Lambda runtimes

Lambda supports multiple languages through the use of runtimes. A runtime provides a language-specific environment that relays invocation events, context information, and responses between Lambda and the function. You can use runtimes that Lambda provides, or build your own.

Each major programming language release has a separate runtime, with a unique runtime identifier, such as nodejs20.x or python3.13. To configure a function to use a new major language version, you need to change the runtime identifier. Since AWS Lambda cannot guarantee backward compatibility between major versions, this is a customer-driven operation.

For a function defined as a container image, you choose a runtime and the Linux distribution when you create the container image. To change the runtime, you create a new container image.

When you use a .zip file archive for the deployment package, you choose a runtime when you create the function. To change the runtime, you can update your function's configuration. The runtime is paired with one of the Amazon Linux distributions. The underlying execution environment provides additional libraries and environment variables that you can access from your function code.

Lambda invokes your function in an execution environment. The execution environment provides a secure and isolated runtime environment that manages the resources required to run your function. Lambda re-uses the execution environment from a previous invocation if one is available, or it can create a new execution environment.

To use other languages in Lambda, such as Go or Rust, use an OS-only runtime. The Lambda execution environment provides a runtime interface for getting invocation events and sending responses. You can deploy other languages by implementing a custom runtime alongside your function code, or in a layer.

Supported runtimes

The following table lists the supported Lambda runtimes and projected deprecation dates. After a runtime is deprecated, you're still able to create and update functions for a limited period. For more information, see Runtime use after deprecation. The table provides the currently forecasted dates for runtime deprecation. These dates are provided for planning purposes and are subject to change.

Lambda keeps managed runtimes and their corresponding container base images up to date with patches and support for minor version releases. For more information see Lambda runtime updates.

Lambda continues to support the Go programming language after deprecation of the Go 1.x runtime. For more information, see Migrating AWS Lambda functions from the Go1.x runtime to the custom runtime on Amazon Linux 2 on the AWS Compute Blog.

All supported Lambda runtimes support both x86_64 and arm64 architectures.

New runtime releases

Lambda provides managed runtimes for new language versions only when the release reaches the long-term support (LTS) phase of the language's release cycle. For example, for the Node.js release cycle, when the release reaches the Active LTS phase.

Before the release reaches the long-term support phase, it remains in development and can still be subject to breaking changes. Lambda applies runtime updates automatically by default, so breaking changes to a runtime version could stop your functions from working as expected.

Lambda doesn't provide managed runtimes for language versions which aren't scheduled for LTS release.

The following list shows the target launch month for upcoming Lambda runtimes. These dates are indicative only and subject to change.

Runtime deprecation policy

Lambda runtimes for .zip file archives are built around a combination of operating system, programming language, and software libraries that are subject to maintenance and security updates. Lambda’s standard deprecation policy is to deprecate a runtime when any major component of the runtime reaches the end of community long-term support (LTS) and security updates are no longer available. Most usually, this is the language runtime, though in some cases, a runtime can be deprecated because the operating system (OS) reaches end of LTS.

After a runtime is deprecated, AWS may no longer apply security patches or updates to that runtime, and functions using that runtime are no longer eligible for technical support. Such deprecated runtimes are provided ‘as-is’, without any warranties, and may contain bugs, errors, defects, or other vulnerabilities.

To learn more about managing runtime upgrades and deprecation, see the following sections and Managing AWS Lambda runtime upgrades on the AWS Compute Blog.

Shared responsibility model

Lambda is responsible for curating and publishing security updates for all supported managed runtimes and container base images. By default, Lambda will apply these updates automatically to functions using managed runtimes. Where the default automatic runtime update setting has been changed, see the runtime management controls shared responsibility model. For functions deployed using container images, you're responsible for rebuilding your function's container image from the latest base image and redeploying the container image.

When a runtime is deprecated, Lambda’s responsibility for updating the managed runtime and container base images ceases. You are responsible for upgrading your functions to use a supported runtime or base image.

In all cases, you are responsible for applying updates to your function code, including its dependencies. Your responsibilities under the shared responsibility model are summarized in the following table.

Runtime use after deprecation

After a runtime is deprecated, AWS may no longer apply security patches or updates to that runtime, and functions using that runtime are no longer eligible for technical support. Such deprecated runtimes are provided ‘as-is’, without any warranties, and may contain bugs, errors, defects, or other vulnerabilities. Functions that use a deprecated runtime may also experience degraded performance or other issues, such as a certificate expiry, that can cause them to stop working properly.

For at least 30 days after a runtime is deprecated, you’re still able to create new Lambda functions using that runtime. Starting from 30 days after deprecation, Lambda begins blocking the creation of new functions.

For at least 60 days after a runtime is deprecated, you’re still able to update function code and configuration for existing functions. Starting from 60 days after deprecation, Lambda begins blocking the update of function code and configuration for existing functions.

You can update a function to use a newer supported runtime indefinitely after a runtime is deprecated. You should test that your function works with the new runtime before applying the runtime change in production environments, since you will not be able to revert to the deprecated runtime once the 60-day period has passed. We recommend using function versions and aliases to enable safe deployment with rollback.

Note that the exact length of time for which you can continue to create and update functions isn’t fixed. This period can vary for each deprecation and for different AWS Regions. Nominal dates for the blocking of function creates and updates are provided in the Supported Runtimes table in the first section of this page. Lambda will not start blocking function creates or updates before the dates given in this table.

You can continue to invoke your functions indefinitely after the runtime is deprecated. However, AWS strongly recommends that you migrate functions to a supported runtime so that your functions continue to receive security patches and remain eligible for technical support.

Receiving runtime deprecation notifications

When a runtime approaches its deprecation date, Lambda sends you an email alert if any functions in your AWS account use that runtime. Notifications are also displayed in the AWS Health Dashboard and in AWS Trusted Advisor.

Deprecated runtimes

The following runtimes have reached end of support:

In almost all cases, the end-of-life date of a language version or operating system is known well in advance. The following links give end-of-life schedules for each language that Lambda supports as a managed runtime.