What are Secure Alternatives to Slack or WhatsApp That can be Used by a Small Team

Slack has been ruling offices, WhatsApp is incredibly popular for personal chats. And while these apps offer many useful features, some teams, especially those concerned with privacy and data breaches, are looking for secure alternatives to Slack or WhatsApp. 

Work conversations are probably the topmost area where chats and calls require the greatest confidentiality. Work chats often involve sensitive information that companies may not want to share with the public or their competitors. This information could include confidential data, trade secrets, financial information, and personally identifiable information (PII) of employees or customers.

To protect messages and calls from unauthorized access and interception, it’s important to consider secure alternatives to Slack or WhatsApp, that offer the main security components: Full end-to-end encryption, user authentication, secure data storage, secure transmission, two-factor authentication, auto deletion of messages, vulnerability testing and more, can help ensure that user data and communications are protected. 

Slack Privacy Flaws

  • An attacker with access to a compromised machine can easily extract all of a user’s Slack workspaces, chat messages, files, and history.
  • By stealing the session cookies stored on a user’s machine, attackers can gain access to the user’s workspace. Once they have acquired the necessary data, they can launch a virtual machine, install the Slack app, and copy the stolen data to the same location on the virtual machine. By launching Slack, the attacker gains full, live access to the user’s workspaces. Although this activity is recorded in the workspace Access Logs on the server-side, the user may not be aware of it unless the attacker actively attempts to impersonate them in the workspace.
  • Malicious apps can potentially exfiltrate this data without the victim’s knowledge or awareness.
  • By using Slack, businesses must entrust their most confidential data and communication to the platform.

WhatsApp Privacy Flaws

  • If you do not opt out in the settings, WhatsApp shares your messaging metadata with Facebook. When you use the same phone number for both WhatsApp and Facebook, the profiles can be linked with ease.
  • Links to chats on the platform are still accessible, and this has been deemed an intentional product decision. Group admins have the option to invalidate the link if they choose to do so, especially for sensitive groups.
  • Meta/ Facebook is the owner of WhatsApp, which has integrated the messaging service with Messenger and Instagram at the back end. While the move is aimed at facilitating end-to-end encryption for secure communication, some view it as a potential cause for concern. Source


Secure Alternatives to Slack or WhatsApp

There are several alternatives that can be used by small teams. Some options include:

  • Zangi:


Zangi is a secure messaging app that offers a free anonymous messenger and calling app with military grade encryption mechanisms always on by default. Zangi does not collect any data and is serverless, doesn’t store any of it on any servers, eliminating the possibility of any data leaks and breaking into your account. 

Special features: The app also includes premium privacy features including stealth mode, self-destructing messages, passcode lode, wipe passcode, prevent screenshots.

For Businesses: Zangi also has Business solutions for small or large companies who want fully secure and independent communication within a system set up on their own servers.  You’ll have a safe place for all your calls, conferences, messages and collaboration, and the app will be under your own name and branding.

  • Signal: 


Signal is a secure messenger which uses end-to-end encryption to ensure that only the sender and recipient can access messages. Its code is open source, allowing anyone to review it for security vulnerabilities. 

Special features: Additionally, Signal collects minimal user data and does not store message metadata. The app also includes advanced security features such as identity verification, disappearing messages, and a PIN to protect user accounts. 

  • Wire: 


Wire is a secure messaging and collaboration platform that offers end-to-end encryption, group messaging, voice and video calls, and file sharing. Wire uses end-to-end encryption to protect messages and calls, and is open source. 

Special features:  It also offers additional security features such as self-destructing messages and timed messages, anonymous sign-up, two-factor authentication, and the ability to delete messages for both the sender and receiver.

  • Element


Element (formerly Riot.im) is an open-source, end-to-end encrypted messaging app that supports group messaging, voice and video calls, and file sharing. It uses the Matrix open standard for messaging, which ensures that the data is decentralized and not stored on a central server. 

Special features: Cross-platform support including Windows, Mac, Linux, iOS, and Android, It also offers integrations with other collaboration tools such as Jira and GitHub. Allows users to customize the platform to suit their preferences.


These secure alternatives to Slack or WhatsApp offer various features and security measures, so it’s important to evaluate which one is the best fit for your team’s specific needs and preferences.

Key Takeaways

  • Instead of having to adapt your business to WhatsApp or WhatsApp for Business and its interface, Zangi for Business tailors its solutions and branding to fit your business needs.
  • With Slack, businesses must entrust their most confidential data and communication to the platform. On the other hand, Zangi for Business puts your privacy and security in your control, ensuring that nobody else can access your data.