PuzzleInbox
Alternative & Review

PuzzleInbox is a cold email infrastructure provider focused on Google Workspace and Microsoft Office 365 mailboxes. Its official homepage describes standard and warmed mailboxes that are delivered in 24-72 hours, DNS-ready, and designed for outbound teams that do not want to manually configure SPF, DKIM, DMARC, OAuth, SMTP/IMAP connections, and warmup workflows.

The product is best understood as a mailbox procurement and setup layer for agencies and sales teams that need many mailboxes quickly. PuzzleInbox states that it is used by 1,200+ agencies and sales teams, has deployed 70,800+ active mailboxes, and is rated 4.7/5 by clients on its own website. These are official website claims rather than independent review-platform metrics.

Public company background is limited. The checked `/about` page returned a 404 page, and the official website did not disclose a founder, launch date, headquarters, or legal entity in the accessible pages reviewed. While this might not directly affect the product's performance rating, it is nonetheless a major red flag. Read the Terms of Service twice and check the reviews thoroughly before risking your money.

Trustpilot: 4.5/5 (34 reviews)
G2: No reviews found

• "been using puzzleinbox for 3 months now. deliverability is solid, mostly hitting primary after warmup. around 85% inbox placement on my campaigns. pricing is cheap like 3-4 bucks per google workspace inbox monthly. way less hassle than rolling your own domains."
• "I use them for my agency. One of the providers I use for warmed inboxes. They started offering office 365 too."
• "they are great i use them!"

Anyone here actually using PuzzleInbox?

🟢 Low Outlook 365 entry price. PuzzleInbox lists Standard Outlook 365 at $0.35 and warmed Outlook 365 at $0.50, which can be attractive for teams that need inexpensive Microsoft-based mailbox volume.
🟢 Google Workspace and Outlook coverage. The platform offers both Google Workspace and Microsoft Office 365 mailboxes, which gives buyers more flexibility than providers that only cover one ecosystem.
🟢 Warmed mailbox option. PuzzleInbox sells warmed Google Workspace and Outlook mailboxes, which may reduce the manual ramp-up burden for teams that do not want to manage early warmup entirely by themselves.

🔴 API access is not clearly disclosed. The official pages reviewed did not show public API documentation or a clear API access policy, which can limit automation for agencies managing many clients.
🔴 Company transparency is thin. The checked About page returned 404, and public pages did not disclose founders, launch date, legal entity, or headquarters.
🔴 Outlook limits are conservative. The Outlook 365 plans state 3 emails per mailbox per day, which may require many mailboxes for campaigns with meaningful daily send volume.

Maildoso is a cold outreach infrastructure provider – we offer domains, SMTP mailboxes, and Google Workspace accounts. The company was founded in August 2023 in Granite Bay, California, by Nikita Bykadarov (Nikita Maildoso).

While other providers offer shared or dedicated IPs, we have developed IP rotation. This means your emails are sent from hundreds of different IPs (making it harder for spam filters to detect a sending pattern), and whenever any IP gets blacklisted, we automatically swap it out for a clean one.

We have also implemented self-healing mailbox technology, which both restores burned-out mailboxes and protects your active email accounts.

The result?
As of May 2026, the spam rate across our entire network of mailboxes is around 5%.

G2: 4.7/5 (181 reviews)

"Tried it mainly because of the good price, but ended up sticking with it since deliverability’s been pretty stable so far" – Thinking about trying "Maildoso". Has anyone here used it? Is it actually better than other tools?

"I tested a small batch first and results were comparable to our Google setup. Ended up moving more campaigns there because of the lower cost. That's a good strategy, buy small package and compare with your current setup" – I want to try Maildoso. What do you guys think about it?

🟢 Dynamic IP Rotation: We rotate your IP addresses in real-time – if an IP gets flagged or blacklisted, we instantly swap it for a clean one before your campaign takes a hit, ensuring your emails consistently land in the primary inbox rather than getting stuck in spam.
🟢 Self-Healing Rotation: An automated resting period for mailboxes every two weeks that clears provider flags and recovers reputation on autopilot.
🟢 Global Customer Domain Tracking: Proprietary technology that allows you to safely include links without compromising your sender reputation.
🟢 Automated Inbox Placement Tests: Free email deliverability infrastructure testing every three days for all mailboxes, giving you real-time visibility into your health.

🔴 Conservative Limits: We suggest sticking to 15 emails a day per box to keep your domains healthy for the long run.
🔴 Google/SMTP Focus: We do not support Microsoft 365/Outlook/Azure environments at this time.
🔴 Lack of built-in warmup. We do not have an integrated warm-up yet, but we are currently working on it.

It’s tempting to choose a provider based solely on the lowest price, but budget infrastructure often leads to hidden costs. When deliverability drops, the consequences usually show up in three areas:

• Burned Leads: High-quality B2B data is expensive. If emails land in spam, those contacts never see the pitch, and the budget spent on data is lost.
• Damaged Domains: Fixing a domain flagged by spam filters can be a massive headache. Often, it’s easier to just buy a new one and start the warm-up process all over again.
• Missed Revenue: Every missed inbox is a missed meeting. In B2B sales, losing even one connection can mean missing out on thousands in closed revenue.

Cold email infrastructure is better viewed as an investment. Maildoso provides the technical tools to protect domain reputation and help keep emails in the primary inbox.

Pre-warmed mailboxes sound great in theory. However, since they aren't always warmed up properly—and you have no way to verify this, forcing you to simply take the provider's word for it – while also being more expensive, we recommend warming them up yourself using any sequencer or third-party service. This way, you can be 100% certain that your mailboxes are actually ready for use.

You can do this through Maildoso. There are no conclusive studies on the market proving that Google Workspace mailboxes perform better than SMTP (and in any case, we offer both types).

It’s also important to note that their order delivery time (according to the PuzzleInbox website) ranges from 24 to 72 hours. For many teams, this is simply too long – at Maildoso, we create SMTP mailboxes in seconds, and Google Workspace accounts in just a couple of hours.