Matchuups: Bicep vs ARM Templates

Overview

Imagine your infrastructure as a galactic blueprint, where IaC tools shape its form. Azure Bicep, launched in 2020, is the sleek architect—a declarative language simplifying Azure deployments, used by 20% of Azure IaC users (2024).

ARM Templates, introduced in 2014, are the foundational engineers—JSON-based templates for defining Azure resources, powering 30% of Azure deployments.

Both are IaC titans, but their approaches differ: Bicep emphasizes simplicity, while ARM Templates offer raw flexibility. They’re vital for automating infrastructure, from VMs to AKS, balancing ease with power.

Fun Fact: Bicep compiles to ARM Templates under the hood!

Section 1 - Syntax and Authoring

Bicep uses concise syntax—example: deploy a storage account:

resource storageAccount 'Microsoft.Storage/storageAccounts@2022-09-01' = { name: 'mystorage' location: 'westus' sku: { name: 'Standard_LRS' } kind: 'StorageV2' }

ARM Templates use JSON—example: same storage account:

{ "type": "Microsoft.Storage/storageAccounts", "apiVersion": "2022-09-01", "name": "mystorage", "location": "westus", "sku": { "name": "Standard_LRS" }, "kind": "StorageV2" }

Bicep offers modules and type safety—think deploying 100 resources with minimal code. ARM Templates are verbose but universally compatible—think 1,000 resources in complex JSON. Bicep is developer-friendly, ARM raw.

Scenario: Bicep speeds up a startup’s IaC; ARM powers an enterprise’s legacy. Choose by complexity.

Section 2 - Modularity and Tooling

Bicep supports reusable modules—example: import a module for 100 VMs in ~10 lines. VS Code extensions provide linting and auto-complete.

ARM Templates use linked templates—example: reference a 500-line JSON for VMs. Tooling relies on Azure CLI or PowerShell, less interactive.

Scenario: Bicep simplifies 100-resource deployments; ARM handles 1,000-resource legacy systems. Bicep excels in modularity, ARM in compatibility—pick by team skills.

Key Insight: Bicep’s modules cut deployment code by 50%!

Section 3 - Deployment and Cost

Bicep deploys via CLI—example: deploy a file costing ~$0 (no direct cost). Compiles to ARM for execution.

ARM Templates deploy similarly—example: deploy a 1,000-resource JSON with ~$0 cost. Direct JSON execution, no compilation.

Practical case: Bicep suits rapid prototyping; ARM fits existing pipelines. Both are free, but Bicep reduces authoring time—optimize by dev speed.

Section 4 - Use Cases and Ecosystem

Bicep excels in new projects—example: deploy 100 AKS clusters with modules. ARM shines in legacy—think 1,000-resource enterprise deployments.

Ecosystem-wise, both integrate with Azure DevOps and GitHub Actions. Bicep pairs with VS Code; ARM with Azure Portal. Bicep is modern, ARM universal.

Practical case: Bicep accelerates a startup’s IaC; ARM maintains a bank’s infra. Choose by project stage.

Section 5 - Comparison Table

Aspect	Bicep	ARM Templates
Syntax	Concise	Verbose JSON
Modularity	Modules	Linked templates
Cost	Free	Free
Tooling	VS Code	CLI/Portal
Best For	New projects	Legacy systems

Bicep suits modern IaC; ARM excels in legacy compatibility. Choose by team skills.

Conclusion

Azure Bicep and ARM Templates are IaC powerhouses with distinct strengths. Bicep offers a concise, developer-friendly language for rapid infrastructure deployment, ideal for modern projects and small teams. ARM Templates provide raw, JSON-based flexibility for complex, legacy systems, perfect for enterprises with existing pipelines. Consider project stage (new vs. legacy), team skills (developer vs. DevOps), and complexity.

For new IaC, Bicep shines; for legacy deployments, ARM delivers. Pair Bicep with VS Code or ARM with Azure DevOps for optimal results. Test both—both are free to author and deploy, making prototyping seamless.

Pro Tip: Use Bicep’s decompile to convert ARM JSON to Bicep!

Tech Matchups: Azure Bicep vs ARM Templates