There are a lot of inbox providers in the cold email space right now. The problem is that none of them really do everything.
Some have a decent API but terrible support — you're chatting with a bot or waiting two days for an email reply. Others have a great team and good support, but no API, no real app, and you're placing orders through Google Sheets. It's 2026 and you're tracking inboxes in a spreadsheet. That shouldn't be the standard.
We built SimpleInboxes because we got tired of this exact problem. We wanted one provider that had good infrastructure, good pricing, real support, a proper API, and an ordering experience that actually makes sense. Here's how the landscape looks.
What actually matters when picking a provider
Skip the marketing pages. Here's what you should be checking:
- Where are the IPs? US-based IPs for Microsoft consistently outperform offshore ones. A lot of providers sell you IPs from India or Eastern Europe and call them "premium." They're not.
- Are tenants isolated? If your domain sits on a shared admin with other senders, one bad actor tanks your reputation. You want one domain per admin.
- Who does the DNS? SPF, DKIM, DMARC, MX — this needs to be done right. Some providers leave it to you, some half-do it. It should be fully handled.
- What does support look like? Not "we have a help center." Can you talk to a real person who understands cold email, during your business hours?
- How do you actually order? Is there an app with a proper order flow, or are you filling out a form and waiting for a confirmation email?
The providers
SimpleInboxes
- Microsoft 365: $2.99/inbox/mo standard, $2.75 at 100+ inboxes
- Google Workspace: $3.30/inbox/mo standard, $3.00 at 100+
- Infrastructure: Isolated US-based Azure tenants for Microsoft. Google routed through US data centers.
- DNS: Fully done for you — SPF, DKIM, DMARC, MX. Inboxes arrive authenticated.
- Support: Dedicated account manager with direct access in Slack. Real humans, US-based, available during US hours.
- API: Full REST API, available to every customer regardless of plan size.
- Ordering: Dashboard with an integrated order flow — pick your domain, pick your names, pick your sending tool, done. No jumping between tabs.
- Minimums: None. Order 1 inbox or 1,000.
- Delivery: Under 24 hours on average.
The whole order flow is connected. You pick the domain, the inbox names, and the sending tool in one step. Your sending tool credentials can be pre-saved, and there's a checkbox to auto-upload inboxes with your preferred settings. You don't need to click into different views or manage things separately. Customers consistently say the same thing: "it just makes sense."
Mailforge
- Pricing: Around $3.00–$3.50/inbox/mo depending on volume
- Infrastructure: Mixed IP locations
- DNS: Partially automated
- Support: Ticket-based, email support
- Minimums: Varies
Mailforge has a large user base and is well-known in the space. If you want a mainstream option, it works. But the support is ticket-based, and you may not always know where your IPs are located.
Infraforge / InboxKit
- Pricing: Around $3.90/inbox/mo
- Infrastructure: Shared tenants in some cases
- DNS: Manual or semi-automated
- Support: Email tickets
- Minimums: 10 inbox minimum on most plans
Higher pricing with minimum order requirements. The ordering experience tends to be fragmented — you add domains in one section, create orders in another, and manage settings in a third. DNS setup is often partially left to you.
Where providers typically fall short
The pattern we see over and over is providers doing one or two things well and dropping the ball on everything else:
Good API, bad support. Some providers have built solid technical infrastructure, but when something goes wrong, you're talking to a chatbot or waiting for an email reply from someone who doesn't fully understand the problem.
Good support, no tech. Other providers — particularly smaller US-based ones — have responsive teams and know cold email well. But they have no API, no real app, and you're ordering through Google Sheets or a basic form. It's hard to scale when your entire workflow is manual.
Cheap pricing, bad infrastructure. You can find inboxes for less, but they're on shared tenants with offshore IPs. You save a dollar per inbox and lose it in deliverability.
The question isn't "who's the cheapest" — it's "who does the whole thing well?"
Pricing at a glance
| Provider | Microsoft 365 | Google Workspace | Minimum Order | |---|---|---|---| | SimpleInboxes | $2.75–$2.99/mo | $3.00–$3.30/mo | None | | Mailforge | ~$3.00–$3.50/mo | Varies | Varies | | Infraforge | ~$3.90/mo | N/A | 10 inboxes | | InboxKit | ~$3.90/mo | Varies | 10 inboxes |
All SimpleInboxes plans include full API access, a dedicated account manager, done-for-you DNS, and all features. No upsells, no gated tiers. Volume pricing kicks in automatically at 100 inboxes and applies retroactively to your entire account.
For a more detailed breakdown, see our pricing page.
Bottom line
If you're running cold email at any scale — whether it's 10 inboxes for your own sales team or 500 across agency clients — you need infrastructure that doesn't make you choose between good support, good tech, and good pricing.
SimpleInboxes is free to sign up (no credit card required), and inboxes are typically delivered same-day.