In what format are Azure Resource Manager templates written?

Azure Resource Manager (ARM) templates are written in JSON (JavaScript Object Notation) format. This format is widely used for representing structured data, making it a suitable choice for defining infrastructure as code within Azure. JSON's human-readable text format facilitates easy editing, while its structured syntax allows for the definition of complex resources and their relationships in a clear manner.

Using JSON, you can specify the resources you want to deploy, their properties, and the configurations necessary for Azure to understand how to set them up. This enables automation and reproducibility when deploying Azure resources, which is essential for efficient cloud management.

In addition to JSON, other formats like XML and YAML can be used in various contexts, but they are not the standard for Azure Resource Manager templates. HTML is not applicable as it is a markup language designed for structuring content on the web rather than defining configuration or deployment templates for cloud resources.