🚀 load-sim

load-sim is a lightweight, fast, and customizable CLI tool for API load testing and performance benchmarking. It helps developers simulate high traffic, measure response times, and analyze system performance directly from the terminal.

✨ Features

✔ Concurrent request simulation
✔ Configurable total requests and concurrency
✔ Warm-up request support
✔ Real-time terminal progress bar
✔ Detailed performance metrics
✔ Percentile calculations (P50 / P75 / P90 / P95)
✔ JSON, CSV, and HTML report generation
✔ Custom headers and request body support
✔ Timeout control

📦 Installation

Global install

npm install -g load-sim

Or use with npx

npx load-sim test

🚀 Usage

Basic load test

load-sim test https://example.com

Custom requests and concurrency

load-sim test https://example.com --requests 100 --concurrency 20

Send JSON body with headers

load-sim test https://example.com/api \
  --method POST \
  --body '{"name":"test"}' \
  --headers '{"Content-Type":"application/json"}'

Warm-up run

load-sim test https://example.com --requests 50 --warmup 5

📊 Report Types

Text report (default)

load-sim test https://example.com

JSON report

load-sim test https://example.com --report json

CSV export

load-sim test https://example.com --report csv

HTML report

load-sim test https://example.com --report html

Custom output file

load-sim test https://example.com --report html --output report.html

📈 Sample Output

--- Load Test Report ---
URL: https://example.com
Total requests (measured): 100
Warm-up ignored: 5
Success: 98
Failures: 2
Min: 120 ms
Max: 980 ms
Avg: 344.5 ms
P50: 310 ms
P75: 420 ms
P90: 650 ms
P95: 890 ms
Test duration: 5020 ms (19.92 req/sec)
Status counts: { '200': 98, '500': 2 }

🛠 Tech Stack

Node.js Commander.js Axios p-limit cli-progress

📄 License MIT License

🤝 Contributing Contributions are welcome! Fork the repo, make your changes, and submit a pull request.

💡 Author Usaid GitHub: https://github.com/usaidgithub npm: https://www.npmjs.com/package/load-sim