Serverless Developer Guide
Related resources:
• Datadog Lambda Extension - an extension that supports submitting custom metrics, traces, and 
logs asynchronously while your Lambda function executes.
• Lambda Extensions - oﬃcial documentation
Launch functions faster with SnapStart
Lambda SnapStart for Java can improve startup performance by up to 10x at no extra cost, 
typically with no changes to your function code. The largest contributor to startup latency (often 
referred to as cold start time) is the time that Lambda spends initializing the function, which 
includes loading the function's code, starting the runtime, and initializing the function code.
With SnapStart, Lambda initializes your function when you publish a function version. Lambda 
takes a Firecracker microVM snapshot of the memory and disk state of the initialized execution 
environment, encrypts the snapshot, and caches it for low-latency access.
Note: You can use SnapStart only on published function versions and aliases that point to versions. 
You can't use SnapStart on a function's unpublished version ($LATEST).
Related resources:
• Accelerate Your Lambda Functions with Lambda SnapStart - an AWS Compute blog article by 
Jeﬀ Barr from Nov 2022 that shows the conﬁguration change and vast diﬀerence from roughly 
six seconds init time to 142 milliseconds of restore time with SnapStart
Advanced Topics 59