Executing YAML-based projects

YAML-based projects, either hybrid with a NeoLoad Controller project file and YAML file(s) or with only YAML file(s), can be executed through different ways via:

NeoLoad Controller command line

Configuring a test with NeoLoad as-code can be carried out with the command line. The -project argument allows declaring the NeoLoad project (".nlp") to launch. For more information, see -project in List of arguments.

-project can be run in command line, then test elements can be declared by specifying the corresponding YAML file(s).

-project can also be used for each file as an alternative to putting all files after -project. For example, both examples below can be used:

-project "<path>/myproject.nlp" "<path>/servers.yaml" "<path>/user_paths.yaml"


-project "<path>/myproject.nlp" -project "<path>/servers.yaml" -project "<path>/user_paths.yaml"

-project can specify a folder that contains the default file "default.yaml" and the potential files referenced by the includes.

Project folder

NeoLoad needs a project folder where resources like JAR dependencies or CSV files for File variables when loading the project can be found.

The project folder is also used to store temporary files and the test result.

The project folder is:

"Run a test" section from NeoLoad Web

The "Run a test" section of NeoLoad Web allows launching a YAML-based project.

  1. Upload the Project.

    The interface allows you to upload manually or through a GIT import:

  2. Set-up your test and launch the test.
    For more information about how to run a test in NeoLoad Web, see Run a test in NeoLoad Web documentation.

NeoLoad Web API

  1. Upload the Project with the endpoint "/ Projects" of the Runtime API.

    The API allows you to upload:

  2. Execute a scenario within the uploaded Project with the endpoint of the Runtime API.

    Specify the YAML file(s) to load. If you do not specify any, then NeoLoad will load "default.yaml" if present.

Use cases and examples

Overriding Scenario settings and Environment for an automated test

In this use case, the user will use a YAML file describing the Scenario to use instead of the existing one in a NeoLoad project.

The YAML file to use for the scenario settings to apply is:

- name: MyScenario
 - name: MyPopulation
     users: 500
     duration: 15m

When having the same name, the scenario included in the YAML file replaces the scenario existing in the NeoLoad project. Also, if the scenario available in the YAML file does not exist in the NeoLoad project, it is then added in the project. In this example, we consider that a "Myscenario" scenario already exists in the NeoLoad project, is then replaced by the scenario of the same name specified in the YAML file.

The same mechanism can be used to override Server host names and Test data:

- name: myapp
  host: myapp-staging.company.com
  scheme: https
  port: 443
- file:
    name: cities_file
    path: staging/data/list_of_cities.csv
    is_first_line_column_names: true
    change_policy: each_iteration
    scope: global

The user can then run the following command line:

NeoLoadCmd.exe -project "<neoload projects path>/MyProject/MyProject.nlp" "<neoload projects path>/myproject-scenarios.yaml" "<neoload projects path>/myproject-environment.yaml"-launch MyScenario

Or create a Zip archive with the content of the <neoload projects path> folder, upload it and run it from NeoLoad Web.

Structuring YAML files per environment

Here is an example of using only YAML files, for two different execution environments:


You should add top-level files that include the required files for each environment:


- common/design.yaml
- staging/servers.yaml
- staging/variables.yaml
- staging/slas.yaml


- common/design.yaml
- preprod/servers.yaml
- preprod/variables.yaml
- preprod/slas.yaml

And a default file for example:


- staging.yaml

Then, zip the whole content and: