ARM Template Structure and Syntax

ARM templates are JSON files that define Azure resources declaratively. In this lesson, you will learn the anatomy of an ARM template, understand each section, and write your first complete template.

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Template Skeleton

Every ARM template has the following top-level structure:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {},
  "variables": {},
  "functions": [],
  "resources": [],
  "outputs": {}
}

Section	Required	Description
$schema	Yes	URL of the JSON schema that validates the template
contentVersion	Yes	Version of your template (e.g., "1.0.0.0")
parameters	No	Input values provided at deployment time
variables	No	Computed values used within the template
functions	No	User-defined functions for reusable logic
resources	Yes	The Azure resources to deploy
outputs	No	Values returned after deployment

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The $schema Field

The schema URL tells ARM which template format to use. The most common schemas are: