Azure Service Name Requirements
The requirements for Azure service names are somewhat varied. Also, they generally don't appear to be documented anywhere besides the validation message displayed when the requirements are violated. This is an attempt to consolidate service name requirements as a resource for defining naming conventions or building automation scripts.
| Service | Maximum Length | Character Set Restrictions | First/Last character restrictions | Unique Within |
| Subscription | 64 | letters, numbers, and underscores | None | Account? |
| Resource Group | 64 | letters, numbers, and underscores | Must begin with a letter | Subscription |
| Hosting Plan | 39 | letters, numbers, and underscores | None | Subscription |
| Website Name | 59 | letters, numbers, and hyphens | Must begin and end with a letter | Azure |
| Web Job Name | 29 | letters, number, hyphens, spaces, and underscores | None | Website |
| Deployment Slot | 59 | letters, number, and hyphens | Cannot end with a hyphen | Website |
| Storage Account | 24 | lowercase letters | None | Azure |
| Alert Name | 31 | letters, numbers, commas, periods, and spaces | None | Service |
| Virtual Machine | 15 | Azure | ||
| SQL Database Server | 63 | lowercase letters, numbers, and hyphens | Cannot start or end with a hyphen | Azure |
| SQL Database | 128 | all except: < > * % & : \ / ? | Cannot end with a period | SQL DB Server |
| SQL DB Firewall Rule1 | 128 | all except: < > * % & : \ / ? | Cannot end with a period |
SQL DB Server |
| Redis Cache | 63 | letters, numbers, and hyphens | Cannot start or end with a hyphen |
Azure |
1 This may apply to all firewall rules