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KerioConnect vs ProtonMail comparison

 

Comparison Buyer's Guide

Executive Summary

Review summaries and opinions

We asked business professionals to review the solutions they use. Here are some excerpts of what they said:
 

Categories and Ranking

KerioConnect
Ranking in Email Applications
9th
Average Rating
6.8
Reviews Sentiment
7.3
Number of Reviews
10
Ranking in other categories
Email Archiving (8th)
ProtonMail
Ranking in Email Applications
10th
Average Rating
8.6
Reviews Sentiment
8.0
Number of Reviews
2
Ranking in other categories
No ranking in other categories
 

Mindshare comparison

As of June 2025, in the Email Applications category, the mindshare of KerioConnect is 4.8%, up from 3.9% compared to the previous year. The mindshare of ProtonMail is 5.9%, up from 3.6% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Email Applications
 

Featured Reviews

David Bloomer - PeerSpot reviewer
Lightweight, simple, and robust; easy to maintain and doesn't require a lot of system resources to run
Kerio Connect does as advertised, so there are no real issues with the product itself. It's developed regularly, so there are constant updates. Possibly, the support and development have lessened since they've sold the company, but as far as the product itself is concerned, there isn't anything that I would suggest needs improvement. If I'm being picky, Kerio Connect uses a proprietary, mappy atom for Outlook, and it would be nice if they used a native mappy connection instead, but that's the only additional feature that I would like to see in its next release. If they have native Outlook map integration, that would be great, but other than that, it's got all the functions that I think a mail server should have.
AP
Trust and anonymity play a key role in secure communications
I am uncertain about the two-factor authentication feature. I have had integrations with other Proton services and have used Proton VPN once, though it has limited features. Simple Mail, which was acquired by ProtonMail, has been very useful for me. The pricing is moderate. I have not used any paid services from ProtonMail. It is not very costly, but I have not used any premium services. I am a customer of ProtonMail. I would rate ProtonMail an eight out of ten due to their transparency and the utility of their simple login feature. My job and company name should remain hidden.

Quotes from Members

We asked business professionals to review the solutions they use. Here are some excerpts of what they said:
 

Pros

"The solution is easy to maintain, unlike Exchange. It's easy to create multiple domains and back up and restore if needed. It also has good security features like anti-spam and antivirus."
"We use the solution as a mail server. It connects with Outlook and is used for calendaring and similar tasks."
"We have contacted technical support a handful of times and received some assistance."
"The user interface is good."
"The most valuable features are security and privacy because you installed it on your server, within your company premises, not in the cloud."
"The most valuable features are its ease of use, excellent pricing, and it is platform agnostic."
"KerioConnect has integration with 365. We can use Outlook, which has its client and can be used with Apple devices. It integrates with the App Store and Microsoft Office. It has a smart router. The spam filtering and antivirus are good."
"What I like most about Kerio Connect is that it supports ActiveSync, and that is its most critical feature. The solution is also a nice, simple, robust, and stable mail server."
"The auto encryption of attachments is valuable."
"What I appreciate most about ProtonMail is that they are trusted, which is why I choose them."
 

Cons

"Most of our clients use Outlook and Kerio Connect. Occasionally, Kerio can be a bit slow. They could make it faster to get onto the web interface without so much load time. It's just slow with Outlook, however, for some reason."
"The search and archiving documentation capabilities need to be stronger."
"Having a native Outlook map integration would make Kerio Connect better."
"I would like to see better support from their support team."
"KerioConnect is stable as long as you use a strong password."
"KerioConnect continues to improve with regular updates throughout the year. They must be added to the roadmap, which requires approval."
"You cannot integrate with other services like Google Docs, Google Assistant, Google Calendar, etc."
"We are considering switching to Microsoft Exchange. One reason is that it doesn't improve our workflow and doesn't integrate well with Microsoft 365 applications."
"One improvement could be the integration between ProtonMail and Proton Pass, allowing sharing of specific secrets via email."
"I think it is good but I feel that only tech-savvy people use ProtonMail. It is not that popular among other people."
 

Pricing and Cost Advice

"The solution's pricing depends on how long you plan to keep it because you pay on a per-year basis. You might have a one-time setup cost for something like Microsoft Exchange or a Linux mail server. I'd say this solution is expensive on a per-year basis, almost 2000-3000 dollars annually. It doesn't seem to pay off yet, so we're considering switching to another product."
"KerioConnect has a first-time cost and yearly subscription. It is not expensive."
"The price of Kerio Connect is better when comparing it to others solutions."
"The pricing is about $3 per mailbox per month."
Information not available
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Top Industries

By visitors reading reviews
Computer Software Company
15%
Comms Service Provider
13%
Manufacturing Company
7%
Real Estate/Law Firm
7%
Computer Software Company
15%
Educational Organization
12%
Comms Service Provider
12%
Manufacturing Company
7%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
No data available
 

Questions from the Community

What do you like most about KerioConnect?
The most valuable features are security and privacy because you installed it on your server, within your company premises, not in the cloud.
What is your experience regarding pricing and costs for KerioConnect?
KerioConnect has a first-time cost and yearly subscription. It is not expensive.
What needs improvement with KerioConnect?
KerioConnect continues to improve with regular updates throughout the year. They must be added to the roadmap, which requires approval. In larger organizations, the server's capabilities and the da...
What is your experience regarding pricing and costs for ProtonMail?
The pricing is competitive, offering good value on the average plan. It’s approximately $100 for annual billing.
What needs improvement with ProtonMail?
The UI was previously cumbersome, however, it has improved. One improvement could be the integration between ProtonMail and Proton Pass, allowing sharing of specific secrets via email. However, thi...
What is your primary use case for ProtonMail?
I use ProtonMail for exchanging invoicing with clients, managing financial information, and receiving notifications from bank accounts and investment brokers. It's dedicated to high-importance comm...
 

Comparisons

 

Overview

 

Sample Customers

Southern Tier Brewing Company, Innotta, Baustoff + Metall, Hamifleurs, Chanson TV, Ryman Stationery
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