When you create a function, language-specific trigger code is added in your project from a set of trigger templates. If you want to connect your function to other services by using input or output bindings, you have to add specific binding definitions in your function. To learn more about bindings, see Azure Functions triggers and bindings concepts.

When you develop functions locally, you need to update the function code to add bindings. For languages that use function.json, Visual Studio Code provides tooling to add bindings to a function.

::: zone pivot="programming-language-csharp"
When adding a binding to an existing function, you need to add binding-specific attributes to the function definition in code. ::: zone-end
::: zone pivot="programming-language-java"
When adding a binding to an existing function, you need to add binding-specific annotations to the function definition in code. ::: zone-end
::: zone pivot="programming-language-javascript,programming-language-powershell" When adding a binding to an existing function, you need to update the function code and add a definition to the function.json configuration file. ::: zone-end
::: zone pivot="programming-language-python" When adding a binding to an existing function, you need update the function definition, depending on your model:

You need to add binding-specific annotations to the function definition in code.

You need to update the function code and add a definition to the function.json configuration file.

::: zone-end [!INCLUDE functions-add-output-binding-example-all-langs]

Use the following table to find examples of specific binding types that you can use to guide you in updating an existing function. First, choose the language tab that corresponds to your project.

[!INCLUDE functions-bindings-code-example-chooser]

When you use Visual Studio Code to develop your function and your function uses a function.json file, the Azure Functions extension can automatically add a binding to an existing function.json file. To learn more, see Add input and output bindings.

When you develop your functions in the Azure portal, you add input and output bindings in the Integrate tab for a given function. The new bindings are added to either the function.json file or to the method attributes, depending on your language. The following articles show examples of how to add bindings to an existing function in the portal:

• Queue storage output binding
• Azure Cosmos DB output binding

• Azure Functions triggers and bindings concepts