Line by line
| Feature | Inboxkit | Mailerr |
|---|---|---|
| Mailboxes | Official, paid Google Workspace and Microsoft 365, plus Azure | Not stated: no Google, Microsoft or server type named |
| Price | $3 a mailbox, or $2.50 on annual billing | Plans: $40 for 10, $100 for 30, $360 for 100 |
| Extra mailboxes | Same $3, one at a time | $4 on Business, $3.50 on Enterprise |
| Domains | Buy domains or connect your own in one click | Custom, or bought at $14 to $16 a year; 3, 10 or 35 a plan |
| Microsoft volume | Azure: $30 a tenant for up to 100 mailboxes | Not listed |
| Sequencer export | One-click export to 24+ sequencers | CSV for Instantly, Smartlead or other tools |
| Claude Code / Codex (MCP) | Remote MCP server, connects to Claude Code and Codex | Not listed |
| API | Full REST API with webhooks on every account, 119 endpoints | No public API docs |
| Warmup | Add-on: 14 days on an isolated network, $3 a mailbox | Included in every plan; advanced on Enterprise |
| Monitoring | InfraGuard add-on, every six hours: blacklists, DNS, bounces, placement, auto-pause | Continuous checks for blacklists, spam reports and bounces, per its FAQ |
| Support | 24/7 on Slack, in-app chat and email | Channel and hours not stated |
Competitor details from public pages, checked 28 Oct 2026. Sources: Mailerr homepage and FAQ (mailerr.co); Mailerr pricing (mailerr.co); Mailerr terms of use (mailerr.co); Inboxkit pricing.
Competitor offers can change after that date. Trademarks belong to their owners.
Prices at common volumes
| Mailboxes | Inboxkit, monthly | Inboxkit, annual | Mailerr |
|---|---|---|---|
| 10mailboxesMailerr Solopreneur plan | Inboxkit, monthly$30 | Inboxkit, annual$25 | Mailerr$40 |
| 30mailboxesMailerr Business plan | Inboxkit, monthly$90 | Inboxkit, annual$75 | Mailerr$100 |
| 100mailboxesMailerr Enterprise plan | Inboxkit, monthly$300 | Inboxkit, annual$250 | Mailerr$360 |
Mailerr’s plans include warmup and lead validation. Add our $3 warmup and Mailerr costs less at every size above. Ours buys official Google or Microsoft seats, one mailbox at a time.
Mailboxes only, monthly billing. Mailerr sells plans of 10, 30 or 100 accounts, capped at 3, 10 or 35 domains. Its domains are $14 to $16 a year. Annual billing takes 5% off its plans.
Mailerr pricing against Inboxkit
Mailerr sells three plans. Solopreneur is $40 a month for 10 accounts and 3 domains. Business is $100 for 30 accounts and 10 domains, and Enterprise is $360 for 100 accounts and 35 domains. Extra inboxes cost $4 on Business and $3.50 on Enterprise.
Domains are extra, at $14 to $16 a year. Annual billing takes 5% off the plans. Warmup and lead validation are included in every plan.
Inboxkit is $3 a mailbox on monthly billing, or $2.50 on annual, with no plan. At 100 mailboxes that is $300 against Mailerr’s $360. Our warmup is a $3 add-on, so with warmup Mailerr costs less.
What Mailerr mailboxes are
Mailerr’s site does not say whether its mailboxes are Google Workspace, Microsoft 365 or its own mail servers. Its FAQ mentions US-based IP addresses and admin access to manage your mailboxes.
Inboxkit sells official, paid Google Workspace and Microsoft 365 mailboxes at the same $3. Microsoft volume can run on Azure, where one tenant holds up to 100 mailboxes for $30 a month. Pre-warmed mailboxes are live in hours.
Mailerr setup, domains and sequencer export
Mailerr configures SPF, DKIM, DMARC and MX for you, and sells .com and over 10 other domain endings. It also supports custom domains. Each plan caps your domains at 3, 10 or 35. Mailboxes export as a CSV for Instantly, Smartlead or other tools.
Inboxkit completes orders in 30 to 120 minutes, automatically, with SPF, DKIM and DMARC configured. You buy domains or connect your own. Mailboxes export in one click to 24+ sequencers.
Mailerr warmup and monitoring
Every Mailerr plan includes warmup: basic on Solopreneur and Business, advanced on Enterprise. Its FAQ says it continuously monitors for blacklisting, spam reports and bounces. The site lists no inbox placement tests.
Inboxkit’s warmup is an add-on at $3 a mailbox and runs for 14 days on an isolated network. InfraGuard, also an add-on, checks blacklists, DNS, bounces and inbox placement every six hours. It has alerts, auto-pause and unlimited placement tests. Its first month is free.
Mailerr API, MCP and support
Mailerr’s site has no public API documentation and lists no MCP server. Every plan lists customer support, without naming a channel or hours.
Every Inboxkit account gets the full REST API, with 119 endpoints and webhooks, and a remote MCP server for Claude Code and Codex. Support runs 24/7 on Slack, in-app chat and email. Inboxkit is rated 4.7 out of 5 on G2 from 120 reviews.
Switch from Mailerr in four steps
Create a free account
Pay only for the mailboxes you add. No plan to pick first.
Buy or connect domains
Then add Google Workspace, Microsoft 365 or Azure mailboxes on them.
Export to your sequencer
One click to 24+ sequencers, including Smartlead and Instantly.
Run both side by side
Warm up here while Mailerr keeps sending. Move campaigns before your plan renews.
Questions about Mailerr
Is Mailerr legit?
Mailerr is run by OÜ Partnerway, a company registered in Estonia, at mailerr.co. Its site does not say whether its mailboxes are Google Workspace, Microsoft 365 or its own servers.
How does Mailerr pricing work?
Mailerr sells plans: $40 a month for 10 accounts, $100 for 30 and $360 for 100. Extra inboxes are $4 on Business and $3.50 on Enterprise. Domains cost $14 to $16 a year.
Is Inboxkit cheaper than Mailerr?
For mailboxes alone, yes: 100 cost $300 here and $360 on Mailerr. Mailerr includes warmup and lead validation. With our $3 warmup add-on, Mailerr costs less.
Does Mailerr include warmup?
Yes. Every Mailerr plan includes warmup, with an advanced version on Enterprise. Inboxkit’s warmup is a $3 add-on that runs 14 days on an isolated network.
Does Mailerr have an API or an MCP server?
Its site has no public API documentation and lists no MCP server. Inboxkit includes a REST API with 119 endpoints and a remote MCP server on every account.
How do I move from Mailerr to Inboxkit?
Open a free account, buy or connect domains, and add mailboxes. Export them in one click to your sequencer. Keep Mailerr sending until your campaigns have moved.
Open a free account
$3 a mailbox, no minimum. Google Workspace, Microsoft 365 and Azure.
