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Creating a function in Kotlin

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Updated at September 10, 2025

Create and run a user welcome function in Kotlin.

Before you start

Create a folder in Yandex Cloud.

Create a function

  1. In the management console, select the folder where you want to create a function.
  2. Select Cloud Functions.
  3. Click Create function.
  4. Enter the function name: kotlin-function.
  5. Click Create.

If you do not have the Yandex Cloud CLI installed yet, install and initialize it.

By default, the CLI uses the folder specified when creating the profile. To change the default folder, use the yc config set folder-id <folder_ID> command. You can also set a different folder for any specific command using the --folder-name or --folder-id parameter.

To create a function, run the command:

yc serverless function create --name=kotlin-function

Result:

id: d4eek526ai42********
folder_id: b1gt6g8ht345********
created_at: "2024-12-19T20:02:56.039Z"
name: kotlin-function
http_invoke_url: https://functions.yandexcloud.net/d4eek526ai42********
status: ACTIVE

You can create a function using the create.

Create the first version of the function

To create a function version, you can use one of the code upload formats. A ZIP archive will be used for the example.

Warning

Files larger than 3.5 MB should be uploaded via Object Storage. For more information about limits, see Quotas and limits in Cloud Functions.

Prepare a ZIP archive with the function code

  1. Save the following code to a file named Handler.kt:

    data class Request(
    val httpMethod: String?,
    val headers: Map<String, String> = mapOf(),
    val body: String = ""
)

data class Response(
    val statusCode: Int,
    val body: String
)

fun handle(request: Request): Response {
    return Response(200, "Hello World!")
}

  2. Add Handler.kt to the hello-kotlin.zip archive.

Create a function version

  1. In the management console, select the folder containing the function.
  2. Select Cloud Functions.
  3. Select the kotlin-function function.
  4. Under Last version, click Сreate in editor.
  5. Select the Kotlin 2.0 runtime environment.
  6. Disable the Add files with code examples option and click Continue.
  7. Set the version parameters:
    • Method: ZIP archive
    • File: Attach hello-kotlin.zip
    • Entry point: Handler
    • Timeout: 3
    • Memory: 128 MB
    • Service account: Not selected
  8. Click Save changes.

If you do not have the Yandex Cloud CLI installed yet, install and initialize it.

By default, the CLI uses the folder specified when creating the profile. To change the default folder, use the yc config set folder-id <folder_ID> command. You can also set a different folder for any specific command using the --folder-name or --folder-id parameter.

To create a function version, run the command:

yc serverless function version create \
  --function-name=kotlin-function \
  --runtime kotlin20 \
  --entrypoint Handler \
  --memory 128m \
  --execution-timeout 3s \
  --source-path ./hello-kotlin.zip

Where:

  • --function-name: Name of the function whose version you want to create.
  • --runtime: Runtime environment.
  • --entrypoint: Entry point in <function_file_name>.<handler_name> format.
  • --memory: Amount of RAM.
  • --execution-timeout: Maximum function running time before timeout.
  • --source-path: ZIP archive with the function code and required dependencies.

Result:

done (10s)
id: d4ektme8jo2d********
function_id: d4e9arrf01oh********
created_at: "2024-12-19T20:22:15.942Z"
runtime: kotlin20
entrypoint: Handler
resources:
  memory: "134217728"
execution_timeout: 3s
image_size: "4096"
status: ACTIVE
tags:
  - $latest
log_options:
  folder_id: b1gt6g8ht345********
concurrency: "1"

You can create a function version using the createVersion.

Invoke the function

Note

To allow any user to invoke your function, make it public. For more information about access rights, see Access management in Cloud Functions.

  1. In the management console, select the folder containing the function.

  2. Select Cloud Functions.

  3. Select a function.

  4. Navigate to the Testing tab.

  5. In the Version tag field, specify $latest to invoke the latest function version.

  6. In the Payload template field, select No template.

  7. In the Payload field, enter:

    {}

  8. Click Run test.

  9. You will see the testing status under Test result in the Function status field. Important: Maximum function execution time before timeout (including original initialization at first invocation) is 10 minutes.

  10. You will see the function execution result in the Function output field:

    {
    "statusCode": 200,
    "body": "Hello World!"
}

To invoke a function, run this command:

yc serverless function invoke <function_ID> -d '{}'

Result:

{"statusCode":200,"body":"Hello World!"}

The function version with the $latest tag is invoked by default.

You can view the function invocation link on the Overview tab, in the Link to invoke field.

For security reasons, you can only invoke a function via HTTPS. Invoke it as a regular HTTP request by pasting the link into the browser address bar and adding the name parameter to the URL:

https://functions.yandexcloud.net/<function_ID>

The following response will appear on the page:

Hello World!

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