A low overhead kotlin/native based custom runtime for AWS Lambda with a cold start between 9 and 15ms:

REPORT Duration: 0.58 ms  Billed Duration: 12 ms  Memory Size: 128 MB  Max Memory Used: 13 MB  Init Duration: 10.48 ms

And a warm invocation <1ms:

REPORT Duration: 0.53 ms  Billed Duration: 1 ms  Memory Size: 128 MB  Max Memory Used: 16 MB

The runtime supports both x86_64 and ARM64 architectures.

import com.asyncant.aws.lambda.runtime.runLambda

fun main() = runLambda { event ->
  println("Received: $event")
  "Hello world!"
}

Or with initialization code and context:

import com.asyncant.aws.lambda.runtime.runLambda

fun main() {
  /* << Initialization code >> */

  runLambda { event, context ->
    /* << Handle event >> */
  }
}

The library can be found on Maven Central here.

implementation("com.asyncant.aws.lambda:runtime:0.9.5")

<dependency>
    <groupId>com.asyncant.aws.lambda</groupId>
    <artifactId>runtime</artifactId>
    <version>0.9.5</version>
</dependency>