Corporate Messenger from Scratch: How We Built a Secure Slack Alternative in 6 Months

Serhii Shypylov

• 2 min read

Introduction

When we started a large IT project, the team grew to 100+ people. Communication needs exceeded the capabilities of standard messengers. We faced data leaks, lack of integrations, and chaos in channels.

A secure corporate messenger is not just a chat; it's the infrastructure backbone of a modern IT team. It must be fast, closed, and flexible.

We decided not to adapt ready-made solutions but to create our own. Here is our journey from idea to launch.

Step 1: Architecture and Technology Stack Selection

The foundation of any messenger is instant messaging. Therefore, the first question is: how to ensure speed and stability?

  • ✅ WebSocket (Socket.io) — for real-time bidirectional communication. Alternatives (long-polling) simply did not provide the required performance.
  • ✅ Node.js + Express — for the backend. Asynchronous nature and a large community were key arguments.
  • ✅ React — for the frontend. The component-based approach is ideal for a dynamic chat interface.
  • ✅ PostgreSQL — for data storage. Reliability and support for complex queries were critical.
The stack is the foundation. Choose technologies not only for their popularity but also for their ability to solve your specific security and scalability tasks.

Step 2: Security as Priority #1

A corporate chat is a treasury of confidential information. Data protection starts with architecture.

  • 🔒 End-to-End Encryption (E2EE) — we used the Signal Protocol algorithm. Encryption keys are generated on users' devices.
  • 🔒 Authentication and Authorization — JWT tokens with a short lifespan and OAuth 2.0 for integration with the corporate portal.
  • 🔒 Server-Level Protection — all data in the database is also encrypted (AES-256). Regular security audits and pentests became routine.

This is not just a 'checkbox'. It's the team's trust and protection of the business from the leakage of strategic plans.

Step 3: Integration into Business Processes

A messenger should not be an isolated island. Its strength lies in connections with other systems.

  • 🤖 CI/CD Bots — notifications about builds, deployments, and errors in Jenkins/GitLab CI directly into DevOps chat rooms.
  • 🤖 Integration with Jira/Trello — creating and updating tasks via special commands in the chat.
  • 🤖 Channels for HR and Onboarding — automatic addition of new employees to relevant chats, distribution of important information.
Integrations transform a chat into a team hub. It becomes a single pane of glass where work happens.

Step 4: Testing, Launch, and Support

Launching such a product is not a finish line, but the start of a new phase. We divided it into stages.

  • 🧪 Closed Beta Testing — 20 developers used the system for 2 weeks, finding critical bugs in encryption.
  • 🚀 Phased Rollout — first the development department, then the entire technical team, and only after a month — the whole company.
  • 🛠 Feedback Loop — a built-in button for complaints and suggestions right in the interface. This gave us hundreds of ideas for improvement.

For the first month after the full launch, we operated in a 'rapid response' mode to eliminate all points of friction.

Conclusion: What Did We Gain?

Building your own messenger is an ambitious but justified task for large IT projects. It's not just a matter of security, but also of flexibility.

We gained a tool perfectly tailored to our processes. We reduced information leaks, automated routine tasks, and united the team in a single digital space.

The key to success is to start not with code, but with a deep analysis of the team's needs. Security, speed, integrations — in that exact order.

Today, our messenger is a living organism that continues to evolve alongside our project.

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Want to implement this in your business? Contact us!

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