Azure DevOps YAML is a configuration file format used to define continuous integration and continuous delivery (CI/CD) pipelines in Microsoft’s Azure DevOps platform. It allows you to define your build, test, and deployment processes as code, which can be versioned along with your source code.

Here’s a basic example of an Azure DevOps YAML pipeline for building and deploying a simple web application:

In this example, the YAML file begins with a trigger section that defines when the pipeline should be triggered (in this case, when changes are pushed to the ‘main’ branch). The pool section specifies the type of virtual machine to be used for the pipeline’s execution.

The steps section contains a list of tasks that will be executed in sequence. Each task can be a built-in task provided by Azure DevOps or a custom script. In this example, the pipeline runs a series of steps including printing a message, installing Node.js, installing project dependencies, building the project, and finally publishing the build artifacts.

You can customize your pipeline further by adding more tasks, integrating with various tools and services, setting up deployment stages, and more. Azure DevOps YAML pipelines offer flexibility and repeatability in defining your CI/CD workflows, and the configurations can be version-controlled along with your source code for easier collaboration and tracking of changes.