Azure Bicep Naming Conventions: CAF Compliant Resource Names

In Bicep, compose names with string interpolation, for example var kvName = 'kv-${workload}-${environment}-${region}-${instance}', and use take() to enforce length limits. For production templates, the community avm/utl/naming module applies each resource type’s rules for you.

If you’re writing Bicep templates, naming resources consistently is one of the first design decisions you’ll make, and one of the hardest to change later. This guide covers how to apply Microsoft’s Cloud Adoption Framework (CAF) naming conventions in Bicep, from simple string construction to reusable naming modules.

The CAF naming pattern

Microsoft’s CAF defines a standard component order:

{type}-{company}-{department}-{workload}-{environment}-{region}-{instance}

Not every resource uses every component. In practice, most teams use a simplified pattern:

{type}-{workload}-{environment}-{region}-{instance}

Examples:

Resource	Type prefix	Example name
Virtual machine	vm	vm-payments-prod-eus-001
Key Vault	kv	kv-payments-prod-eus-001
Storage account	st	stpaymentsprodeus001
App Service	app	app-payments-prod-eus-001
Container Registry	cr	crpaymentsprodeus001

Building names in Bicep

Bicep gives you string interpolation and functions to compose names dynamically. Here’s a straightforward approach:

param workload string = 'payments'
param environment string = 'prod'
param region string = 'eus'
param instance string = '001'

var kvName = 'kv-${workload}-${environment}-${region}-${instance}'
var stName = 'st${workload}${environment}${region}${instance}'

resource keyVault 'Microsoft.KeyVault/vaults@2023-07-01' = {
  name: kvName
  location: resourceGroup().location
  properties: {
    sku: {
      family: 'A'
      name: 'standard'
    }
    tenantId: subscription().tenantId
  }
}

resource storageAccount 'Microsoft.Storage/storageAccounts@2023-01-01' = {
  name: stName
  location: resourceGroup().location
  kind: 'StorageV2'
  sku: {
    name: 'Standard_LRS'
  }
}

Note that storage accounts only allow lowercase alphanumeric characters, no hyphens. The variable definition reflects this.

Using the azure-naming Bicep module

The community azure-naming Bicep module handles resource-specific constraints automatically, max lengths, allowed characters, and separator rules per resource type.

module naming 'br/public:avm/utl/naming/azure:0.1.0' = {
  name: 'naming'
  params: {
    suffix: [workload, environment, region, instance]
  }
}

resource keyVault 'Microsoft.KeyVault/vaults@2023-07-01' = {
  name: naming.outputs.keyVaultName
  location: resourceGroup().location
  properties: {
    sku: { family: 'A', name: 'standard' }
    tenantId: subscription().tenantId
  }
}

resource storageAccount 'Microsoft.Storage/storageAccounts@2023-01-01' = {
  name: naming.outputs.storageAccountName
  location: resourceGroup().location
  kind: 'StorageV2'
  sku: { name: 'Standard_LRS' }
}

This is the recommended approach for production templates, the module enforces length limits and character restrictions per resource type so you don’t have to manage them manually.

A reusable naming module (no external dependencies)

If you prefer not to use the public registry, here’s a lightweight naming module you can include directly in your repo:

// modules/naming.bicep
param workload string
param environment string
param region string
param instance string = '001'

var base = '${workload}-${environment}-${region}-${instance}'
var baseNoHyphen = toLower(replace(replace(base, '-', ''), '_', ''))

output keyVault string = take('kv-${base}', 24)
output storageAccount string = take('st${baseNoHyphen}', 24)
output appService string = take('app-${base}', 60)
output containerRegistry string = take('cr${baseNoHyphen}', 50)
output resourceGroup string = 'rg-${base}'
output virtualNetwork string = take('vnet-${base}', 64)
output keyVaultPrivateEndpoint string = take('pe-kv-${base}', 64)

Call it from your main template:

module names 'modules/naming.bicep' = {
  name: 'naming'
  params: {
    workload: 'payments'
    environment: 'prod'
    region: 'eus'
    instance: '001'
  }
}

resource keyVault 'Microsoft.KeyVault/vaults@2023-07-01' = {
  name: names.outputs.keyVault
  // resolves to: kv-payments-prod-eus-001
  location: resourceGroup().location
  properties: {
    sku: { family: 'A', name: 'standard' }
    tenantId: subscription().tenantId
  }
}

Environment and region abbreviations

Use consistent short codes across all templates:

Environments:

Environment	Abbreviation
Production	prod
Staging	stg
Development	dev
Testing	tst
UAT	uat

Regions (community convention):

Region	Abbreviation
East US	eus
East US 2	eus2
West US 2	wus2
West Europe	weu
North Europe	neu
UK South	uks
Southeast Asia	sea
Australia East	aue

Key naming constraints

Different resource types have very different constraints. These are the ones most likely to trip you up:

Resource	Max length	Allowed characters	Hyphens allowed
Storage account	24	Lowercase alphanumeric	No
Key Vault	24	Alphanumeric and hyphens	Yes
Container Registry	50	Alphanumeric	No
Virtual machine	64	Alphanumeric and hyphens	Yes
App Service	60	Alphanumeric and hyphens	Yes
Resource group	90	Alphanumeric, hyphens, underscores, periods	Yes

Note that the Windows computer name (the OS host name) is capped at 15 characters and is set separately from the 64-character VM resource name, see the VM naming guide.

AzureNamer exports ready-to-paste Bicep for all 200+ Azure resource types, either exact names or a parameterized, variable-driven file, free, no login required.

Summary

• Use string interpolation for simple templates; the azure-naming module for production
• Store naming parameters (workload, environment, region) in a params file, never hardcode them
• Watch out for storage accounts and container registries: no hyphens, lowercase only, short max length
• Standardize names from day one, retrofitting them onto existing resources is painful