Ballast is a tool for snapshot load testing apis.

cargo install ballast

Create a ballast.json config file in your directory.

{
  "endpoints": [
    {
      "name": "GET test",
      "url": "http://localhost:8080/test",
      "method": "GET",
      "concurrent_requests": 5,
      "cycles": 10,
      "threshold": 100,
      "expected_status": 500
    },
    {
      "name": "POST test",
      "url": "http://localhost:8080/test",
      "method": "POST",
      "concurrent_requests": 5,
      "cycles": 10,
      "threshold": 100,
      "expected_status": 200,
      "headers": {
        "Content-Type": "application/json"
      },
      "body": {
        "payload": {}
      }
    }
  ]
}

Note: For more configuration options, see the Configuration section.

ballast # in the directory with ballast.json

What is snapshot testing?

Snapshot testing is a commonly used technique for testing UI frameworks such as Jest + React. It involves capturing a "snapshot" of the DOM at a specific point and using it as a reference for comparison after making changes.

How does this apply to APIs?

Applying a similar approach, when running a load test, ballast automatically generates a snapshot of your test. By comparing performance to a snapshot after making changes, API developers can assess how these changes affect performance.

Configuring Tests

Below are the available configuration options for use in ballast.json for configuring test(s).