5 Microsoft 365 Inbox ProvidersYou Must Check
Buying Microsoft 365 for cold outreach shouldn’t feel like dealing with enterprise IT.
You’re not here for red tape, “book a demo” forms, or overpriced contracts.
You just want:
- ✅ Fast mailbox setup
- ✅ Clean deliverability
- ✅ DNS + warmup handled
But most Microsoft 365 resellers?
They’re built for internal IT, not for cold email, SDR teams, or growth agencies.
So I did the work.
In this guide, you’ll get:
- 5 Microsoft 365 inbox providers built for cold outreach
- How they handle setup, warmup, and scale
- Which one is best for you(and who should skip)
Miss this, and you’ll waste hours on duct-taped setups… or worse, land in spam.
Let’s dive in.
TL;DR - 5 Microsoft 365 Inbox Providers You Must Check
- Primeforge – Best all-in-one outreach infrastructure
- Maildoso – Best for bulk mailbox setup & reply handling
- Icemail.ai – Best for user-friendly setup & real-time monitoring
- Zapmail – Best for bulk provisioning at scale
- Inframail – Best for unlimited inboxes at flat pricing
Are These Resellers Official?
Yes.
All 5 providers use valid Microsoft 365 licenses. Some are CSPs, others resell via verified partners. We’ve excluded gray-market sellers or shared inbox hacks.
Why It’s Better To Buy From Microsoft 365 Inbox Providers
When you're buying Microsoft 365 for your team, where you buy it from really matters.
Here’s why going with an authorized reseller is the smarter move:
- ✅ You get real Microsoft licenses: No risk of fake or blacklisted accounts. Everything is legal, clean, and safe.
- ✅ You avoid setup headaches: Authorized providers can help you with things like inbox creation, domain setup, and DNS settings, the stuff that takes hours if you’re doing it alone.
- ✅ Better deliverability: With proper warm-up tools and DNS records (like SPF, DKIM, and DMARC), your emails are less likely to land in spam.
- ✅ Support when things go wrong: If an inbox gets flagged or something breaks, you have a real team to call, not a sketchy vendor with no contact info.
- ✅ Built for scale: These resellers (like Primeforge or Maildoso) are made for growth teams. You can spin up dozens or even hundreds of inboxes without juggling different tools.
Buying directly from Microsoft works, but it’s not built for outreach. These resellers are.
5 Microsoft 365 Inbox Providers You Must Check: Quick Comparison
1. Primeforge – Best All-in-One Microsoft 365 Inbox Provider
Primeforge is a modern Microsoft 365 inbox provider built for sales, SDRs, and outreach teams.
Unlike traditional providers that focus on big enterprise IT, Primeforge gives you fast, ready-to-use mailboxes with features tailored for cold email and deliverability.
Here’s why outreach teams love Primeforge:
- It offers full domain and mailbox ownership, no shared accounts or hidden risks.
- You get automatic setup of profile pictures, SPF, DKIM, and DMARC.
- Mailboxes are ready to go in just 30 minutes, not 24+ hours like with standard providers.
- It supports both Google Workspace and Microsoft 365, with bulk pricing and savings.
According to the pricing comparison, Primeforge saves you up to 46% vs Google Workspace and 25% vs Microsoft 365 directly.
Primeforge Pricing
- You’re charged per mailbox slot, not per inbox, so you can reuse slots as needed.
- Pricing starts at $17/month per mailbox (billed yearly) or $20/month (billed quarterly).
- Each domain costs $70/year, billed once (based on .com domains).
- You need a minimum of 10 mailbox slots to start.
- There's a pricing calculator on their site to help estimate based on your outreach volume (emails per sequence and contacts/month).
📌 Example: If you want to send 2 emails per contact to 1,000 contacts/month, Primeforge suggests 5 mailboxes and 5 domains.
Pros & Cons of Primeforge
Our Verdict
Primeforge is the best choice if you're looking for Microsoft 365 inboxes that are easy to set up, warmup-ready, and built for outreach from day one.
You get full control, fast delivery, and pricing that scales.
👉 Next, let’s look at Maildoso, a smart choice for bulk inbox setup and reply handling.
2. Maildoso – Best for Bulk Mailbox Setup & Reply Handling
Maildoso helps you set up a large number of Microsoft 365 inboxes quickly.
It’s made for sales and marketing teams who send lots of cold emails and need an easy way to manage replies, domains, and inbox performance.
What makes it stand out:
- You can set up hundreds of inboxes and domains in just a few minutes.
- It takes care of all the technical stuff, like SPF, DKIM, and DMARC, so your emails land in inboxes, not spam.
- It uses IP rotation, which spreads your sending across different IPs to keep deliverability high.
- You get a Master Inbox, which collects replies from all mailboxes in one place.
- It even tells you if your emails are going to the inbox or spam.
Maildoso Pricing
- Pricing starts at about $3.1 per mailbox.
- You get free domains, and you own them permanently.
- Setup time is super fast, around 10 minutes for 250+ domains and 1,000 inboxes.
- Compared to Google Workspace (which can cost over $3,800 for 400 inboxes), Maildoso only costs about $733 for the same.
That’s a huge saving if you’re sending emails at scale.
Pros & Cons of Maildoso
Our Verdict
If you’re running cold outreach at scale and want to avoid manual setup, Maildoso is a great fit. It’s affordable, fast, and makes managing inboxes and replies much easier.
Up next, let’s take a look at Icemail.ai, the best pick for teams who want clean dashboards and a simple setup.
3. Icemail.ai – Best for Easy Setup & Real-Time Email Tracking
Icemail.ai is perfect if you want to set up Microsoft 365 mailboxes fast and keep track of how your emails are doing.
It’s built for teams that send cold emails and need tools to help improve deliverability without doing all the technical work themselves.
Here’s why it’s a smart choice:
- You can create mailboxes quickly and get started in minutes.
- It automatically sets up email safety records (SPF, DKIM, and DMARC) to keep you out of spam.
- You can see in real time if your emails land in the inbox or go to spam.
- You can connect your own domain or buy one through the platform.
- You only pay for what you use, no contracts or subscriptions.
Icemail.ai Pricing
- Microsoft 365 inboxes cost $3 per mailbox per month.
- If you want inboxes that are already warmed up, it’s $5 per mailbox.
- Domains can be connected or bought through the app, and setup is done for you.
- No subscriptions or long-term plans, it’s pay-as-you-go.
Pros & Cons of Icemail
Our Verdict
Icemail.ai is a great pick if you want a clean dashboard, simple setup, and tools to help you send better cold emails with Microsoft 365.
It’s easy to use, even if you’re not super technical.
Now let’s check out Zapmail, a great option for teams that need to set up a lot of inboxes without slowing down.
4. Zapmail – Best for Bulk Inbox Setup at Scale
If your team sends a lot of cold emails and needs to create dozens or even hundreds of Microsoft 365 inboxes quickly, Zapmail is a great fit.
It’s made for speed, bulk setup, and easy connection to outreach tools like Instantly and Smartlead.
Why teams choose Zapmail:
- You can create lots of inboxes fast, without any tech headaches.
- It sets up your domain’s SPF, DKIM, and DMARC automatically, so your emails don’t go to spam.
- It works with both Google Workspace and Microsoft 365.
- You can connect your own domain or buy one inside the platform.
- It’s made for cold outreach, not general business email.
Zapmail Pricing
- The Starter Plan is $39/month for 10 inboxes.
- The Growth Plan is $99/month for 30 inboxes.
- The Pro Plan is $299/month for 100 inboxes.
- Extra inboxes cost around $3 to $3.50 each, depending on your plan.
- Domains are billed separately, starting from $13 per year.
There’s no long contract; you can pay monthly as you grow.
Pros & Cons of Zapmail
Our Verdict
Zapmail is best for teams that need to launch outreach mailboxes in bulk, fast, and at a fair price.
If you’re running cold email at scale, it gives you what you need without slowing you down.
👉 Coming up next is Inframail, a great choice if you want unlimited inboxes at a flat price.
5. Inframail – Best Choice If You Want Unlimited Microsoft 365 Inboxes
Inframail is for teams that want to send cold emails using Microsoft 365, but don’t want to worry about limits.
Instead of paying for each inbox, you pay one fixed price and get to create as many inboxes as you need.
It’s a good option for big teams or agencies that need lots of sending power. Inframail also makes it easier by setting up everything for you.
Here’s what it helps you with:
- You can make unlimited inboxes every month with no extra charges.
- It helps your emails avoid spam by setting up DNS records like SPF, DKIM, and DMARC for you.
- It includes dedicated IPs to keep your sending safe and trusted.
- You can use your own domain or buy a new one inside the platform.
- You get basic tools to check how your emails are doing and if anything needs fixing.
Inframail Pricing
- $99/month plan: Unlimited inboxes, 1 IP, up to 5 new domains daily.
- $249/month plan: Unlimited inboxes, 3 IPs, and 15 domains daily.
- Domains are extra: start at around $16.44 each.
- Using your own domain? You’ll pay a $5 setup fee.
There are no usage limits on inboxes, great for teams who send at scale.
Pros and Cons of Inframail
Our Verdict
Inframail is a strong pick if you’re sending a high volume of emails and don’t want to deal with mailbox limits or surprise pricing.
It gives you the freedom to grow without worrying about costs going up.
👉 That wraps up the list. Wondering how I chose these five tools?
Let me walk you through what really mattered in the selection process.
How We Evaluated These Microsoft 365 Inbox Providers
When picking the best Microsoft 365 inbox providers for cold outreach, we didn’t just look at big brand names.
We focused on what actually matters to you, whether you’re a sales leader, agency owner, IT manager, or a solo founder running campaigns.
Here’s how we chose these 5 tools:
- We checked if they’re authorized to resell Microsoft 365 (no grey-market hacks).
- They had to offer fast inbox setup, with no waiting days to launch a campaign.
- Tools must handle SPF, DKIM, and DMARC setup for better deliverability.
- We looked for transparent pricing, no hidden costs, or surprise add-ons.
- All tools are made for cold outreach, not just general email hosting.
- We reviewed real user feedback from Reddit, G2, and email communities.
- We gave priority to tools that scale well for small teams and large agencies.
The goal was simple: Only recommend resellers that help you launch and manage inboxes fast, stay out of spam, and grow your outreach without hitting limits.
👉 Up next: A quick guide to help you pick the right tool based on your needs.
Which Microsoft 365 Inbox Provider Fits Your Team Best?
You’re not just buying inboxes, you’re building the core of your outreach system.
The “best” tool depends on how many emails you send, how much control you want, and whether you're working solo or managing a team.
Here’s a quick breakdown based on what you’re trying to get done:
👉 Just match your priority to the right tool, and you’re good to go.
Final Verdict
Most regular Microsoft providers are built for office work, not cold outreach.
That’s why they don’t offer what growth teams actually need: fast setup, inbox control, and email deliverability support.
The 5 resellers in this guide, like Primeforge, Maildoso, and Inframail, are made for a different kind of team.
If you're sending emails every day, running campaigns, or scaling your outreach, these tools are a much better fit.
Here’s the quick take:
- ✅ Go with Primeforge if you want an all-in-one setup with full control
- ✅ Choose Maildoso if reply tracking and domain scale matter most
- ✅ Pick Icemail.ai if you want an easy dashboard and clean setup
- ✅ Try Zapmail if you're setting up lots of inboxes fast
- ✅ Use Inframail if you want unlimited inboxes at a steady price
You don’t need to waste time on IT-heavy resellers. Pick the one that fits your workflow, and start sending.
👉 If you want an outreach setup that just works, with everything ready to go, start with Primeforge.
It’s built for scale, built for deliverability, and built for teams like yours.