Mailscale vs Maildoso: Which Email Infrastructure Is The Right Choice?

I have set up cold email infrastructure on all three of these providers over the last 18 months. This is not a sponsored post. I run outbound for B2B SaaS clients, and the mailbox provider decides whether a quarter produces pipeline or burned domains.

Mailscale and Maildoso both lead with price and shared SMTP. Primeforge sells real Google Workspace and Microsoft 365 mailboxes that send from US IPs and look, to a receiving filter, like the mailboxes your buyers already use.

The gap rarely shows on day one. It shows around week seven, when a shared IP picks up a bad neighbor. Every price below came from the live vendor pages in June 2026.

Cold Email Infrastructure Comparison at a Glance: Mailscale vs Maildoso

Mailscale Overview: SMTP-Only Cold Email Infrastructure

Mailscale is a cold email mailbox provider founded in late 2023 by Yassin Baum. The product is SMTP-only. Mailscale runs its own SMTP servers and IP pools and hands you mailboxes that plug into Instantly, Smartlead, Apollo, Lemlist, or Reply.io. There are no real Google Workspace mailboxes and no Microsoft 365 mailboxes.

The pitch is speed and cost. Mailscale claims 50 inboxes in under 60 seconds, cites 3,000+ customers, and tells visitors that Google and Outlook were not built to scale cold outreach.

Core features

• SMTP mailboxes on shared infrastructure with automated SPF, DKIM, and DMARC
• Domains bought inside Mailscale at $10 to $15 per .com per year, or bring your own for $2 per domain
• A 95 to 100% deliverability guarantee, with free domain replacement if placement stays under 80% after a 30-day recovery
• One-click CSV export of credentials into any IMAP/SMTP sending tool
• Recommended volume of 30 to 50 cold emails per inbox per day
• A cold email course bundled with the Business plan

Pricing

Mailscale now publishes pricing on its homepage, with a self-serve 7-day free trial on each tier. If you read older reviews saying the numbers were demo-gated, that has changed.

Solopreneur is $79/mo for 15 inboxes ($5.27 each). Business is $119/mo for 50 inboxes ($2.38 each). Enterprise is $249/mo for 200 inboxes ($1.25 each), with extra inboxes at $1.50/mo. An Unlimited plan starts at $1,000+/mo and adds dedicated IPs plus a deliverability specialist. The refund policy is strict: no refunds once mailboxes are provisioned.

Who Mailscale fits

Solo founders and small teams running one outbound motion who want the fastest SMTP setup and accept shared IPs as the trade-off. I went deeper on the product in my full Mailscale review.

What reviewers say

Mailscale holds a 4.8 on G2 across 58 reviews, most of them praising setup speed. Trustpilot sits lower at 4.1 across 88 reviews as of late May 2026, and the 1-star cluster is about shared-IP placement. One verified reviewer documented deliverability under 50% by week two, twice, even after an IP move.

Honest observations

• SMTP-only means no ESP matching: you cannot send Gmail-to-Gmail or Outlook-to-Outlook
• The deliverability guarantee only covers domains bought inside Mailscale; bring your own and it is voided
• Mailscale's own FAQ says deliverability "isn't a function of infrastructure or mailboxes anymore" - worth weighing before buying infrastructure from anyone
• When a shared IP burns, the documented fix is moving you to a new IP, which costs days of active sending

Maildoso Overview: Shared SMTP With a Google Workspace Add-On

Maildoso is a cold email infrastructure provider at maildoso.ai, operated by BacklinkSwappers, Inc. out of San Francisco. The base product is shared SMTP mailboxes with IP rotation. Real Google Workspace mailboxes are available through Combo bundles, and there is no Microsoft 365 option at any tier.

Maildoso reports 10M+ emails sent per day, 400,000+ mailboxes managed, 6,000+ companies served, and a 4.7 G2 rating across 179 reviews. The pitch is the lowest published per-mailbox price on the market, from $1.80, plus self-healing tech that pauses burned mailboxes for 14 days.

Core features

• SMTP mailboxes on shared IPs with automatic rotation across many addresses
• Optional real Google Workspace mailboxes from $2.50 in Combo bundles, aimed at Gmail and Outlook recipients
• Self-healing mailboxes: burned accounts pause for 14 days, then return to rotation
• Inbox placement tests every three days with per-mailbox health scores
• A master inbox for replies, plus primary-domain masking behind a captcha
• One-click sync with Instantly, Smartlead, and EmailBizon, plus a developer API and MCP server
• Recommended volume of 15 cold emails per SMTP mailbox per day

Pricing

Everything is published. Monthly SMTP runs $75 for 30 mailboxes ($2.50 each), $158 for 70 ($2.25), and $570 for 300 ($1.90). Quarterly SMTP runs $299 for 32 mailboxes ($3.10 each), $499 for 68 ($2.40), and $2,199 for 400 ($1.80), with domains included free.

Combo plans bundle SMTP and Google Workspace at $90 for 15+15, $175 for 35+35, and $675 for 150+150. Monthly plans bill domains separately. There is a 30-day money-back guarantee and a stated no-discount policy.

Who Maildoso fits

Agencies and teams chasing the lowest published SMTP price who accept shared IPs and, for the cheapest rates, a quarterly commitment paid up front. I covered the day-to-day in my hands-on Maildoso review after running 30+ accounts.

Honest observations

Maildoso's weak points are documented, but they live on G2 and Reddit rather than on screenshot-friendly review sites, so I will summarize them here. Shared SMTP means your reputation is partly set by IP neighbors. A 100-mailbox Reddit test, which Maildoso itself links from its site footer, reported a batch of mailboxes hitting spam around weeks seven and eight before rotation recovered them, at the cost of active sending days.

G2 reviewers flag support response times and deliverability swings at scale. Several users report replacement domains arriving on .xyz or .click instead of .com, which reads as spam to B2B filters. Real Google Workspace is an add-on, not the base product. And if your buyers live in Outlook, there is no Microsoft 365 here at all - that is a job for a dedicated Microsoft mailbox provider.

Primeforge Overview: Real Google Workspace and MS365 Mailboxes

Primeforge is the Google Workspace and Microsoft 365 layer of the Forge Stack. Where Mailscale and Maildoso build on shared SMTP, Primeforge provisions real Google and real Microsoft business mailboxes configured for cold outreach. Every mailbox ships with a US-based IP, a profile picture, and automated SPF, DKIM, and DMARC.

No EDU loopholes and no reseller panels, which matters more than ever after Google's crackdown on EDU and legacy reseller mailboxes. These are accounts Google and Microsoft issued, on infrastructure they run.

Primeforge is one product inside the Forge Stack, next to Mailforge (shared IPs at $2 to $3/mailbox), Infraforge (private dedicated IPs at $3 to $4/mailbox), Warmforge (warm-up and monitoring), Leadsforge, and Salesforge. The Salesforge team's own guidance is to mix two or more ESPs, a pattern I broke down in the hybrid email infrastructure guide, so you always send from a provider matching your prospect's inbox.

Core features

• Real Google Workspace and Microsoft 365 mailboxes, not EDU tricks or reseller hacks
• US-based IP addresses on every mailbox
• Automated DNS for SPF, DKIM, DMARC, and custom tracking domains
• 30-minute setup from signup to first send
• Pre-warmed mailboxes for teams that need to send on day one
• Profile pictures and GIFs configured at scale
• Bulk DNS updates across hundreds of domains
• Multiple workspaces, one per client, for agencies
• Primeforge API for programmatic mailbox management
• SOC 2 compliant infrastructure with native hooks into Salesforge and Warmforge

Pricing

Slots cost $4.50/mailbox monthly or $3.50/mailbox on annual billing, which works out to 2 months free. Domains are $14/year for a .com, registered to you. The calculator on the pricing page shows exact costs, and you can verify the live price for your own setup.

One worked example from the calculator: 25 mailboxes across 9 domains runs $94/month billed annually, or $113/month billed monthly, plus $126 in one-time domain registrations. Slots are reusable: delete a mailbox and create a new one in the same slot at no extra charge.

Who Primeforge fits

B2B teams and agencies where deliverability is the budget item: 30 to 200 mailboxes across 10 to 70 domains, ESP-matched sending into Google and Microsoft inboxes, and isolated infrastructure per client.

Real customer proof

J-Reach, a LinkedIn outreach training company, runs 23 domains and 69 mailboxes on Primeforge. The published J-Reach case study documents six months of continuous use with zero bounce issues and zero mailbox failures. In CEO Yap Junte's words: "I've never had any issues with bouncing or mailboxes dying out of nowhere."

Reviewers tell the same story. Here is one agency operator on Trustpilot:

Honest limitations

• No free trial: Primeforge is infrastructure, so you buy slots and domains
• Each Forge product is a separate subscription; there is no single bill across the stack
• Per-mailbox cost is higher than SMTP at scale; you pay for real Google and Microsoft accounts
• The recommended hybrid setup means budgeting for a second infrastructure product if you want maximum resilience

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Head-to-Head Feature Comparison: Mailscale vs Maildoso

Here is where the three actually separate, axis by axis.

Mailbox type and ESP authenticity

This is the biggest gap. Mailscale sells SMTP only. Maildoso sells SMTP as the base, with real Google Workspace as a paid bundle and no Microsoft 365 at all. Primeforge sells real Google Workspace and real Microsoft 365 as the default product.

When your prospect is on Gmail, a real Google Workspace sender is a known peer to the receiving filter. Same for Outlook and a real MS365 sender. I compared the two models in Google Workspace vs private SMTP, and the short version is that ESP matching lifts primary-inbox placement in ways an unfamiliar SMTP server cannot. Mailscale cannot do this at any price. Maildoso can do half of it, Google only, on the Combo tier.

Deliverability and warm-up

Mailscale publishes a 95 to 100% guarantee, restricted to domains bought inside Mailscale, with a 30-day recovery window. Its stated position is that landing in the inbox comes down to spintax and copy tactics rather than infrastructure. The Trustpilot record shows the practice: the January 2026 review above documents placement under 50% by week two, on two different IPs.

Maildoso is more candid about the physics. Placement tests run every three days, and the self-healing system exists because shared SMTP burns under load: paused 14 days, then back into rotation.

Primeforge mailboxes carry reputation individually, because each one is a real Google or Microsoft account on a US IP. Warm-up runs through Warmforge, free with any Salesforge subscription, or you can buy pre-warmed slots. After two weeks of warm-up, J-Reach ran six months without a single failure across 69 mailboxes. Before any launch, I also run a free inbox placement test to confirm the setup.

Daily volume per mailbox

Vendor volume guidance changes the real price. Maildoso's pricing page recommends 15 cold emails per SMTP mailbox per day. Mailscale recommends 30 to 50, and Forge guidance for Primeforge mailboxes is also 30 to 50.

So to send 1,000 cold emails a day, you need roughly 67 Maildoso SMTP mailboxes, but only 25 to 34 mailboxes on Mailscale or Primeforge. Per-mailbox price and per-send price are different numbers. I run the math in the pricing section below.

Pricing model and exit terms

All three publish pricing. Mailscale offers a 7-day free trial, then a no-refund policy once mailboxes are provisioned. Maildoso offers no trial but a 30-day money-back guarantee, plus a stated no-discount policy. Primeforge has neither a trial nor a refund window: it is a slot subscription with a live calculator, monthly or annual.

The structural difference is tiering. Mailscale and Maildoso sell fixed buckets, and Maildoso's published monthly path jumps from 70 mailboxes straight to 300. Mailscale softens this with $1.50 add-on inboxes on Enterprise. Primeforge is per-slot, so 80 mailboxes costs exactly 80 slots.

Scale, ownership, and infrastructure burn

On shared SMTP, your reputation is partly set by IP neighbors, and replacement quality matters. Maildoso users on G2 and Reddit report .xyz and .click replacement domains. Mailscale replaces domains only if you bought them inside Mailscale.

Primeforge domains are registered to you at $14/year, and reputation travels with each Google or Microsoft account rather than a pool. Teams that want raw IP control on top of that layer in Infraforge dedicated IPs alongside Primeforge - the two-ESP pattern from the hybrid guide above.

Stack, API, and compliance

Mailscale exports a CSV of credentials and has no public API. Maildoso ships a developer API and an MCP server, plus one-click sync into Instantly, Smartlead, and EmailBizon, which is useful if you script your infrastructure.

Primeforge ships its own API and connects natively to the rest of the Forge Stack: Leadsforge finds contacts, Primeforge hosts mailboxes, Warmforge keeps them healthy, and Salesforge sends the sequences, with no Zapier glue between them.

On compliance, Primeforge is SOC 2 compliant, with a public Trust Center. Neither Mailscale nor Maildoso advertises SOC 2 on its site. If you sell into regulated buyers, this surfaces at security review, not at signup.

Cold Email Mailbox Pricing Compared

Headline per-mailbox prices favor the SMTP vendors. Per-send prices do not. Take a 1,000-cold-emails-per-day target.

At Maildoso's recommended 15 sends per SMTP mailbox, you need about 67 mailboxes: the 70-box plan at $158/mo. At 30 sends per mailbox, Primeforge needs 34 slots: $119/mo on annual billing, plus roughly $13/mo in domain costs spread across the year. Mailscale's Business plan covers the same volume at $119/mo for 50 inboxes under its 30-to-50 guidance.

So at identical daily volume, real Google Workspace from Primeforge costs about the same as Mailscale's shared SMTP and less than Maildoso's, while sending from the ESP your prospects actually use. The premium only reappears if you compare mailbox-to-mailbox instead of send-to-send.

At raw scale the SMTP discount is real: 200 Mailscale Enterprise inboxes cost $249/mo against roughly $700/mo for 200 Primeforge slots on annual billing. That $451/mo gap is the price of real Google and Microsoft accounts instead of shared SMTP. Whether it is worth paying depends on what a burned campaign costs you. J-Reach decided it was.

Who Should Use Which Cold Email Infrastructure

You might consider Mailscale if

• You run fewer than 50 mailboxes, want setup in minutes, and plan to use the 7-day trial to test placement yourself
• Your sending tool already takes IMAP/SMTP credentials and ESP matching is not part of your motion
• You accept the no-refund policy and shared IPs as the cost of $1.25-to-$5.27 inboxes

You might consider Maildoso if

• You want the lowest published SMTP price and can commit quarterly for the $1.80 rate with free domains
• Your targets skew Gmail and you plan to add the Google Workspace Combo bundle
• A 30-day money-back window matters more to you than a trial

Choose Primeforge if

• You sell B2B into companies on Google Workspace or Microsoft 365 and want ESP-matched sending
• Deliverability is the budget item, not the line you cut to close a $56/mo gap at 50 mailboxes
• You run agency outbound and need isolated workspaces, bulk DNS, and domains you own
• Your buyers run security reviews and SOC 2 will come up
• You want one connected stack for mailboxes, warm-up, leads, and sequences instead of duct-taped point tools

One honest anti-fit: if you need 1 to 5 mailboxes for normal daily email, buy Google Workspace from Google. Primeforge is built for cold outreach at scale, not everyday mailboxes.

If you are weighing other vendors, I ran the same lens over Zapmail vs Mailscale, and the full comparison library covers the wider market.

Final Verdict: Which Cold Email Infrastructure to Choose

Mailscale and Maildoso are both shared-SMTP products with real price advantages and the same structural weakness: your reputation rides on a pool you do not control. Mailscale pairs the fastest setup with a no-refund policy and a Trustpilot record of week-two burn. Maildoso publishes everything, refunds for 30 days, and recommends just 15 sends per mailbox per day, which quietly erases its price lead at equal volume.

For B2B cold email, Primeforge is the stronger choice. Real Google Workspace and Microsoft 365 mailboxes on US IPs, 30-minute setup, SOC 2 compliance, and per-send economics that match Mailscale at 1,000 emails a day.

The falsifiable benchmark: J-Reach has run 23 domains and 69 Primeforge mailboxes for six months with zero failures and zero bounce issues, in a public, named, dated case study. Neither competitor has published an equivalent claim at comparable scale.

And solid infrastructure is what the rest of the stack builds on. This is real multi-channel campaign data from the Forge Stack once the mailbox layer holds:

Frequently Asked Questions

Is Primeforge better than Mailscale and Maildoso?

For B2B cold email into Google and Microsoft inboxes, yes, and that is the recommendation this page builds to. Primeforge ships real Google Workspace and Microsoft 365 mailboxes on US IPs, and the J-Reach case study documents six months of zero failures across 69 mailboxes. On raw per-mailbox price, Mailscale Enterprise costs $1.25 and Maildoso's quarterly tier costs $1.80. At equal daily volume that gap mostly disappears, because Maildoso recommends only 15 sends per SMTP mailbox per day.

What is the difference between SMTP mailboxes and real Google Workspace mailboxes?

SMTP mailboxes run on the provider's own servers and shared IP pools, so receiving filters see an unfamiliar sender. A real Google Workspace mailbox is an actual Google business account: when your prospect uses Gmail, you are a known peer on the same ESP, and that match lifts primary-inbox placement. Mailscale sells SMTP only. Maildoso sells SMTP as the base with Google Workspace as a paid bundle. Primeforge sells real Google Workspace and Microsoft 365 by default.

Which is cheaper: Primeforge, Mailscale, or Maildoso?

It depends on how you count. Per mailbox, Mailscale Enterprise is $1.25 and Maildoso's 400-box quarterly plan is $1.80, against Primeforge's $3.50 on annual billing. Per send, the order changes: 1,000 cold emails a day needs 34 Primeforge mailboxes at $119/mo annual, or about 67 Maildoso SMTP mailboxes at its 15-per-day guidance, which means the $158/mo plan. Mailscale's Business plan also lands at $119/mo for that volume.

Does Mailscale offer Google Workspace or Microsoft 365 mailboxes?

No. Mailscale is SMTP-only and positions itself against Google and Microsoft directly, arguing they were not built for cold outreach. If you want ESP-matched sending, Maildoso offers real Google Workspace as a Combo add-on from $2.50 per mailbox, and Primeforge ships both real Google Workspace and real Microsoft 365 as the default product, ready in 30 minutes.

Does Maildoso offer Microsoft 365 mailboxes?

No. Maildoso sells shared SMTP mailboxes and optional real Google Workspace accounts, but no Microsoft 365 at any tier. If a meaningful share of your prospects sit in Outlook, that is a structural gap, because ESP matching into Microsoft inboxes requires a real MS365 sender. Primeforge provisions Microsoft 365 mailboxes alongside Google Workspace at the same $4.50 monthly ($3.50 annual) slot price.

Can I switch from Mailscale or Maildoso to Primeforge easily?

Yes, with one caveat. Domains move: Mailscale states domains you bought inside stay yours if you cancel, and Maildoso transfers registered domains back at no charge when a subscription ends. Primeforge accepts your own domains and automates the DNS. Mailbox history does not migrate anywhere, so plan a two-week Warmforge warm-up on the new mailboxes, or buy pre-warmed Primeforge slots to skip the wait.

Which has better email deliverability?

Deliverability is a function of mailbox type, IP reputation, warm-up, and sending behavior. On shared SMTP, your reputation is partly set by IP neighbors: Maildoso runs placement tests every three days and pauses burned mailboxes for 14 days, and Mailscale's Trustpilot record includes documented week-two burn. Primeforge reputation travels with each real Google or Microsoft account. The strongest public data point is J-Reach: 69 mailboxes, six months, zero failures.

Does Primeforge offer a free trial?

No. Primeforge is infrastructure, so you buy mailbox slots and domains rather than starting a trial. Annual billing gives 2 months free, $3.50 instead of $4.50 per mailbox, and slots are reusable: delete a mailbox and create a new one in the same slot at no extra charge. The pricing calculator shows the exact monthly and annual cost for any setup before you pay.