Introduction

Building real-time applications at scale presents unique challenges, especially when dealing with persistent WebSocket connections. In this article, I'll share lessons learned from building a WebSocket service that handles over 100,000 concurrent connections.

Architecture Overview

Our architecture consists of several key components:

• Load balancer with WebSocket support
• Cluster of Node.js WebSocket servers
• Redis for pub/sub and shared state
• Monitoring and metrics collection

Performance Optimization

We implemented several optimizations to handle the load:

1. Connection pooling and reuse
2. Binary protocol for message serialization
3. Efficient memory management
4. Horizontal scaling strategies

Lessons Learned

The most important lesson was that WebSocket servers behave very differently under load compared to traditional HTTP servers. Memory management becomes critical, and connection state handling must be carefully designed.

The Beginning

Two years ago, I started working on a SaaS product in my spare time while holding down a full-time job. Today, that product generates over $10,000 in monthly recurring revenue (MRR). Here's how I did it.

Finding the Right Idea

The key was solving a real pain point I experienced myself as a developer. I built APIToolkit because I was frustrated with existing API monitoring solutions that were either too expensive or didn't provide the features I needed.

Building the MVP

I focused on building the smallest possible version that delivered real value. My MVP had just three core features but solved the main pain point effectively.

Growth Strategies

Content marketing and word-of-mouth were our most effective growth channels. By creating valuable technical content and focusing on customer satisfaction, we grew organically without spending on ads.

The Challenge of Distributed Systems

Microservices architectures introduce new failure modes that must be carefully considered during design. In this article, I'll share patterns for building resilient microservices.

Key Patterns

Several patterns have proven particularly valuable:

• Circuit breakers
• Bulkheads
• Retries with exponential backoff
• Dead letter queues
• Graceful degradation

Implementation Examples

Let's look at how to implement these patterns in practice:

1. Using Hystrix for circuit breaking
2. Implementing retry logic in service clients
3. Designing fallback mechanisms

Monitoring and Observability

Resilient systems require excellent observability. We'll cover metrics collection, distributed tracing, and alerting strategies to maintain system health.

Development Environment

After years of experimentation, I've settled on a development setup that maximizes my productivity:

• VS Code with carefully selected extensions
• iTerm2 with Zsh and custom prompts
• Docker for local development environments
• GitHub for version control

Daily Workflow

My typical workday follows this pattern:

1. Morning review of tasks and priorities
2. Focused coding sessions (Pomodoro technique)
3. Afternoon for meetings and communication
4. Evening for learning and experimentation

Productivity Tips

The most important productivity hack is single-tasking. By focusing completely on one task at a time, I achieve better results in less time. Other key practices include time blocking, regular breaks, and maintaining a clean workspace.

Development Environment

After years of experimentation, I've settled on a development setup that maximizes my productivity:

• VS Code with carefully selected extensions
• iTerm2 with Zsh and custom prompts
• Docker for local development environments
• GitHub for version control

Daily Workflow

My typical workday follows this pattern:

1. Morning review of tasks and priorities
2. Focused coding sessions (Pomodoro technique)
3. Afternoon for meetings and communication
4. Evening for learning and experimentation

Productivity Tips

The most important productivity hack is single-tasking. By focusing completely on one task at a time, I achieve better results in less time. Other key practices include time blocking, regular breaks, and maintaining a clean workspace.