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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
7.2
Reviews Sentiment
7.3
Number of Reviews
11
Ranking in other categories
Email Archiving (7th)
ProtonMail
Ranking in Email Applications
7th
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 2026, in the Email Applications category, the mindshare of KerioConnect is 3.8%, down from 4.7% compared to the previous year. The mindshare of ProtonMail is 6.8%, up from 5.9% compared to the previous year. It is calculated based on PeerSpot user engagement data.
Email Applications Mindshare Distribution
ProductMindshare (%)
ProtonMail6.8%
KerioConnect3.8%
Other89.4%
Email Applications
 

Featured Reviews

MM
Senior Systems Tech/Admin at Samco Software Inc.
A seamless setup ensures smooth communication with comprehensive support
We remain a partner with Sophos and use XG S Firewalls without AWS implementation. We only use Sophos endpoint and Sophos Central. We host some clients on-premise while others we host remotely. The VPN connection is easy and proprietary, so it's not open to any other VPN clients. Communication with other mail servers is seamless. It can communicate with Gmail and Outlook without issues, provided the DNS settings are correct. We monitor our servers and security logs, implementing GeoIP blocking. We frequently block China and India IPs due to brute force attacks on our servers. We have extensive experience with KerioConnect. Backing up and maintaining it is straightforward compared to Microsoft Exchange, making it administrator-friendly. On a scale of 1-10, this solution rates an 8.
AP
Media Content Creator Intern
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 most valuable features are security and privacy because you installed it on your server, within your company premises, not in the cloud."
"This solution is our SMB alternative to Exchange, installed for more than forty SMB customers in a Linux environment with all of the collaboration features."
"The most valuable features are its ease of use, excellent pricing, and it is platform agnostic."
"We use the solution as a mail server. It connects with Outlook and is used for calendaring and similar tasks."
"The user interface is good."
"It's relatively simple to use."
"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."
"ProtonMail is cost-effective for encrypted mailing, offering extensive features and customization, especially if you want to provide your own hashing and keys."
"What I appreciate most about ProtonMail is that they are trusted, which is why I choose them."
"The auto encryption of attachments is valuable."
 

Cons

"I would like to see better support from their support team."
"The search and archiving documentation capabilities need to be stronger."
"KerioConnect is stable as long as you use a strong password."
"Most of our clients use Outlook and Kerio Connect. Occasionally, Kerio can be a bit slow."
"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."
"I don't particularly like this solution. I would not recommend this solution to others."
"We cannot compete with them because they're fully integrated with their applications."
"You cannot integrate with other services like Google Docs, Google Assistant, Google Calendar, etc."
"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

"KerioConnect has a first-time cost and yearly subscription. It is not expensive."
"The pricing is about $3 per mailbox per month."
"The price of Kerio Connect is better when comparing it to others solutions."
"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."
Information not available
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Top Industries

By visitors reading reviews
Comms Service Provider
13%
Manufacturing Company
10%
Construction Company
9%
Computer Software Company
7%
Comms Service Provider
22%
Educational Organization
7%
Construction Company
6%
Computer Software Company
6%
 

Company Size

By reviewers
Large Enterprise
Midsize Enterprise
Small Business
By reviewers
Company SizeCount
Small Business10
Midsize Enterprise2
No data available
 

Questions from the Community

What is your experience regarding pricing and costs for KerioConnect?
The pricing is very easy to understand. As a partner, we have a monitoring system that informs us when subscriptions expire, allowing us to handle renewals. The pricing is very competitive.
What needs improvement with KerioConnect?
Since KerioConnect is a setup and go solution, everything works on its own. The only administrative tasks required are keeping it up to date, monitoring security logs, and ensuring protection from ...
What is your primary use case for KerioConnect?
Small medium-sized businesses are our primary focus, particularly in warehouse distribution and retail sectors. We are a reseller and purchase directly from Sophos.
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?
In terms of what can be improved in ProtonMail, I think it is good but I feel that only tech-savvy people use ProtonMail. It is not that popular among other people. Therefore, we do not use it for ...
What is your primary use case for ProtonMail?
My use cases include using ProtonMail for Drive occasionally for storing files. After some time, I stopped using that feature. Primarily, I use it for sending emails when I want to maintain anonymi...
 

Comparisons

 

Overview

 

Sample Customers

Southern Tier Brewing Company, Innotta, Baustoff + Metall, Hamifleurs, Chanson TV, Ryman Stationery
Wall street journal,The New york times, The Gurdian, Forbes, Fox News
Find out what your peers are saying about KerioConnect vs. ProtonMail and other solutions. Updated: June 2026.
900,644 professionals have used our research since 2012.