Topaz vs Azurite: what actually works locally and what doesn't
If you have ever written a line of Azure code on a laptop, you have used Azurite. It is the official local emulator for Azure Storage, ships in every Visual Studio install, and runs unchanged in tens of thousands of CI pipelines. For Storage-only workloads it is an excellent tool — Microsoft maintains it, Azure SDKs target it, and the parity with the real Azure Storage REST API is strong.
The problem is that real applications stop at Azure Storage roughly never. The moment you reach for a secret in Key Vault, publish a message to Service Bus, push an image to a Container Registry, or want a DefaultAzureCredential chain that does not silently fall back to interactive browser auth, Azurite has nothing to offer. You are left bolting together a Service Bus emulator from a community Docker image, mocking the Key Vault SDK in tests, and hoping that the way your CI fakes Entra tokens does not drift away from how production behaves.
Topaz is a single .NET 10 binary that emulates Azure Storage, Key Vault, Service Bus, Event Hubs, Container Registry, Managed Identity, RBAC, ARM, and a working Entra ID layer in one process. This post is an honest comparison between the two, focused on what developers who already know Azurite actually run into.