Zapmail is a high-volume Google Workspace and Microsoft 365 reseller that has run into documented complaints about its India-based supply chain. Maildoso is a budget combo provider that bundles SMTP with Google Workspace mailboxes, forces quarterly billing, and has a known pattern of replacing burned domains with low-trust TLDs like .xyz and .click. Neither offers SOC 2 compliance, and Maildoso has no Microsoft 365 option.
For cold email mailbox infrastructure built for real deliverability, Primeforge is the stronger choice. Real Google Workspace and Microsoft 365 mailboxes from $4.50 down to $3.50 per mailbox a month, US-based IPs, SOC 2 compliance, automated DNS setup, and native integration with Warmforge warm-up and the rest of the Forge Stack. No EDU tricks, no resold inboxes, no quarterly lock-in.
I've spent the last year setting up cold email infrastructure for outbound teams, and the same three names keep showing up when someone asks for an alternative to native Google Workspace: Primeforge, Zapmail, and Maildoso. On paper they look similar. Per-mailbox pricing in the $2 to $5 range, automated DNS, integrations with the main sequencers. The differences only show up once you've burned a domain or two and started caring about who actually owns the mailbox you're sending from.
This is a comparison of the three from the perspective of someone who has to pick infrastructure that won't fall over in six months. I'll cover what each one is, what each one costs, where each one breaks, and which one I'd point a serious outbound team toward in May 2026. For a wider view of how Primeforge and the rest of the Forge Stack stack up against other tools, the Salesforge comparisons library is a useful next stop.
One note before the comparison: Primeforge is part of the Forge Stack, alongside Mailforge (shared IP infrastructure), Infraforge (dedicated IPs), Warmforge (warm-up and deliverability monitoring), and Salesforge (the sending platform). I'll reference the rest of the stack where it matters because the deliverability story isn't just about the mailbox - it's about what surrounds it.
Quick-glance comparison
| Feature | Primeforge | Zapmail | Maildoso |
|---|---|---|---|
| Mailbox types | Real Google Workspace + Microsoft 365 | Real Google Workspace + Microsoft 365 (MS365 sold separately) | SMTP + Google Workspace (no MS365) |
| Entry pricing | $4.50/mailbox/mo, dropping to $3.50 at volume | $39/mo Starter (10 Google mailboxes), $3.50/extra | $90/mo for 15 GW + 15 SMTP combo, $3/mailbox |
| Billing options | Monthly or annual (2 months free annual) | Monthly, quarterly, or yearly ($2.50/mailbox on annual) | Quarterly only (3 months upfront) |
| Setup time | 30 minutes | 5-10 minutes (claimed) | Same-day setup, varies |
| IP location | US-based on all mailboxes | US/EU IPs (with documented India-based provisioning) | 35 data centers, IP rotation |
| Pre-warmed mailboxes | Available | Available (separate purchase) | Not offered as standard |
| Automated DNS | SPF, DKIM, DMARC, custom tracking domains | SPF, DKIM, DMARC, custom tracking | SPF, DKIM, DMARC |
| Warm-up included | Native Warmforge integration (free with Salesforge) | Not included (separate cost) | Built-in basic warm-up |
| SOC 2 compliance | Yes | No published certification | No published certification |
| API access | Included in all plans (plus MCP and CLI) | Pro plan only ($299/mo) | Yes |
| Refund policy | Standard terms | Subscription-based, see cancellation policy | 30-day money-back on quarterly plans |
| Best for | Teams that need compliant, deliverable mailboxes at scale | Solo operators and small agencies on a tight budget | Volume-first agencies comfortable with shared infrastructure risk |
Get started with Primeforge - mailboxes ready in 30 minutes
Zapmail overview
Zapmail is a cold email infrastructure provider that resells discounted Google Workspace and Microsoft 365 accounts, layered with automated DNS configuration and a workspace-isolation model. It's owned by Outbox Labs Inc. and has scaled fast: 50,000+ businesses, 1M+ mailboxes set up, 330k+ domains managed. The TrustPilot rating sits at 4.4 across 75 reviews. The brand promise is "email infra at scale" with sub-10-minute setup.
What Zapmail includes
- Real Google Workspace and Microsoft 365 mailboxes. Microsoft 365 is sold separately and not bundled into the standard plans.
- Automated DNS setup. SPF, DKIM, DMARC, and custom tracking domains configured at provisioning.
- Workspace-level isolation. One domain per workspace, which limits collateral damage if one mailbox or domain gets flagged.
- Pre-warmed mailboxes. Available as an add-on, not in base plans. Renewal pricing for pre-warmed inventory is not on the main pricing page.
- 50+ outreach tool integrations. Instantly, Smartlead, ReachInbox, Reply, Lemlist, Salesforge, and others.
- API access. Pro plan only at $299/mo. Starter and Growth plans cannot use the API.
- AI tooling. Domain name generator, mailbox name generator, profile image generator. Useful for spinning up brand-adjacent identities.
- Placement test credits. 3 to 30 free credits per month depending on plan.
Zapmail pricing
Three monthly tiers, with quarterly and yearly options that drop the per-mailbox cost further:
- Starter: $39/mo, 10 Google mailboxes included, additional mailboxes at $3.50 each.
- Growth: $99/mo, 30 Google mailboxes, $3.25 per extra. Marketed as the most popular plan.
- Pro: $299/mo, 100 Google mailboxes, $3.00 per extra. Priority support and API access.
- Annual: Two months free brings the effective rate to roughly $2.50 per mailbox at the top tier.
Microsoft 365 mailboxes are not included in the headline plan price. Pre-warmed mailboxes are an additional purchase. Domains are sold separately starting at $13 for .com extensions.
What Zapmail users have flagged
The Zapmail TrustPilot page is mostly positive, but the critical reviews keep returning to the same issue: the underlying supply chain. One user, posting under "Cem" in June 2025, summarised what a Reddit thread of cold email operators had already documented:
A 1-star Trustpilot review claiming Zapmail resells Indian Google Workspace inboxes - the same critique surfaced in a Reddit reverse-engineering thread cited across the cold email community.
The mechanism described is straightforward: Google Workspace seats are sourced through Reseller Club India at roughly $2 each and resold at $3 to $3.50. The Reddit walk-through tells you how to verify it - request admin access to a Zapmail-provisioned workspace, open Google Admin Console, navigate to Billing, and you'll see the reseller relationship. Whether this affects deliverability is debated. The more documented complaint is that Microsoft 365 mailboxes provisioned through Zapmail disconnect more often than Google ones, which several r/coldemail posts have logged over the past year.
Zapmail is a reasonable starting point for a freelancer or small agency at 10 to 30 mailboxes who wants the cheapest possible Google Workspace seats and is comfortable with a reseller model. At higher volume and on Microsoft 365 specifically, the trade-offs start to add up.
Maildoso overview
Maildoso is a cold email mailbox provider that sells SMTP mailboxes and Google Workspace mailboxes together, with a focus on volume economics. The homepage cites 10M+ emails sent per day, 400k+ mailboxes managed, and a 4.7 G2 rating across 179 reviews. Maildoso is positioned as the budget pick for agencies running outreach at scale, with claims of 95%+ deliverability and a self-healing mailbox system that pauses burned inboxes for 14 days before bringing them back into rotation.
What Maildoso includes
- SMTP + Google Workspace combo plans. Microsoft 365 is not currently offered. Maildoso has said MS365 support is on the roadmap.
- Automated DNS. SPF, DKIM, DMARC configured per domain at provisioning.
- 35 data centers with IP rotation. Shared SMTP infrastructure that rotates sending IPs to reduce per-IP exposure.
- Self-healing mailboxes. Burned mailboxes pause for a 14-day cool-down and then resume.
- Inbox placement tests every 3 days. Each mailbox gets an automated placement check, with a health score visible in the dashboard.
- Master inbox + domain forwarding. All replies funnel into one centralised inbox so you don't have to log into every mailbox individually.
- Free domains on quarterly plans. Maildoso bundles domain registration into the plan cost, which is a real saving if you'd otherwise pay $12-$15 per .com per year.
- 30-day money-back guarantee on quarterly plans. The only refund window the three providers in this comparison offer at the time of writing.
Maildoso pricing
Maildoso's current pricing is built around combo plans that pair SMTP and Google Workspace mailboxes in equal numbers:
- 15 GW + 15 SMTP: $90/mo, $3 per SMTP and GW, 6 domains required.
- 35 GW + 35 SMTP: $175/mo, $2.50 per SMTP and GW, 14 domains required.
- 150 GW + 150 SMTP: $675/mo, $2 per SMTP and $2.50 per GW, 60 domains required.
Pure SMTP plans are also available at lower per-mailbox prices. Quarterly billing is required for the lowest rates, which means a 3-month commitment paid upfront before you can verify deliverability on your own list. The 30-day money-back guarantee softens that, but it's still a cash flow hit at the higher tiers (a 150-mailbox plan is $2,025 upfront).
What Maildoso users have flagged
I won't paste a critical review screenshot here because Maildoso does not have a TrustPilot page and the substantive critical reviews live on G2, which is not crawlable for screenshot purposes. What I can do is summarise the patterns that show up across multiple independent review aggregators (Prospeo, Mailforge, Puzzle Inbox, Woodpecker's blog, and a community thread on r/coldemail):
- Burned domains replaced with low-trust TLDs. When a domain gets flagged, Maildoso has been documented as substituting .xyz or .click replacements rather than .com. Spamhaus and DomainTools both list .xyz and .click in the top 20 most-spam-abused TLDs, which means a replacement on those extensions usually ends up flagged again within weeks.
- Deliverability variance on SMTP. Independent placement tests have measured Maildoso SMTP inbox placement at 85-90% versus 92-95% on Google Workspace direct, with batch suspensions when shared infrastructure gets flagged.
- Forced quarterly billing. No monthly plan at the lowest per-mailbox rates. Several G2 reviews flag this as the dealbreaker for teams who want to test before committing.
- Support response variability. Onboarding support is consistently rated highly. Critical reviews on G2 cite delayed responses on persistent issues, including one reviewer reporting a 50+ day unresolved support ticket.
Maildoso works for agencies that already know what they're doing, have clean prospect data, and want the cheapest combo of SMTP + Google Workspace at high volume. It does not work for teams that want Microsoft 365, want monthly billing, or care about SOC 2.
Primeforge overview
Primeforge is the email infrastructure product in the Forge Stack. It provisions real Google Workspace and Microsoft 365 mailboxes configured specifically for cold outreach, with automated DNS, US-based IPs, and a 30-minute setup time. The positioning line on the homepage is the clearest summary I've seen of what the product is: "Cold email mailboxes built for deliverability, not daily use." These aren't repurposed personal Gmail accounts and they're not EDU-license workarounds. They're full Google Workspace and Microsoft 365 mailboxes with full domain and mailbox ownership.
What Primeforge includes
- Real Google Workspace + real Microsoft 365. No EDU tricks. No grey-market reseller chains. No fragile loopholes that break when Google updates its policies.
- US-based IPs on every mailbox. Matters for US/EU outreach where non-US sending IPs are a documented spam-filter signal.
- 30-minute setup. From signup to sending in half an hour. The competitor pages quote 5-10 minutes, but those numbers reference the technical provisioning only - they don't include the time you'd then spend wiring DNS and reconciling tracking domains by hand.
- Automated DNS configuration. SPF, DKIM, DMARC, and custom tracking domains set up automatically per domain. Bulk DNS updates available across multiple domains at once.
- Pre-warmed mailboxes. Available as standard, not as a separately-purchased add-on.
- Mailbox profile pictures and GIFs at scale. Personalised mailbox identities configured out of the box.
- ESP Matching. The deliverability tactic of sending from the same email provider as your recipient (Workspace to Workspace, MS365 to MS365). Primeforge is the only provider in this comparison that offers both ESPs natively under one account, which makes ESP Matching practical to actually run.
- API, MCP server, and CLI. Programmatic access included in every plan. The MCP server lets Claude, Cursor, or any MCP-compatible assistant provision mailboxes and run DNS checks from a chat interface.
- SOC 2 compliant. Neither Zapmail nor Maildoso publish a SOC 2 certification.
- Multi-workspace organisation. Separate workspaces per client or campaign, with bulk operations across them.
- Works with any sending software. Primeforge is not locked to Salesforge. The mailboxes plug into Instantly, Smartlead, Lemlist, Woodpecker, Salesforge, or any other sequencer via standard OAuth.
Primeforge in the Forge Stack
Primeforge is one of three infrastructure products in the Forge Stack, and the stack as a whole is what makes it interesting at scale:
- Mailforge - shared IP infrastructure at $2 to $3 per mailbox per month. Cheaper than Primeforge, but uses a shared IP pool rather than real Workspace/MS365 mailboxes.
- Infraforge - private dedicated IPs at $3 to $4 per mailbox per month. For senders who need full IP control and have the volume to justify it.
- Warmforge - email warm-up and deliverability monitoring. Included free and unlimited with every Salesforge subscription. As a standalone product, it works with any Primeforge mailbox.
The most common hybrid stack I see in practice is Primeforge for the ESP-matched mailboxes, Mailforge or Infraforge for additional sending volume, and Warmforge across the whole thing. That diversifies the infrastructure footprint without giving up the compliance and quality of real Google Workspace and Microsoft 365 mailboxes for the primary touchpoints.
Primeforge pricing
Per-mailbox pricing scales from $4.50 down to $3.50 per mailbox per month based on volume. Billing is monthly or annual, with two months free on annual billing. Per Primeforge's own numbers, this works out to roughly 46% cheaper than buying Google Workspace direct from Google and roughly 25% cheaper than Microsoft 365 direct from Microsoft. There's no quarterly lock-in, and no separate add-on cost for pre-warmed mailboxes when you need them.
Honest limitations
- Per-mailbox cost is higher than Maildoso's lowest-tier combo plans and higher than Zapmail's Pro tier at scale. If your only constraint is "cheapest possible per mailbox," look at Mailforge inside the Forge Stack rather than the external alternatives.
- No free trial. You can book a demo and walk through the dashboard, but you'll need to commit to a paid plan to spin up your first mailbox.
- Domain purchases are billed separately. Domains aren't bundled into the per-mailbox price the way Maildoso bundles them on quarterly plans.
Start with Primeforge - real Google + Microsoft mailboxes in 30 minutes
Head-to-head: how the three compare
1. Mailbox quality and provider mix
Primeforge is the only one of the three that provisions both real Google Workspace and real Microsoft 365 mailboxes natively, under your ownership, on US-based IPs. Zapmail offers Microsoft 365 but sells it separately and has documented disconnect issues. Maildoso doesn't offer Microsoft 365 at all - it's SMTP plus Google Workspace, and Maildoso's own team has said MS365 is on the roadmap rather than shipped.
This matters more than it sounds. ESP Matching, where you send from the same email provider your recipient uses (Workspace to Workspace, MS365 to MS365), is a documented inbox-placement lever. If half your prospect list is on Outlook and you're sending entirely from Google Workspace mailboxes, you're handicapping yourself before the campaign starts. Primeforge gives you both ESPs in one account. Zapmail makes you pay separately for MS365. Maildoso doesn't give you the option.
2. Deliverability infrastructure
Maildoso runs shared SMTP infrastructure with IP rotation across 35 data centers. Shared SMTP gives you cheaper per-mailbox economics, but it also means your sender reputation is partly a function of whoever else is sending through the same infrastructure that day. That's the mechanism behind the "batch suspensions" and random deliverability drops that show up in Maildoso reviews.
Zapmail's deliverability is constrained by the underlying Google Workspace and Microsoft 365 accounts. Workspace-level isolation (one domain per workspace) limits collateral damage when a domain gets flagged, which is a structural improvement over providers that lump multiple domains under one workspace. The unresolved issue is the supply chain - if the accounts themselves are sourced through a non-US reseller and provisioned at scale, you're inheriting whatever reputation that supply chain has.
Primeforge sits on real Google Workspace and Microsoft 365 accounts with US-based IPs, full automated DNS, and SOC 2 compliance. Paired with Warmforge for warm-up, you have a sender stack where every layer is accountable and observable - the mailbox provider, the DNS configuration, the warm-up environment. That's not a marketing claim, it's a topology: each component owns its piece, and if something goes wrong, you can isolate where.
3. Pricing structure and billing terms
Maildoso is the cheapest per mailbox at high volume, but it forces a 3-month upfront commitment to access those rates. A 150-mailbox plan costs $2,025 upfront. The 30-day money-back guarantee softens this, but it's still a cash flow concern at scale.
Zapmail is the cheapest at low volume. Starter at $39/mo for 10 mailboxes is the lowest entry point in this comparison. Monthly billing is available across all tiers. The catch is that Microsoft 365, pre-warmed accounts, and API access (Pro plan only) all live behind additional spend on top of the headline price.
Primeforge sits at the highest per-mailbox price but includes pre-warmed availability, both ESPs, API access on every plan, and SOC 2 compliance without surcharges. Annual billing offers two months free. There's no quarterly lock-in.
4. Warm-up and deliverability monitoring
Maildoso includes basic warm-up and runs inbox placement tests every 3 days per mailbox with a visible health score in the dashboard. This is genuinely useful and is the strongest feature of the product.
Zapmail does not include warm-up natively. You pair it with an external warm-up tool, which adds cost. Placement test credits are limited to 3 per month on Starter, 10 on Growth, 30 on Pro.
Primeforge is built to pair with Warmforge, which is the deliverability center of the Forge Stack. Warmforge is included free and unlimited with every Salesforge subscription, and runs across any mailbox you connect (Google Workspace, Microsoft 365, or any of the Forge infrastructure products). Heat Score™ monitoring per mailbox, automatic spam removal during warm-up, multilingual warm-up traffic, and the warm-up pool itself is curated to exclude external SMTP vendors. If you're running Primeforge mailboxes through Salesforge, Warmforge is at no extra cost. As a standalone product, it works the same with mailboxes connected to other sequencers.
5. Compliance, ownership, and supply chain
SOC 2 compliance: Primeforge yes, Zapmail no published certification, Maildoso no published certification. For B2B SaaS teams selling into regulated buyers, SOC 2 on the infrastructure side of your outbound stack matters when procurement starts asking questions.
Mailbox ownership: Primeforge gives you full domain and mailbox ownership. Zapmail's reseller chain (documented Indian sourcing for at least some seats) means the chain of custody for the underlying account is less transparent. Maildoso's SMTP mailboxes are shared infrastructure, and the Google Workspace accounts come through Maildoso's reseller relationship.
This is the layer most cold email comparisons skip. It's also the layer that determines whether your mailbox is still yours in 12 months when you want to migrate to a different sequencer, hand it to a client, or sell the underlying business with the deliverability assets intact. If you want to audit the rest of your infrastructure while you're here, Salesforge maintains a set of free deliverability and DNS tools (DKIM/SPF/DMARC checkers, blacklist lookups, placement tests) that work on any mailbox provider, not just Primeforge.
6. API and developer surfaces
Primeforge ships an API, an MCP server, and a CLI - all included in every plan. The MCP server is particularly useful for teams building AI SDR workflows; an MCP-compatible assistant can provision mailboxes, configure DNS, and pull placement reports from a chat interface.
Zapmail offers a headless API but gates it to the Pro plan at $299/mo. Maildoso offers an API across plans. Neither competitor offers an MCP server.
Pricing breakdown
Here's the per-mailbox math at three representative volumes. All numbers are from each vendor's published pricing as of May 2026.
| Volume | Primeforge | Zapmail (Google) | Maildoso (Combo) |
|---|---|---|---|
| 10 mailboxes / month | $45/mo at $4.50/mailbox | $39/mo (Starter, 10 GW) | $90/mo (15 GW + 15 SMTP minimum) |
| 30 mailboxes / month | $120-$135/mo | $99/mo (Growth, 30 GW) | $175/mo (35 GW + 35 SMTP, $525/quarter) |
| 100 mailboxes / month | $350-$400/mo at $3.50-$4/mailbox | $299/mo (Pro, 100 GW) | Not directly mapped; nearest tier is 150+150 at $675/mo ($2,025/quarter) |
| Microsoft 365 supported | Yes, same plan | Yes, sold separately | No |
| Pre-warmed available | Yes, no surcharge | Yes, separate purchase | No |
| Billing cycle | Monthly or annual | Monthly, quarterly, yearly | Quarterly only at lowest rates |
| Free trial | None; demo available | None; subscription required | None; 30-day money-back on quarterly |
Zapmail's published Workspace plans. Microsoft 365 and pre-warmed mailboxes are priced separately on top of these rates.
The reading on this: Zapmail has the lowest entry price at small volume. Maildoso has the lowest per-mailbox price at very high volume, paid quarterly upfront. Primeforge sits at a middle per-mailbox price that includes both ESPs, pre-warmed availability, SOC 2, and API access without per-feature surcharges. The "cheapest per mailbox" reading flips depending on what you actually need beyond the mailbox itself.
A worked example: an agency running 50 mailboxes across 25 domains for 5 client accounts, sending to a mix of Workspace and Outlook recipients. On Primeforge: roughly $200/mo for the mailboxes, ESPs matched on both sides, multi-workspace separation per client, SOC 2 to satisfy client procurement. On Zapmail Growth at the same scale: $99/mo plus the extra 20 mailboxes at $3.25, plus a separate purchase for the Outlook half of the list. On Maildoso 35+35 combo: $175/mo billed as $525/quarter, no MS365 option, shared SMTP risk. The headline price gap closes fast once you account for what each product actually includes.
Who should use which tool
You might consider Zapmail if:
- You're a solo operator or freelancer at 10 to 30 Google Workspace mailboxes and the headline $39/mo entry price matters more than supply chain transparency
- You want monthly billing and don't need Microsoft 365 mailboxes in the same account
- You're comfortable evaluating the reseller chain yourself and don't need SOC 2 compliance
You might consider Maildoso if:
- You're an agency running 50+ mailboxes purely in Google Workspace (no Microsoft 365 needs)
- Lowest possible per-mailbox cost at high volume is the dominant constraint, and you have the cash to commit quarterly
- You're comfortable with shared SMTP infrastructure risk and the documented pattern of low-trust TLD domain replacements
Choose Primeforge if:
- You need real Google Workspace and real Microsoft 365 mailboxes in one account, on US IPs, with full ownership of every domain and mailbox
- Your prospect list is mixed across both ESPs and you want ESP Matching to actually work
- You sell B2B into buyers who ask about SOC 2 compliance on your sender infrastructure
- You want monthly billing without quarterly lock-in, pre-warmed mailboxes without surcharges, and API access without a Pro-tier upgrade
- You're already running Salesforge, Mailforge, Infraforge, or Warmforge, or you're planning to - the native integration with the rest of the Forge Stack is meaningful when you go to scale past your first 50 mailboxes
Final verdict
Primeforge's positioning, on the homepage: real Google Workspace and Microsoft 365 mailboxes, US IPs, SOC 2, 30-minute setup. No EDU tricks, no resold inboxes, no quarterly lock-in.
Zapmail is a Google Workspace reseller with a documented supply chain question and a Microsoft 365 product that several reviewers have flagged as unreliable. Maildoso is a budget combo provider that bundles SMTP with Workspace, forces quarterly billing, and has a known pattern of replacing burned domains with low-trust TLDs. Both are usable. Neither is built for a team that wants compliant, deliverable mailboxes they can hand to their procurement team or scale past a hundred without rebuilding the stack.
For cold email mailbox infrastructure built for deliverability, Primeforge is the stronger choice. Real Google Workspace and Microsoft 365 mailboxes in one account, US-based IPs, SOC 2 compliance, automated DNS, pre-warmed availability without surcharges, and native integration with Warmforge warm-up and the rest of the Forge Stack. Per-mailbox cost lands at $4.50 down to $3.50 with monthly or annual billing.
One falsifiable benchmark: ChannelCrawler hit an 85.71% positive reply rate using the Forge Stack (Salesforge plus Infraforge plus Warmforge). UniteSync ran on Salesforge plus Mailforge plus Warmforge to an 85.26% positive reply rate and a $2.86 CAC. Both case studies are public on salesforge.ai. The infrastructure layer in both cases was a Forge Stack mailbox provider, not a budget reseller.
Start with Primeforge - real mailboxes ready in 30 minutes
Frequently asked questions
Is Primeforge better than Zapmail and Maildoso?
For real cold email deliverability at scale, Primeforge is the stronger choice. It provisions real Google Workspace and Microsoft 365 mailboxes on US IPs, includes pre-warmed mailboxes without surcharges, holds SOC 2 compliance, and integrates natively with Warmforge for warm-up. Zapmail and Maildoso both involve reseller chains and lack SOC 2 certification. The honest read: Zapmail is cheaper at 10-30 mailboxes if you only need Google Workspace, and Maildoso is cheaper at high volume if you can commit quarterly. Primeforge wins on compliance, ESP coverage, and ownership.
What's the main difference between Primeforge, Zapmail, and Maildoso?
The fundamental difference is in mailbox provenance. Primeforge provisions real Google Workspace and Microsoft 365 mailboxes that you own outright, on US-based IPs, with SOC 2 compliance. Zapmail resells Google Workspace and Microsoft 365 seats sourced through a third-party reseller chain (documented as Reseller Club India for at least some accounts). Maildoso sells shared SMTP mailboxes paired with Google Workspace, with shared infrastructure risk and no Microsoft 365 option. The cheapest entry point is Zapmail at $39/mo for 10 mailboxes. The most compliant and ownership-transparent option is Primeforge.
Which is cheapest - Primeforge, Zapmail, or Maildoso?
It depends on volume and billing flexibility. Zapmail Starter at $39/mo for 10 Google Workspace mailboxes is the lowest entry point. Maildoso is cheapest per mailbox at 100+ mailboxes if you can commit quarterly (down to $2 per SMTP mailbox at 150+150 combo). Primeforge runs $4.50 down to $3.50 per mailbox per month with monthly or annual billing. When you factor in Microsoft 365, pre-warmed mailboxes, API access, and SOC 2 compliance (which Zapmail and Maildoso either charge extra for or don't offer), the effective comparison narrows considerably.
Does Maildoso support Microsoft 365 mailboxes?
No. Maildoso currently offers SMTP mailboxes and Google Workspace mailboxes only. Microsoft 365 support has been described as on the product roadmap but is not shipping at the time of writing. For teams that need to send from both ESPs, Primeforge is the only one of the three that offers real Google Workspace and real Microsoft 365 mailboxes natively in the same account.
Can I switch from Zapmail or Maildoso to Primeforge?
Yes. Primeforge supports domain transfers in and out, and the mailboxes work with any sending software (Salesforge, Instantly, Smartlead, Lemlist, Reply, Woodpecker, or any other sequencer via OAuth). If you're moving from a reseller-provisioned account, the cleanest migration path is to spin up fresh Primeforge mailboxes on new domains, warm them via Warmforge for 14 days, and migrate sending volume over rather than trying to transfer existing mailboxes that may have inherited reputation issues from the prior infrastructure. The Salesforge blog has a longer write-up on cold email infrastructure migration if you want the full playbook.
Does Primeforge include warm-up?
Primeforge pairs natively with Warmforge, the Forge Stack's warm-up and deliverability center. Warmforge is included free and unlimited with every Salesforge subscription. As a standalone product, it works with any Primeforge mailbox or any other mailbox connected via Google Workspace or Microsoft Outlook. Warmforge uses a curated pool of real Workspace and Microsoft 365 mailboxes for warm-up traffic, which is documented as higher-quality than the warm-up pools used by some external warm-up tools that include external SMTP vendors.
Who is Zapmail best for?
Zapmail fits solo operators, freelancers, and small agencies running cold outreach at 10 to 30 Google Workspace mailboxes who want the lowest possible monthly entry point and don't need Microsoft 365 in the same account. The product is functional at that scale and the workspace-level isolation model is a structural advantage over providers that lump multiple domains together. Beyond that scale, or when Microsoft 365 enters the picture, the limitations and the supply chain questions start to matter more.
Who is Maildoso best for?
Maildoso fits agencies and lead generation teams that need 50+ Google Workspace mailboxes at the cheapest possible per-mailbox rate, are comfortable committing quarterly, and don't need Microsoft 365. The Auto-Heal feature and 3-day placement testing are real value-adds for high-volume operators. The trade-offs are shared SMTP infrastructure risk, the documented .xyz/.click domain replacement pattern, and the absence of SOC 2 compliance.
Does Primeforge offer a free trial?
Primeforge does not offer a self-serve free trial. You can book a demo to walk through the dashboard and the mailbox provisioning flow before committing. Once you're set up, the standard plan terms apply (monthly or annual billing, with two months free on annual). The lack of a free trial is one of the honest limitations of the product, though it's a limitation shared with both competitors in this comparison.
Is Primeforge part of Salesforge?
Primeforge is one of the products in the Forge Stack, alongside Salesforge (sending platform), Mailforge (shared IP infrastructure), Infraforge (dedicated IPs), Warmforge (warm-up), and Leadsforge (lead search). Each product is sold separately and can be used independently, but they integrate natively with each other at the system level. Primeforge mailboxes plug into Salesforge in one click, and Warmforge runs across any Primeforge mailbox without configuration.
