Benchmark Builder — JavaScript Performance Testing
Free online JavaScript benchmark tool. Compare code snippet performance with operations-per-second metrics and visual bar charts. No sign-up required.
What Is a Benchmark Builder?
A benchmark builder lets you measure and compare the performance of different code approaches. Enter two or more JavaScript code snippets, and the tool runs each one thousands of times to measure operations per second, average execution time, and relative speed. This helps you make data-driven decisions about code optimization.
How to Run Benchmarks
- Enter JavaScript code in each benchmark case.
- Give each case a descriptive name.
- Add more cases with the + Add Case button.
- Click Run Benchmark to measure all cases.
- View results with ops/sec, average time, and a visual comparison bar.
Common Use Cases
- Algorithm Comparison — Compare different implementations of the same algorithm to find the fastest approach.
- String Manipulation — Test whether string concatenation, template literals, or array join is faster for your use case.
- Data Structure Selection — Benchmark Map vs Object, Set vs Array, or different iteration methods.
FAQ
How accurate are the results?
Results use performance.now() with microsecond precision and include warmup runs. However, JavaScript benchmarking in a browser can be affected by garbage collection, JIT compilation, and other factors.
Is the code executed safely?
Code runs in your browser via the Function constructor. Avoid code that accesses sensitive APIs or creates infinite loops.
Can I benchmark async code?
Currently the tool supports synchronous code. For async benchmarks, wrap your code in synchronous patterns or use dedicated tools like Benchmark.js.