Mattermost versus Slack

Feature Slack Plus Mattermost Enterprise Edition
ENTERPRISE MESSAGING
Unlimited messaging, file sharing and search Yes Yes
Corporate directory integration through ADFS, Okta, SAML and LDAP Only Okta Yes
Scales to thousands of users Yes Yes
Native iPhone, iPad and Android apps Yes Yes
Native Windows and Mac apps Yes Yes
SECURITY
Support for 256-bit SSL encryption for data in transit Yes Yes
Multi-factor authentication for enhanced security Yes Yes
Support for encryption at rest Unknown Yes
Run on-premises with existing security infrastructure Yes
Ability to run without access to public internet Yes
Mobile apps can deploy to on-premises Enterprise App Store Yes
Source code available for review by customer security teams Yes
Ability to run as single-tenant system, without risk of service or security failures caused by other tenants Yes
COMPLIANCE
Permanent continuous archive for messages and channels, including edits and deletes Yes Yes
Complete access to logs of all server records, including configuration changes, user activity, logins and IP addresses Yes
Choose database compatible with customer’s compliance, backup and disaster recovery policies Yes
Compliance reporting with oversight protection Yes
Data sovereignty – Ability to control the country in which your data is stored and the laws under which it may be legally accessed. Yes
Ability for your organization to control the key used for encryption-at-rest Yes
Ability to verify data deletion Yes
Ability to verify access restrictions to confidential data have been enforced Yes
Ability to verify access to disaster recovery solution Yes
CUSTOMIZATION AND INTEGRATION
Deploys on your own domain Yes Yes
Compatible with webhook integrations for Slack Yes Yes
Compatible with slash command integrations for Slack Yes Yes
Integrations with wide array of systems, including Jira, Jenkins/Hudson, Redmine, Trac, GitLab, GitHub and more Closed source with limited customization Open source and highly customizable
Custom themes with 20 different color setting options, plus pre-defined color themes Yes
DEVELOPER SUPPORT
Basic APIs Yes Yes
Complete access to all server APIs Yes
Offers language-specific API drivers for building custom integrations Yes
Ability to self-compile and customize native applications on desktop and mobile Yes
DEPLOYMENT
Pre-packaged Amazon Machine Instance (AMI) Yes
On-premise virtual appliance deployment Yes
On-premise deployment as single Linux binary on Ubuntu, Debian, RHEL, Oracle Linux, and SLES Yes
Use your own database compliant with internal IT policies Yes, MySQL and Postgres
LOCALIZATION SUPPORT
Multi-language support Yes, English, German, French, Spanish, Portuguese, Dutch, Russian, Chinese, Korean, Japanese
Localization support with the ability for customers to self-localize and customize user interface text Yes
CUSTOMER SUPPORT
Premiere Support Available Yes Yes
Public Feature Request Forum Yes
Public Issue tracker Yes
Release schedule Unknown – Marketing announcements but no release notes Bi-monthly – Mattermost releases new improvements on the 16th of every other month
Help and product documentation Authored by Slack Technologies, Inc. Authored by Mattermost, Inc. with the ability to accept contributions from users and customers
Ability to sponsor new features to be added to core product Yes
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