loadtest is a Node.js-based load testing tool that simulates realistic server traffic patterns. Unlike traditional tools, it lets you control both concurrency levels and exact request rates per second, revealing how your server performs under sustained load rather than just burst traffic.

Key capabilities include:

Test HTTP, HTTPS, and WebSocket endpoints with customizable request patterns
Set precise request rates (rps) independent of concurrency for realistic load simulation
Configure requests with custom headers, cookies, POST/PATCH bodies, and content types
Collect detailed performance metrics: mean response times, percentiles, and throughput
Keep-alive connection support for testing persistent connections
Programmatic API for integrating load tests into your deployment pipeline

Why choose loadtest: It provides Apache ab compatibility while offering superior flexibility. You can simulate real-world conditions by maintaining constant request rates—revealing performance degradation that burst-based testing misses. The tool scales across multiple CPU cores and integrates seamlessly into CI/CD workflows, making it ideal for pre-deployment validation where you can enforce performance thresholds (e.g., 99th percentile response time limits).

Installation is straightforward via npm, with support for Node.js v16 and later. The tool saturates approximately 5,000-7,000 requests per second per CPU core, making it suitable for testing most web applications without requiring external load generation infrastructure.