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Azure functions provides serverless compute for Azure. You can use Functions to build web APIs, respond to database changes, process IoT streams, manage message queues, and more. It is not like a VM where you can install additional application. The behavior of FunctionApp will depend on the code written (and packages used).
You have an option to use custom handler with Azure Functions for scenarios mentioned below:
>. Implement a function app in a language that's not currently offered out-of-the box, such as Go or Rust.
>. Implement a function app in a runtime that's not currently featured by default, such as Deno.
For more details on custom handlers, please refer to Azure Functions custom handlers
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