ST-2026-222 · Runtimes & developer platforms
AWS Lambda adds a public-preview lifecycle for managed runtimes
AWS Lambda introduced managed runtimes in public preview, starting with Node.js 26 and Python 3.15, creating a pre-GA lifecycle in which preview runtimes may receive breaking changes and later graduate automatically to GA under the same runtime identifier.
Previous state
AWS Lambda managed runtimes were launched directly as generally available releases rather than through a public-preview managed-runtime phase.
Current state
AWS Lambda managed runtimes can now be released in public preview before GA. Node.js 26 and Python 3.15 are the first preview runtimes; preview runtimes may receive breaking changes, are outside the Lambda SLA and AWS Technical Support, use the same runtime identifier as eventual GA, and graduate automatically when GA is reached.
Affected users
Who needs to care
AWS Lambda users, observability providers, infrastructure-as-code tools and deployment frameworks evaluating Node.js 26, Python 3.15 or future managed runtimes during their pre-GA lifecycle.
Required response
What to do
Treat preview managed runtimes as non-production, test workload and tooling compatibility before GA, report issues during preview, and do not infer production support or SLA coverage until AWS announces GA.
Evidence boundary
What the source does not prove
AWS proves the public-preview managed-runtime lifecycle and current Node.js 26/Python 3.15 preview availability. It does not make those runtimes generally available, does not provide Lambda SLA or AWS Technical Support coverage during preview, and does not establish a GA date.
Lifecycle history
Dated event sequence
- Managed-runtime public preview introduced
AWS introduced the public-preview lifecycle with Node.js 26 and Python 3.15 as the first preview managed runtimes.
Evidence ledger
First-party sources
- 01AWS — AWS Lambda introduces managed runtimes in public preview for Node.js 26 and Python 3.15
Official AWS What's New · 2026-08-25
Open official source ↗