
LeetCode
Codility
CodeSignal
iMocha
HackerEarth
Codewars
TestGorilla
HackerRank is a platform that allows companies to conduct interviews remotely to hire developers and for technical assessment purposes.

Slack
Rocket.Chat
Discord
Element.io
Telegram
Zulip
Microsoft Teams
Mattermost is an open source alternative to Slack.

Which is more popular?
Mattermost might be a bit more popular than HackerRank. We know about 75 links to it since March 2021 and only 67 links to HackerRank.
Website, pricing, platforms and company facts side by side.
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| Website | hackerrank.com | mattermost.com |
| Pricing | — | |
| Company | — | Startup from the United States |
| Listed in |
What each product offers, as listed by its team.


Possible disadvantages
Possible disadvantages
An editorial look at what each product does well and who it suits.


Overall verdict
Why this product is good
Recommended for
HackerRank is recommended for students, individual learners, and job seekers looking to improve their coding skills, as well as for companies seeking an efficient way to evaluate candidates' technical abilities during the hiring process.
Overall verdict
Why this product is good
Recommended for
Mattermost is recommended for organizations that prioritize data privacy and security, need extensive customization options, or are looking to integrate a collaboration tool into existing systems. It is also suitable for teams in regulated industries requiring on-premises solutions.
Walkthroughs and reviews on video.
Is HackerRank A Good Idea?
More videos
Mattermost - An Open Source, Self Hosted, Slack Chat Alternative
More videos
How often each product is chosen within a category, 0–100% relative to the other.


Share your experience with using HackerRank and Mattermost. For example, how are they different and which one is better?
External articles and on-site reviews we used to compare the two products.


What are LeetCode and LeetCode alternatives good for?LeetCode💡Interested in leveling up your career? Apply to the Formation Fellowship...
HackerRank’s challenges cover a wide range of topics and difficulty levels, allowing developers to enhance their problem-solving skills and learn new algorithms and data structures. The competitive nature of...
HackerRank offers a wide array of challenges across various domains such as algorithms, mathematics, SQL, and functional programming. Its interface is user-friendly, and the platform provides detailed feedback on...
Mattermost is an open-source platform that enables safe collaboration in self-hosted chat programs featuring file sharing, search, and integrations; groups and businesses can use it as an internal chat.
Mattermost uses monolithic architecture, which is tightly coupled and complex to understand. It restricts the scalability of the collaboration tool, which is a limitation for growing businesses. In that case,...
Below is a curated list of the 12 best self-hosted messaging apps like MirrorFly, Mattermost, Zulio, Nextcloud, and Rocket.chat that offer unique collaboration features and lets you take full control of your data.
Recommendations tracked on public social media and blogs since March 2021.


This way, you transfer what you already know (problem-solving) but only change the syntax. Platforms like Hackerrank are also great to solve the same problem in different languages and learn from other people’s solutions. - Source: dev.to / about 1 year ago
Firstly, solve some common data structure problems with it. Implement some data structures like arrays, linked lists, stacks, queues, etc. You can check common problems on LeetCode, Hackerank or some other resources. - Source: dev.to / over 2 years ago
I don't have a consecutive internet connection and I can't keep up learning process so I started practicing in hackerrank.com I have started some challenges in python and c++ there. Thus I have no internet connection so I cannot practice... Source: almost 3 years ago
The amazing thing is that there is almost always an open-source alternative that is 10x better in many ways, in the case of slack https://mattermost.com/ I'm looking forward for AI to make it very easy to deploy your own tools and walk... - Source: Hacker News / 30 days ago
How does it compare to MatterMost [1]? [1] https://mattermost.com/. - Source: Hacker News / 4 months ago
Slack's value is real, especially for cross-company conversations with clients and vendors. But for internal communication in companies that care about data residency or audit requirements, Mattermost is a credible self-hosted... - Source: dev.to / 5 months ago
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Rocket.Chat is a Web Chat Server, developed in JavaScript, using the Meteor fullstack framework.
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CodeSignal is the leading assessment platform for technical hiring.
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Step up your game with a modern voice & text chat app. Crystal clear voice, multiple server and channel support, mobile apps, and more.
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