Infrastructure as Code: Why ARM Templates Are Still Worth Learning in 2025

Every time I mention ARM templates in 2025, someone inevitably says "just use Terraform" or "Bicep is the future." They're not wrong. But they're missing something important.

Understanding ARM templates makes you better at everything else.

The Foundation Nobody Wants to Learn

Here's a truth most cloud engineers won't admit: Bicep compiles to ARM. Terraform's AzureRM provider ultimately calls the same ARM APIs. When something breaks, the error messages often reference ARM concepts.

If you don't understand ARM, you're debugging blind.

What ARM Templates Actually Teach You

1. How Azure Really Works

ARM templates expose Azure's resource model directly. You see:

• How resources relate to each other through dependencies
• What properties each resource type actually supports
• How Azure handles deployment ordering and parallelization

This knowledge transfers to every other IaC tool.

2. Reading Microsoft Documentation

Microsoft's ARM template reference is the source of truth for Azure resources. Even when using Terraform, I regularly check the ARM docs to understand what's possible.

Once you can read ARM JSON, the docs become infinitely more useful.

3. Troubleshooting Deployments

When a deployment fails, Azure shows you the ARM-level error. Understanding the template structure helps you:

• Identify which resource failed
• Understand dependency chains
• Interpret cryptic error messages

The Practical Approach

I'm not saying you should write ARM templates daily. Here's what I actually recommend:

Start with ARM (1-2 weeks)

• Deploy a basic VM with networking
• Understand parameters, variables, and outputs
• Learn how dependencies work

Move to Bicep (ongoing)

• Same concepts, cleaner syntax
• Direct ARM compilation
• Better tooling and IntelliSense

Add Terraform When Needed

• Multi-cloud scenarios
• Teams already using it
• Specific module requirements

A Simple Exercise

Before you dismiss ARM, try this:

1. Deploy a storage account using the Azure Portal
2. Export the ARM template
3. Read through it and understand every line
4. Modify one property and redeploy

You'll learn more about Azure storage in 30 minutes than hours of video tutorials.

The Uncomfortable Truth

The engineers I respect most can work at multiple abstraction levels. They use Terraform for efficiency but can drop down to ARM when debugging. They write Bicep but understand what it compiles to.

Tools change. Fundamentals don't.

ARM templates aren't sexy. But understanding them will make you better at whatever IaC tool you choose to use.