Get started with AWS Lambda SnapStart for container images

This article explains how AWS Lambda SnapStart for container images reduces cold start latency from several seconds to sub-second by caching initialized execution environments.

• SnapStart takes a snapshot of the initialized execution environment during deployment and resumes from it on invocation instead of initializing from scratch
• Supported for Java 11+, Python 3.12+, and .NET 8+ using Lambda-vended base images
• Runtime hooks available for Java (CRaC), Python (snapshot_restore_py), and .NET (SnapshotRestore) to restore unique state after resume
• Enable SnapStart by updating function configuration with ApplyOn=PublishedVersions and publishing a version
• Best practices include preloading dependencies in init code, re-establishing network connections after restore, and generating unique IDs in handlers
• Pricing based on snapshot caching per function version and restore costs; available in most AWS regions except Asia Pacific (New Zealand) and (Taipei)
• Limitations: not compatible with provisioned concurrency, Amazon EFS, S3 Files, or ephemeral storage over 512 MB

SnapStart for container images enables faster startup times for latency-sensitive workloads like ML inference and interactive APIs by eliminating repeated initialization overhead.