Azure naming · Microsoft.Web/sites

func Function app

Azure Functions app. Same naming rules as App Service (<name>.azurewebsites.net).

Naming constraints

CAF abbreviationfunc
Resource typeMicrosoft.Web/sites
Length2–60 characters
CaseMixed case
Allowed charactersAlphanumerics and hyphens. Can't start or end with a hyphen.
Uniqueness Global
SeparatorHyphen
Watch out: The host ID is the app name truncated to 32 characters. Two function apps sharing a storage account and the same first 32 characters collide, so keep names unique within 32 characters.

Source: Microsoft Learn, “Naming rules and restrictions for Azure resources”, checked October 2026. Abbreviation from the Cloud Adoption Framework.

Example & copy-ready

A worked name for workload app, env prod, region weu, instance 001.

Example name
func-app-prod-weu-001 Valid
Validation regex for CI checks or pre-commit hooks (.NET and JavaScript) 
^(?=.{2,60}$)[A-Za-z0-9][A-Za-z0-9-]*[A-Za-z0-9]$
Bicep naming expression 
var name = take('func-${workload}-${env}-${region}-${instance}', 60)
Terraform local 
locals {
  name = substr(join("-", compact(["func", var.workload, var.env, var.region, var.instance])), 0, 60)
}

Azure Policy can't evaluate regular expressions, so a policy can check the func prefix but not the full format. Run the regex in your pipeline, or audit existing names on a schedule.

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Uniqueness scope

Globally unique across all of Azure — the name backs a public DNS label, so a clash with any other tenant's resource fails the deployment. Build in enough entropy (org/region/instance) to avoid collisions.

Open in the name generator

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