Validate Azure resource names against naming rules and length constraints by resource type.
Last verified: May 2026
Output will appear here...Azure resource naming rules are notoriously inconsistent across resource types — storage accounts allow only lowercase alphanumeric characters with a 24-character limit, while resource groups allow hyphens, underscores, and periods with up to 90 characters. Virtual machines have different limits on Windows (15 characters) versus Linux (64 characters). This validator checks your proposed resource name against the specific rules for your chosen resource type, catching issues like invalid characters, length violations, and reserved names before you encounter Azure Resource Manager errors during deployment.
Resources that create public DNS endpoints must be globally unique. This includes storage accounts (storageaccount.blob.core.windows.net), key vaults (vaultname.vault.azure.net), web apps (appname.azurewebsites.net), Cosmos DB accounts, and Azure SQL servers. Resources like VMs, NICs, and NSGs only need to be unique within their resource group. Globally unique names are the most constrained and most likely to fail during deployment.
Storage account names become part of the DNS hostname (e.g., mystorageaccount.blob.core.windows.net) and must follow DNS label rules, which Azure restricts further to lowercase alphanumeric only. The 24-character limit is an Azure-specific constraint designed to keep URLs manageable. This is one of the most restrictive naming rules in Azure and frequently catches teams that use hyphens in their naming conventions for other resource types.
Your IaC pipeline generates resource names by templating like st-{env}-{app}-{region}. A new environment named 'production-eu-west' pushes the storage account name past 24 characters and the deploy fails after 11 minutes of provisioning because storage accounts are validated late in the ARM evaluation. You add this validator as a pre-commit hook on the IaC repo: now invalid names fail in 100ms locally instead of after 11 minutes in CI, saving the team hours per week.
The validator loads a per-resource-type rule set covering allowed character class, length range, case sensitivity, and global-vs-resource-group-scoped uniqueness. Resource types with DNS-derived names (storage accounts, key vaults, web apps) get stricter validation including DNS label rules. The tool runs the regex check first for fast failure, then length, then surfaces the most specific rule violated rather than a generic 'invalid name'.
Storage account names are global across all of Azure, like S3 bucket names in AWS. Pre-validate before running az storage account create — failed creates due to name collisions don't always clean up gracefully and can leave orphaned resources visible in the portal.
Adopt the Cloud Adoption Framework (CAF) abbreviation prefixes (st for storage, kv for key vault, vm for virtual machine, etc.) for resource naming. This makes ARM template error messages instantly identifiable by resource type and survives copy-paste between environments.
Windows VM computer names are limited to 15 characters because of legacy NetBIOS, but the *Azure resource name* can be longer. The two don't have to match — many teams set a long descriptive Azure name and a short hashed computer name to satisfy both.
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