Zapmail is a Google Workspace and Microsoft 365 mailbox provider priced from $39/mo for 10 inboxes, with workspace-level isolation and a Pro tier at $299/mo. Maildoso is a cheaper SMTP-and-Google-Workspace shop starting at $75/mo for 30 SMTP mailboxes, with quarterly upfront commitments and a built-in warm-up tool sold separately.
For cold email infrastructure that actually scales, Mailforge is the stronger choice. $3 to $2 per mailbox per month, automated DMARC/SPF/DKIM setup in 5 minutes, free unlimited Warmforge warm-up bundled in, and a native path to dedicated IPs through Infraforge or real Google Workspace and Microsoft 365 inboxes through Primeforge when you outgrow shared infrastructure.
I have spent the last few years setting up cold email infrastructure for outbound teams - my own and other people's. Mailforge, Zapmail and Maildoso show up in every shortlist, but they solve the problem in very different ways, and the right choice depends almost entirely on how you plan to scale.
This is a head-to-head on what each one actually gives you for the money. I will cover setup speed, IP model, deliverability tools, warm-up, integrations, and the parts of the bill that don't show up on the pricing page. If you are evaluating Mailforge against either of these two, you will find the case for it stronger than most comparison pages let on.
Quick-glance comparison
| Feature | Mailforge | Zapmail | Maildoso |
|---|---|---|---|
| Infrastructure model | Distributed shared IPs | Google Workspace + MS365 reseller | SMTP shared IPs + Google Workspace |
| Entry price | $3 to $2 / mailbox / month | $39/mo (10 mailboxes) | $75/mo (30 SMTP mailboxes) |
| Mailbox cost at 100+ | ~$2.50 / mailbox | $3.00 / mailbox (Pro) | $1.90 - $2.50 / mailbox |
| Setup time | 5 minutes | ~10 minutes | ~15 minutes |
| Automated DNS (SPF/DKIM/DMARC) | Yes, every domain | Yes | Yes |
| Free warm-up included | Yes - unlimited Warmforge | No - pre-warmed mailboxes sold separately | No - native warm-up is a paid add-on |
| Pre-warmed mailboxes | Available via Infraforge | Yes - separate purchase | No |
| Dedicated IP option | Yes - via Infraforge | No | No |
| SSL & domain masking | Yes (add-on) | ZapShield (separate feature) | Yes (CDT) |
| Bulk DNS updates | Yes | Yes | Limited |
| Multiple workspaces | Yes | Yes - 1 domain per workspace | Yes - 1 domain per workspace |
| Billing model | Monthly or annual | Monthly, quarterly or annual | Monthly or quarterly (upfront) |
| SOC 2 compliant | Yes | Not listed | Not listed |
| Cost per 200 mailboxes | $484 / month | ~$600 / month | ~$380 / month (SMTP) |
| Best for | Agencies and teams scaling from 50 to 2,500+ mailboxes | Freelancers and small agencies on Google Workspace only | Budget operators willing to commit quarterly |
Zapmail overview
Zapmail is a Google Workspace and Microsoft 365 reseller built by Outbox Labs Inc. The pitch on their homepage: 1M+ mailboxes set up, 330k+ domains managed, 5-minute average setup, and a 4.5 Trustpilot score. The product is essentially provisioning automation - Zapmail signs you up for real Google or Microsoft accounts on US/EU IPs, configures DNS, names your mailboxes with AI, and exports the credentials to your outreach tool of choice.
Zapmail core features
- Real Google Workspace and Microsoft 365 mailboxes with US or EU IP addresses
- Automated DNS - SPF, DKIM, DMARC and custom tracking domains configured on signup
- Workspace-level isolation - one domain per Google or Microsoft workspace, which limits cross-contamination risk
- OAuth connection to 50+ outreach tools (Instantly, Smartlead, Reachinbox, Reply, Lemlist and others)
- Pre-warmed mailboxes sold as a separate purchase, not included in the workspace plans
- AI helpers - Instant Domain Genie (domain suggestions), Smart Mailbox Namer, Persona Snapshots for profile pictures
- ZapShield and Placement Test as separately-listed deliverability features
- Headless API for programmatic mailbox provisioning, gated to the Pro plan
Zapmail pricing
Three monthly plans on the Workspaces tier:
- Starter: $39/mo - 10 Google mailboxes, $3.50 per additional mailbox, 3 placement test credits, 3 AI Insights credits
- Growth: $99/mo - 30 Google mailboxes, $3.25 per additional mailbox, 10 placement tests, 10 AI Insights credits
- Pro: $299/mo - 100 Google mailboxes, $3.00 per additional mailbox, priority support, API access, 30 placement tests
Annual billing on Zapmail's Pro plan brings effective per-mailbox cost down to around $2.50 with "2 months free." Microsoft 365 mailboxes and pre-warmed mailboxes are separate add-on tiers, not bundled into the base plan price.
Who Zapmail fits
Freelancers and small agencies running outbound on Google Workspace specifically. The Starter plan at $39/mo is one of the cheapest entry points for legitimate Google mailboxes, and the AI helpers and OAuth integrations make the first mailbox-to-campaign flow genuinely fast for non-technical operators.
Honest limitations
- No bundled warm-up - pre-warmed mailboxes are a separate purchase; otherwise you handle warm-up in your sequencer
- No dedicated IP option - you are renting space on Google's shared pool, same as everyone else
- API access is Pro-plan only ($299/mo entry)
- SOC 2 certification is not advertised on their site
- Some 1-star Trustpilot reviews flag billing and IP location complaints. The one below is from March 2026:
That review is one of a small number of 1-star posts in an otherwise 4.5-star pool, so weigh it accordingly - but the deliverability claim about IP geography is the kind of thing worth verifying directly with their support before committing to an annual plan.
Maildoso overview
Maildoso is operated by BacklinkSwappers Inc. out of San Francisco. The headline numbers from their homepage: 10M+ emails sent per day, 4.7 G2 rating across 179 reviews, 400k+ mailboxes managed, "Trusted by 6,000+ companies." The product is built around two infrastructure types: SMTP mailboxes (shared IPs, cheapest tier) and Google Workspace mailboxes (for sending to Gmail and other personal email providers).
Maildoso core features
- SMTP mailboxes starting at $1.80/mailbox/mo on the highest-volume quarterly tier - among the cheapest per-mailbox prices on the market
- Google Workspace mailboxes for B2C and Gmail-targeted outreach, sold in Combo plans with SMTP
- Automated SPF, DKIM, DMARC on setup
- IP rotation across multiple IP addresses on SMTP plans
- Inbox placement tests every 3 days, included
- GCDT (Global Custom Domain Tracking) - their SSL/masking feature for links
- Self-healing mailboxes - burned accounts get auto-paused for 14 days, then rotated back in
- 1 workspace = 1 domain isolation, same architectural choice as Zapmail
- 30-day money-back guarantee on mailboxes
- Public API at developers.maildoso.com
- Microsoft mailboxes are on their roadmap, not currently available
Maildoso pricing
Three pricing tracks. The structure is denser than the other two:
- Monthly Combo (SMTP + Google Workspace): $90/mo for 15+15, $175/mo for 35+35, $675/mo for 150+150
- Monthly SMTP only: $75/mo for 30 mailboxes, $158/mo for 70, $570/mo for 300
- Quarterly SMTP: $299/qtr for 32 mailboxes (8 domains free), $499/qtr for 68 (17 free), $2,199/qtr for 400 (100 free)
Quarterly billing locks up working capital but bundles in free domain registration. Domain registration on monthly plans is $12/year.
Who Maildoso fits
Budget-conscious operators who need a lot of SMTP mailboxes fast and are comfortable committing to a quarterly cycle. The $1.80-$2.50 per mailbox range is a real edge if your campaigns can tolerate shared-pool risk.
Honest limitations
- Shared IP infrastructure - your deliverability depends on what other Maildoso users are doing on the same IP pool. Independent third-party reviews flag this as the structural risk
- No built-in warm-up bundled with the base plans - their native warm-up tool is an add-on, and independent reviewers have reported the all-in cost including warm-up landing at $18-$32 per inbox per month
- No Microsoft 365 yet - if your prospects are heavy on Outlook tenants and you want ESP matching, you cannot get it here
- Quarterly billing for SMTP - $299 minimum upfront commits you for 3 months on the smallest tier. A $2,199 commitment for the 400-mailbox tier is real cash flow exposure on day one
- Reddit and Prospeo's own customer reports describe domain blacklisting incidents where replacement domains were "unprofessional and spammy" and support response was slow during the crisis. One 100-mailbox test logged deliverability degradation at week 7-8 with roughly 12 SMTP mailboxes drifting to spam
- No dedicated IP option at any tier
- SOC 2 certification is not advertised
Mailforge overview
Mailforge is the distributed email infrastructure product inside the Forge Stack. It is purpose-built for cold outreach: shared IP pool optimized for sending volume, automated DNS at the per-domain level, and a free unlimited warm-up layer through Warmforge that competitors charge for or skip entirely. Used by 10,000+ businesses from solo operators to Fortune 500, with a 4.9 G2 rating on the product page.
Mailforge core features
- 5-minute setup with automated DMARC, SPF, DKIM and custom domain tracking on every domain
- Bulk DNS updates across hundreds of domains from one screen
- Domain transferring in or out of Mailforge with no friction
- Multiple workspaces for agency multi-client management
- SSL & Domain Masking add-on to protect your primary domain while running branded tracking
- Free unlimited Warmforge warm-up bundled in - premium-by-default pool of real Google Workspace and Microsoft 365 mailboxes, no recycled accounts, multilingual traffic, Heat Score monitoring
- Works with any sending software - Salesforge, Instantly, Smartlead, Reachinbox, your own SMTP scripts
- API, MCP server, and CLI for programmatic control - the same CLI runs the whole Forge Stack
- SOC 2 compliant infrastructure
- Native upgrade path to Infraforge for dedicated IPs and pre-warmed mailboxes, or to Primeforge for real Google Workspace and Microsoft 365 mailboxes - all on the same login
The Forge Stack context
Mailforge is one layer. The reason it punches above its price band is that the rest of the stack picks up where shared infrastructure stops making sense. Need dedicated IPs to escape the shared pool? Infraforge runs at $4 to $3 per mailbox. Need real Google Workspace and Microsoft 365 mailboxes for ESP matching? Primeforge at $4.50 to $3.50 per mailbox. Need warm-up monitoring with placement testing and Heat Score reporting? Warmforge is bundled in. None of that is a separate vendor relationship.
Mailforge pricing
- $3 per mailbox at the entry tier, scaling down to $2 per mailbox at higher volumes
- $484 per month for 200 mailboxes - compared to $1,680/mo for the equivalent Google Workspace direct, or $1,200/mo for Microsoft 365
- No quarterly upfront commitment - monthly or annual billing
- No warm-up paywall - Warmforge is free and unlimited
- Domains can be transferred in for free or purchased through the app
Who Mailforge fits
Agencies running 30+ clients on a unified stack. Sales teams scaling from 50 to 500 to 2,500+ mailboxes. Growth teams running multi-domain outbound where bulk DNS management and free warm-up materially change the unit economics. Anyone who wants infrastructure they don't have to babysit and who values the option to bolt dedicated IPs onto the same workspace later.
Honest limitations
- Shared IP pool at the Mailforge tier - if you need fully isolated IP reputation, Infraforge is the path inside the same stack
- No free trial - email infrastructure requires actual paid mailboxes to exercise
- Not the absolute cheapest - Maildoso's SMTP tier at $1.80/mailbox undercuts on raw price if you don't need the warm-up, SOC 2 compliance, or the stack upgrade path
in Action
Head-to-head: feature comparison
Setup speed and DNS automation
All three automate the technical setup, but the timings and the depth differ. Mailforge gets domains and mailboxes live in roughly 5 minutes with DMARC, SPF, DKIM and custom tracking domains configured to industry best practice. Zapmail's own homepage cites a 5-minute average and the comparison table on their site claims 10 minutes for OAuth-connected Google or Microsoft workspaces. Maildoso lists a 15-minute setup target with SPF, DKIM, DMARC auto-configured.
The practical difference shows up in bulk operations. Mailforge has bulk DNS updates baked into the app for managing hundreds of domains at once. Zapmail and Maildoso both lean on per-workspace operations - fine for 30 mailboxes, slower for 300.
IP infrastructure and the shared-pool risk
This is the part that separates the three the most. Zapmail puts you on Google's or Microsoft's shared sending pools by way of real Workspace and 365 accounts - your reputation rides on what Google and Microsoft decide, with workspace-level isolation as the architectural guardrail. Maildoso runs SMTP mailboxes on its own shared IPs with IP rotation, plus Google Workspace as a separate product line. Mailforge uses distributed shared IPs designed specifically for cold outreach, with the option to upgrade to dedicated IPs on Infraforge without changing vendor.
Shared IPs are not bad - they are the right answer for most volumes. The point is what happens when you outgrow them. With Zapmail, your only escape is moving providers. With Maildoso, same problem - they have no dedicated IP option at any tier. With Mailforge, the upgrade is a tab inside the same workspace.
Warm-up: bundled vs paid add-on
Mailforge includes free unlimited warm-up through Warmforge. The warm-up pool is curated - aged accounts only, no recycled inboxes, dominated by real Google Workspace and Microsoft 365 mailboxes with multilingual traffic. Heat Score monitoring is built in, target 97+.
Zapmail does not bundle warm-up. Their answer is pre-warmed mailboxes sold as a separate purchase tier, or you handle warm-up in your sequencer of choice. Maildoso's base plans also exclude warm-up - they offer a native warm-up tool as an add-on, and independent reviews place the effective all-in cost including warm-up between $18 and $32 per inbox per month, which collapses the headline-price advantage.
Pricing scalability
At low volume Maildoso wins on raw price - $75/mo for 30 SMTP mailboxes is the cheapest entry in this comparison. At medium volume the three are roughly comparable per mailbox. At high volume the comparison gets interesting.
200 mailboxes on Mailforge: $484/mo, no warm-up surcharge, no quarterly upfront. 200 mailboxes on Zapmail Pro plus 100 add-ons at $3.00 each: roughly $600/mo, plus pre-warmed mailbox costs if you want them. 200 mailboxes on Maildoso SMTP: around $380/mo on the 300-mailbox SMTP tier, but that's billed as $570/mo for 300 SMTP and committed for the cycle, and warm-up is extra.
The thing the spreadsheets miss is the dedicated-IP escape valve. If you cross the threshold where shared pools stop working, Mailforge gives you Infraforge at $4 to $3 per mailbox on the same login. Zapmail and Maildoso don't have that path.
Integrations and the broader stack
All three connect to the usual outreach tools - Instantly, Smartlead, Reachinbox, Reply, Lemlist. Zapmail and Maildoso advertise 50+ integrations. Mailforge "works with any sending software" because that's the entire pitch of distributed infrastructure - you bring your sequencer, Mailforge handles the inboxes.
Where Mailforge pulls ahead is the in-house stack. Leadsforge for lead search across 500M+ contacts, Agent Frank as the AI SDR, Salesforge for execution, and Primebox as the unified inbox - all native, single login. Zapmail and Maildoso are points on a stack you have to assemble.
Mailbox provider variety
Zapmail offers Google Workspace and Microsoft 365 (Microsoft is a separate tier). Maildoso offers SMTP and Google Workspace, with Microsoft listed as on their roadmap. Mailforge by itself is shared SMTP infrastructure, but the Forge Stack includes Primeforge for real Google Workspace and Microsoft 365 mailboxes on US IPs, configured for cold outreach with profile pictures and tracking domains - $4.50 to $3.50 per mailbox. ESP matching across both providers on the same login.
Compliance and trust signals
Mailforge is SOC 2 compliant - publicly stated, badged across the Forge properties. Neither Zapmail nor Maildoso advertise SOC 2 certification on their main marketing surface. For agencies with client-side procurement processes that ask for SOC 2 attestations, this matters more than a feature checklist suggests.
Pricing comparison
Headline numbers side by side:
| Plan / tier | Monthly price | Mailboxes | Effective per mailbox |
|---|---|---|---|
| Mailforge entry | From $3 / mailbox | Pay per mailbox | $3.00 |
| Mailforge at scale | $484/mo | 200 | $2.42 |
| Zapmail Starter | $39/mo | 10 | $3.90 |
| Zapmail Growth | $99/mo | 30 | $3.30 |
| Zapmail Pro | $299/mo | 100 | $2.99 |
| Zapmail Pro (annual) | ~$249/mo | 100 | ~$2.50 |
| Maildoso SMTP small | $75/mo | 30 | $2.50 |
| Maildoso SMTP medium | $158/mo | 70 | $2.26 |
| Maildoso SMTP large | $570/mo | 300 | $1.90 |
| Maildoso Combo (GW+SMTP) | $675/mo | 300 (150 each) | $2.25 |
| Maildoso quarterly SMTP | $2,199/qtr ($733/mo) | 400 (100 domains free) | $1.83 |
Scenario: 100 mailboxes per month
The most common volume bracket I see for agencies running 5-10 client campaigns:
- Mailforge: roughly $250/mo at $2.50/mailbox, plus free unlimited Warmforge warm-up bundled
- Zapmail Pro: $299/mo monthly or about $249/mo annual, no warm-up included
- Maildoso SMTP: $158/mo for 70 mailboxes, or $570/mo for 300 - the 100-mailbox bracket doesn't exist as a discrete tier, so you over-buy
For the same volume, Mailforge ends up cheaper than Zapmail Pro on monthly billing and roughly even on annual. Against Maildoso, you pay more on raw mailbox cost - but you avoid the quarterly commitment, you get free warm-up, and you keep the option to escalate to dedicated IPs without switching vendor.
Who should use which tool
- Your outbound runs exclusively on Google Workspace or Microsoft 365 mailboxes and ESP matching matters more than infrastructure flexibility
- You are a freelancer or 1-2 person agency starting at 10-30 mailboxes and want the cheapest entry point ($39/mo Starter) on legitimate Google accounts
- The Pro plan's annual rate around $2.50/mailbox and built-in API access work for your scale and you don't need SOC 2 certification
- Per-mailbox cost is the dominant variable in your decision and you can absorb shared-IP risk at scale
- You are comfortable committing to quarterly billing - $299 upfront on the smallest SMTP tier, $2,199 on the 400-mailbox tier
- You do not need Microsoft 365 mailboxes (their roadmap item, not yet shipping) and you plan to run your own warm-up tool separately
- You are running outbound for an agency or in-house team scaling from 50 to 500+ mailboxes and you want one provider for the whole journey
- You want free unlimited Warmforge warm-up bundled in - the only one of the three that includes premium-by-default warm-up at no extra cost
- You need the option to move to dedicated IPs (Infraforge) or real Google Workspace and Microsoft 365 mailboxes (Primeforge) without changing vendors
- You manage clients or projects in separate workspaces and need bulk DNS updates across hundreds of domains
- You sell into procurement processes that ask for SOC 2 attestation
Final verdict
Zapmail and Maildoso solve narrow problems well. Zapmail is a clean Google Workspace and Microsoft 365 reseller for teams that already know they want those providers and only those providers. Maildoso is the cheapest SMTP infrastructure on the market if you can absorb quarterly billing and shared-pool risk and don't mind sourcing warm-up separately.
For cold email infrastructure that scales with you, Mailforge is the stronger choice. $3 to $2 per mailbox, automated DNS on every domain in 5 minutes, free unlimited Warmforge warm-up bundled in, SOC 2 compliance, and a native upgrade path to dedicated IPs or real Google Workspace and Microsoft 365 mailboxes on the same login - none of the alternatives offer that combination at any price.
One falsifiable benchmark: SalesCaptain migrated 70% of their cold email infrastructure to Mailforge and now runs 280+ active sending domains and 600+ dedicated cold email mailboxes for 30+ client accounts, holding 97-100% mailbox reputation scores across the board. The full case study is public.
Start with Mailforge today →