Registering domains through Maildoso is convenient but not required; bringing your own is supported too.

Maildoso Pricing: The Real Numbers

A full breakdown of every Maildoso plan, mailbox type, and domain cost — what you actually pay at scale, and how it stacks up against InboxKit.

By Ritesh Chauhan

6 min readUpdated Mar 2026

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Bottom line

Maildoso is the volume specialist in this category. SMTP mailboxes start at $1.90 each, the Combo tier (SMTP plus Google Workspace) runs $2-$3, and domains start at $2. That published rate is the lowest in the category, and the operational history behind it — 400,000-plus mailboxes under management, 10 million-plus daily sends — backs it up with a scale capacity newer providers simply haven't demonstrated yet.

The deliberate trade-off is no bundled deliverability tooling: no warmup, no verifier, no placement testing, no blacklist monitor. What you're buying is raw SMTP, priced to make 100-500 mailbox fleets economically viable, on the assumption that warmup and monitoring live in whatever sending platform sits on top.

How Sendbox compares

Sendbox plans start at $99/mo with dedicated IPs and the full deliverability suite included on every tier — no add-ons required.

View Sendbox Pricing Sendbox vs Maildoso Browse Features

Maildoso Plans

Plan	Price	What you get	Watch out for
SMTP Mailboxes billed per mailbox	$1.90-$2.50/mailbox/mo	SMTP mailboxes on Maildoso's own sending fabric DNS configures automatically One-click integrations with Instantly, Smartlead, and Saleshandy API and MCP support included	Runs on shared IP infrastructure No native warmup No placement testing No email verifier
Combo (SMTP + GW) billed per mailbox	$2-$3/mailbox/mo	Blends SMTP with Google Workspace mailboxes DNS configures automatically One-click integrations included API and MCP support included	Still runs on shared IPs Costs more than the SMTP-only tier No native warmup or deliverability tooling
Domains billed per domain	From $2/domain	Domain purchase and management handled for you DNS records set up automatically	Price varies depending on the TLD and availability

What's Not Included

The real hidden cost is the deliverability-tooling assumption

Maildoso's pricing math works on the assumption that your sending platform already covers warmup, verification, placement testing, and blacklist monitoring. For teams running Smartlead, Instantly, or a similar all-in platform, that assumption holds and the raw $1.90 rate really is the floor. For teams running a barebones sequencer or building something custom on top of SMTP, sourcing those missing tools standalone runs $75-$200/mo regardless of fleet size, which eats into the savings versus an all-in provider like InboxKit at $2.50.

$75-$200/mo if not covered by sending platform

The SMTP-vs-Combo rate gap is a real cost lever

The published SMTP range runs $1.90-$2.50 and the Combo range runs $2-$3. That gap isn't arbitrary — Combo mailboxes route through Google Workspace, so there's a real underlying license cost behind it. Wanting Google Workspace mailboxes means paying roughly 30-60 percent more than pure SMTP. The choice between the two usually comes down to deliverability rather than cost (Google routing often places better), but the cost gap is real and compounds fast across hundreds of mailboxes.

$0.10-$0.60/mailbox premium for Combo over pure SMTP

Domains are billed separately, not bundled into mailboxes

Mailbox prices don't include domains. A typical cold email fleet runs roughly 1 domain per 5-10 mailboxes for reputation diversification, and that adds up at scale — a 200-mailbox fleet spread across 25 domains adds $50 in domain fees on top of the mailbox bill. Maildoso prices domains transparently at $2 each, but they're not folded into the per-mailbox rate, so anyone modeling cost should add that line separately every time.

$2 per domain, $40-$100/mo at typical fleet sizes

You can't see which IP pool you're actually landing on

Maildoso's SMTP fleet shares IP pools across its entire customer base. The provider's deliverability claims (and the 4.7 G2 rating) hold up at the provider level overall, but individual outcomes depend on which specific pool a given buyer lands on. There's no published way to check or audit pool composition before provisioning — a real operational consideration at high volume, but one that rarely comes up in a straight pricing comparison.

Indirect (potential deliverability variance)

What Maildoso actually costs at typical fleet sizes

Usage scenario	Monthly cost	Notes
50 SMTP mailboxes, 10 domains	$115-$145/mo	50 mailboxes at $1.90-$2.50 each plus 10 domains at $2 each. At this volume, pure SMTP is the cheapest configuration in the category, assuming your sending platform covers warmup and monitoring.
100 SMTP mailboxes, 20 domains	$230-$290/mo	100 mailboxes at $1.90-$2.50 each plus 20 domains at $2 each. Whether Maildoso's cost edge over InboxKit ($250) holds at this size depends entirely on whether your sending platform covers the deliverability gap.
200 Combo mailboxes, 30 domains	$460-$660/mo	200 mailboxes at $2-$3 each plus 30 domains at $2 each. At this volume, the Combo tier (GWS-backed) is the sweet spot for teams wanting Google routing without paying retail GWS rates of $7/seat.
500 SMTP mailboxes, 75 domains	$1,100-$1,400/mo	500 mailboxes at $1.90-$2.50 each plus 75 domains at $2 each. This is where Maildoso's scale story really earns its keep: provisioning and managing 500-plus mailboxes is operationally heavy, and its track record (400K+ mailboxes managed) is what provides the throughput to handle it.
1,000+ mailbox fleet	$1,900-$2,500+/mo	Maildoso's claimed 10M+ daily send capacity is the number that matters at this scale. The per-mailbox rate amortizes fine, but operational continuity is the real question at this volume, and Maildoso has the longest track record in the category to answer it.

The 400K-mailbox track record is the pricing premium that does not show on the page

Maildoso's public pricing is competitive on a pure per-mailbox basis, but the more telling story here is operational: 400,000-plus mailboxes under management, 10 million-plus daily sends processed. Most competitors in this category are newer (Mailforge, Infraforge, InboxKit, and Zapmail all launched post-2022) and haven't had the chance to prove continuity at this scale. Maildoso has been running provisioning, DNS automation, and fleet management long enough that its failure modes have surfaced and gotten engineered around.

That matters because the failure modes of email infrastructure don't reveal themselves until volume forces the issue: DNS propagation problems at high provisioning rates, IP pool degradation under multi-tenant load, MX record drift on dormant domains, capacity bottlenecks during industry-wide sending spikes. Newer providers can match Maildoso's sticker price easily enough, but they can't match the operational data on how a platform behaves under sustained load in the 100K-to-1M-mailbox range. For a buyer making a multi-year infrastructure commitment, that track record is essentially the price of avoiding the unknown.

Maildoso's 4.7 G2 rating (159 verified reviews) is unusually strong for this category, and it reflects the operational reality more than it does the headline price.

Key takeaways

400,000+ mailboxes currently under management
10M+ emails processed daily at platform scale
4.7-star G2 rating from 159 verified reviews
An operational track record newer providers simply haven't had time to build

The SMTP-vs-Combo choice is the most-overlooked pricing lever

Maildoso publishes two tiers: pure SMTP ($1.90-$2.50) and Combo ($2-$3, blending SMTP with Google Workspace). The naming undersells what's actually different between them. Pure SMTP runs through Maildoso's own sending fabric and lands based on Maildoso's IP reputation.

Combo mailboxes route through Google Workspace instead, meaning delivery actually happens over Google's MX servers and benefits from Gmail-to-Gmail inbox-preference behavior. That deliverability gap is real, but how much it matters depends on your workflow. Sending to a B2B list dominated by Google Workspace recipients, Combo typically lands 5-15 percent better.

Sending to a mixed Microsoft 365 or corporate-IT-server list, that gap narrows or even flips. The 30-60 percent Combo premium (usually $0.50-$0.80 more per mailbox) only pays off when your recipient mix genuinely favors Google routing. The optimization most teams skip is running a 30-day deliverability test on a representative sample — say, 5,000 sends each through SMTP and Combo — and picking the tier based on that data instead of assumption.

Plenty default to pure SMTP for the savings and leave placement gains on the table; others default to Combo for the reputation boost and overpay for routing they didn't actually need.

Key takeaways

Pure SMTP: Maildoso's own fabric, lower cost
Combo: routes through GWS, 5-15 percent better placement on GWS-heavy lists
Combo carries a 30-60 percent premium over SMTP
Pick the tier based on a recipient-mix test rather than a guess

The MCP and API support is a pricing-relevant feature at scale

Maildoso ships both API access and MCP (Model Context Protocol) support, which most competitors don't offer. At 50-mailbox scale, that's a nice-to-have. At 500-mailbox scale, it stops being optional — manual provisioning becomes genuinely infeasible once every new domain, naming convention, and DNS verification adds up to hours of clicking through panels.

That API and MCP integration is really what makes Maildoso's scale claim (400K mailboxes managed) credible for its largest customers. The cost implication follows from that: a 500-mailbox fleet on Maildoso can be scripted and provisioned in a few hours. The same fleet on a provider without API access means days of manual work plus ongoing overhead.

At $80-$150 per hour of operator time, that gap quickly outweighs any per-mailbox savings you'd get from an API-less alternative. For agencies and large in-house teams modeling total cost, this is the line item that never shows up on the pricing page but ends up determining the real-world economics at the high end of the scale range.

Key takeaways

API and MCP support enables automated provisioning
Becomes essential past 500 mailboxes, where manual work stops being feasible
Time saved on operators can outweigh any per-mailbox cost gap
A cost factor that never appears on the public pricing page

When Maildoso is structurally the right pricing choice

Maildoso fits cleanly when three things line up. First, your sending platform already covers warmup, validation, placement testing, and blacklist monitoring, so the savings on raw mailboxes is genuine rather than a false economy from skipping tools you actually need. Second, your volume is high enough that the per-mailbox difference actually matters — under 30-50 mailboxes, the absolute dollars are too small to justify treating infrastructure as a separate decision.

Third, you value operational continuity at scale over whatever a newer provider offers at comparable rates. It fits less cleanly when those conditions flip. Teams running barebones sequencers without deliverability tooling end up paying the gap to InboxKit anyway to get the bundle.

Teams running small fleets pay roughly the same regardless of provider. Teams comfortable betting on a newer provider can match Maildoso's rate on Mailforge ($2-$3) or beat it on bundled value with InboxKit ($2.50). The real question is which trade-off matches how you actually operate.

Key takeaways

Best fit: your sending platform already covers deliverability, and volume is high
Poor fit: small fleets, or no separate deliverability tooling elsewhere
The trade-off is cheapest rate versus a bundled deliverability stack
The operational track record favors teams making a large-scale commitment

Keep reading

Sources

maildosoG2 Website

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When your sending platform doesn't already cover warmup, verification, placement testing, and blacklist monitoring. Sourcing those tools standalone runs $75-$200/mo regardless of fleet size, which eats into the per-mailbox savings versus a bundled provider. At 100 mailboxes, raw Maildoso ($190) plus standalone tooling ($75-$150) lands at $265-$340, against InboxKit's $250 all-in.

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