Changing lambda function's architecture from x86 to arm64

[user-preethy]

Hi,

Is there any issue with changing the Lambda architecture—especially the fulfillment Lambdas—from x86_64 to arm64?
What kinds of problems could this cause?
Will this change reduce the overall cost of the solution?

If not, could you please suggest some effective measures to reduce the overall cost?

[michaelin-96]

Hi @user-preethy,

The solution currently runs on nodejs24.x and python3.14 Lambda runtimes, both of which support arm64 architecture. However, we are unsure if there are any potential migration issues with switching over to arm64. We recommend that if you plan to make this change, you test it in a test environment with proper backups in place.

According to Lambda documentation, switching over to arm64 should provide approximately 20% reduction in cost. However, if cost is a main concern, I would first look into how you configure your OpenSearch nodes, as a significant portion of the cost comes from deploying those instances. See the cost documentation for reference.