Configuration

Use YAML configuration files to store and version control your load test parameters.

The YAML Format

Instead of passing dozens of flags to the CLI, you can define your test pattern, settings, and assertions in an overload.config.yaml file.

test_type: load
config:
  target_rps: 100
  ramp_up_seconds: 30
  hold_duration_seconds: 300
  ramp_down_seconds: 15
  concurrency: 50
  timeout_seconds: 30.0
thresholds:
  - metric: p95_latency_ms
    operator: "<"
    value: 500
  - metric: error_rate_pct
    operator: "=="
    value: 0

Generating Configurations

You don't need to write these files by hand. The easiest way to generate a valid config file is to:

  1. Start the browser UI (overload ui).
  2. Configure your test pattern and assertions visually.
  3. Click the Save Config button at the top right of the Test Runner page.
  4. This writes the settings directly to overload.config.yaml in your directory.

Running with Config Files

To use your config file in the CLI (for example, in CI/CD pipelines):

overload run --collection my_api.json --config overload.config.yaml

CLI Overrides

CLI flags take precedence over the values in the config file. This is extremely useful for overriding a specific setting dynamically while keeping the rest of the configuration intact.

# The config file specifies target_rps=100, but we override it to 200 for this run
overload run --collection api.json --config overload.config.yaml --rps 200