Introducing public preview runtimes on AWS Lambda, starting with Node.js 26 and Python 3.15
Compute Blog
AWS Lambda introduces public preview runtimes, enabling developers to test Node.js 26 and Python 3.15 before general availability and provide feedback while breaking changes are still possible.
- Preview runtimes available in all AWS commercial regions, GovCloud, and China regions
- Functions automatically graduate to GA with no action required when runtime reaches stable release
- Same runtime identifiers as GA versions (nodejs26.x, python3.15) ensure seamless transition
- Preview runtimes follow same patching cadence as GA runtimes with all Lambda features supported
- Breaking changes may occur during preview; not covered by Lambda SLA or AWS Support
- Functions billed at standard Lambda rates with no additional cost
- Feedback collected via dedicated GitHub issues for each runtime
- Node.js 26 GA targeted within two months of October 2026 Active LTS release
Public preview runtimes allow real-world testing and feedback collection before GA, benefiting customers, partners, and upstream language communities.
The AWS News Feed is currently looking for gold sponsors. If you want to support the AWS community and reach a large audience of AWS professionals, consider sponsoring the AWS News Feed.
The AWS News Feed is currently looking for silver sponsors. If you want to support the AWS community and reach a large audience of AWS professionals, consider sponsoring the AWS News Feed.