[FEEDBACK REQUEST] Dotnet 10 preview

[maxday]

Today, we have published a preview AWS Lambda base container image for Dotnet 10. You can use this image to build and deploy Dotnet 10 Lambda functions if using container images as your function deployment format.

This image is public.ecr.aws/lambda/dotnet:10-preview and should not be used for production workloads. We invite you to provide your feedback on this preview image below. We are aiming to provide GA support for Dotnet 10 in Lambda, as both a base container image and a managed runtime, by the end of 2025.

Please share any feedback below! Thank you!

[jeastham1993]

@maxday this is awesome news! I'll definitely give it a try.

Is there anything specific to look out for? Or any performance improvements to be expected.

[normj]

@jeastham1993 From the Lambda libraries and runtime side the features and behavior are the same as .NET 8. Performance improvements and features will come from .NET 10 itself. That is what we would like feedback on is how well .NET 10 runs in Lambda for users.

[Gregory-Ledray]

I see no change between 8 & 10 with public.ecr.aws/lambda/dotnet:10-preview as final and mcr.microsoft.com/dotnet/sdk:10.0 AS build, running a FunctionHandler in a class decorated with [assembly: LambdaSerializer(typeof(Amazon.Lambda.Serialization.SystemTextJson.DefaultLambdaJsonSerializer))] triggered from EventBridge. Code is reading CloudWatch, pulling logs, and updating/creating output files in S3. Typical memory usage ~9.5GB and duration ~10.2 minutes.

Between dotnet 8 & dotnet 10 I saw no significant change in:

• Duration
• Billed duration
• Memory used
• Init duration

It was very easy to move from 8 to 10.

[normj]

@Gregory-Ledray Thanks for the verification!

[kopticx]

Hello, @normj . I would like to know if you plan to add compatibility with the new versions of STS, since they now have more years of support.

[jtuliani]

.NET 10 support in Lambda is now Generally Available.

https://aws.amazon.com/about-aws/whats-new/2026/01/aws-lambda-dot-net-10/
https://aws.amazon.com/blogs/compute/net-10-runtime-now-available-in-aws-lambda/

[normj]

@kopticx The Lambda policy is still to support LTS version. I am aware of the STS change policy and as a .NET guy I would love to add STS support but too early to say whether that will change anything as there are many factors/dependencies for creating a managed runtime.