# Synthetics runtime versions


When you create or update a canary, you choose a Synthetics runtime version for the canary. A Synthetics runtime is a combination of the Synthetics code that calls your script handler, and the Lambda layers of bundled dependencies.

CloudWatch Synthetics currently supports runtimes that use Node.js, Python, or Java languages. The frameworks supported are Puppeteer, Playwright, and Selenium.

We recommend that you always use the most recent runtime version for your canaries, to be able to use the latest features and updates made to the Synthetics library.

**Please note**: whenever you run a canary to use the new version of the Synthetics runtime, all Synthetics library functions that your canary uses are also automatically moved to the same version of NodeJS that the Synthetics runtime supports.

**Topics**
+ [

# Runtime versions using Java
](CloudWatch_Synthetics_Library_Java.md)
+ [

# Runtime versions using Node.js and Playwright
](CloudWatch_Synthetics_Library_nodejs_playwright.md)
+ [

# Runtime versions using Node.js and Puppeteer
](CloudWatch_Synthetics_Library_nodejs_puppeteer.md)
+ [

# Runtime versions using Python and Selenium Webdriver
](CloudWatch_Synthetics_Library_python_selenium.md)
+ [

# Runtime versions using Node.js
](CloudWatch_Synthetics_Library_Nodejs.md)
+ [

# Runtime versions support policy
](CloudWatch_Synthetics_Runtime_Support_Policy.md)
+ [

# Runtime versions update
](CloudWatch_Synthetics_Runtime_Version_Update.md)

# Runtime versions using Java


The following section contains information about the CloudWatch Synthetics runtime versions for Java. This runtime does not have any browser or framework included.

The naming convention for these runtime versions is `syn-language -majorversion.minorversion`. 

## syn-java-1.0


**Major dependencies**:
+ Amazon Lambda runtime Java 21

 **Features** 
+ *CloudWatch Logs integration* – You can query and filter for logs through the CloudWatch Synthetics console. Each log message contains unique ` canaryRunId`, making it easy to search for logs for a particular canary run.
+ *Metrics* – You can monitor canary run success percentage and duration through CloudWatch metrics. You can also configure alarms to alert you when canaries detect issues.
+ *Canary artifacts* - Each canary run uploads a detailed report corresponding to the run and the steps in the run which can be accessed through Amazon S3.
+ *Support for traces* - You can emit traces for all the requests made by the canary through X-Ray. Each canary run is associated with one trace Id.

# Runtime versions using Node.js and Playwright


The following sections contain information about the CloudWatch Synthetics runtime versions for Node.js and Playwright. Playwright is an open-source automation library for browser testing. For more information about Playwright, see [ https://playwright.dev/](https://playwright.dev) 

The naming convention for these runtime versions is `syn-language -framework-majorversion. minorversion`. 

## syn-nodejs-playwright-6.0


**Important**  
Starting Synthetics `syn-nodejs-playwright-5.1` and later, Synthetics runtime uses the new namespace. Please migrate the canary script to use the new namespace. Legacy namespace will be deprecated in a future release.  
@amzn/synthetics-playwright → @aws/synthetics-playwright

**Major dependencies**:
+ Amazon Lambda runtime Node.js 22.x
+ Playwright version 1.58.2
+ Playwright/test version 1.58.2
+ Chromium version 145.0.7632.77
+ Firefox version 146.0.1

 **Changes in syn-nodejs-playwright-6.0** 
+ Applied security patches and updated Playwright and browser versions. 

For more information, see the following:
+  [Playwright change log ](https://playwright.dev/docs/release-notes) 
+  [Playwright API reference](https://playwright.dev/docs/api/class-playwright) 

## Previous runtime versions for Node.js and Playwright


The following earlier runtime versions for Node.js and Playwright are still supported. 

### syn-nodejs-playwright-5.1


**Major dependencies**:
+ Amazon Lambda runtime Node.js 22.x
+ Playwright version 1.57.0
+ Playwright/test version 1.57.0
+ Chromium version 143.0.7499.169
+ Firefox version 142.0.1

 **Changes in syn-nodejs-playwright-5.1** 
+ Synthetics runtime namespace migration. 
+ Type definition is available in [npm Registry](https://www.npmjs.com/package/@aws/synthetics-playwright). Please ensure the type definition package version matches your canary's runtime version.

For more information, see the following:
+  [Playwright change log ](https://playwright.dev/docs/release-notes) 
+  [Playwright API reference](https://playwright.dev/docs/api/class-playwright) 

### syn-nodejs-playwright-5.0


**Major dependencies**:
+ Amazon Lambda runtime Node.js 22.x
+ Playwright version 1.57.0
+ Playwright/test version 1.57.0
+ Chromium version 143.0.7499.4
+ Firefox version 142.0.1

 **Changes in syn-nodejs-playwright-5.0** 
+ Applied security patches and updated Playwright and browser versions. 

For more information, see the following:
+  [Playwright change log ](https://playwright.dev/docs/release-notes) 
+  [Playwright API reference](https://playwright.dev/docs/api/class-playwright) 

### syn-nodejs-playwright-4.0


**Major dependencies**:
+ Amazon Lambda runtime Node.js 22.x
+ Playwright version 1.55.0
+ Playwright/test version 1.55.0
+ Chromium version 140.0.7339.16
+ Firefox version 141.0

 **Changes in syn-nodejs-playwright-4.0** 
+ Applied security patches and updated Playwright and browser versions. 

For more information, see the following:
+  [Playwright change log ](https://playwright.dev/docs/release-notes) 
+  [Playwright API reference](https://playwright.dev/docs/api/class-playwright) 

### syn-nodejs-playwright-3.0


**Major dependencies**:
+ Amazon Lambda runtime Node.js 20.x
+ Playwright version 1.53.0
+ Playwright/test version 1.53.0
+ Chromium version 138.0.7204.168

 **Changes in syn-nodejs-playwright-3.0** 
+ Multi-browser support – You can now run your nodejs puppeteer canaries in either Firefox or Chrome
+ Support for visual monitoring

For more information, see the following:
+  [Playwright change log ](https://playwright.dev/docs/release-notes) 
+  [Playwright API reference](https://playwright.dev/docs/api/class-playwright) 

### syn-nodejs-playwright-2.0


**Major dependencies**:
+ Amazon Lambda runtime Node.js 20.x
+ Playwright version 1.49.1
+ Playwright/test version 1.49.1
+ Chromium version 131.0.6778.264

 **Changes in syn-nodejs-playwright-2.0** 
+ The mismatch between total duration and sum of timings for a given request in HAR file is fixed.
+ Supports dry runs for the canary which allows for adhoc executions or performing a safe canary update.

For more information, see the following:
+  [Playwright change log ](https://playwright.dev/docs/release-notes) 
+  [Playwright API reference](https://playwright.dev/docs/api/class-playwright) 

### syn-nodejs-playwright-1.0


**Major dependencies**:
+ Amazon Lambda runtime Node.js 20.x
+ Playwright version 1.44.1
+ Playwright/test version 1.44.1
+ Chromium version 126.0.6478.126

**Features**:
+ **PlayWright support** – You can write canary scripts by using the Playwright automation framework. You can bring your existing Playwright scripts to run as canaries, and enhance them with Amazon monitoring capabilities. 
+ **CloudWatch Logs integration** – You can query and filter for logs through the CloudWatch Synthetics console. Each log message contains unique `canaryRunId`, making it easy to search for logs for a particular canary run. 
+ **Metrics and canary artifacts** – You can monitor canary run pass rate through CloudWatch metrics, and configure alarms to alert you when canaries detect issues. 
+ **Screenshots and steps association** – You can capture screenshots using native Playwright functionality to visualize the stages of a canary script on each run. Screenshots are automatically associated with canary steps, and are uploaded to Amazon S3 buckets. 
+ **Multiple tabs**– You can create canaries that open multiple browser tabs, and access screenshots from each tab. You can create multi-tab and multi-step user workflows in Synthetics. 

# Runtime versions using Node.js and Puppeteer


The first runtime version for Node.js and Puppeteer was named `syn-1.0`. Later runtime versions have the naming convention `syn-language -majorversion.minorversion`. Starting with `syn-nodejs-puppeteer-3.0`, the naming convention is `syn- language-framework-majorversion .minorversion` 

An additional `-beta` suffix shows that the runtime version is currently in a beta preview release.

Runtime versions with the same major version number are backward compatible. 

The Lambda code in a canary is configured to have a maximum memory of 1 GB. Each run of a canary times out after a configured timeout value. If no timeout value is specified for a canary, CloudWatch chooses a timeout value based on the canary's frequency. If you configure a timeout value, make it no shorter than 15 seconds to allow for Lambda cold starts and the time it takes to boot up the canary instrumentation.

## syn-nodejs-puppeteer-15.0


`syn-nodejs-puppeteer-15.0` is the most recent Synthetics runtime for Node.js and Puppeteer. 

**Important**  
Starting Synthetics `syn-nodejs-puppeteer-13.1` and later, Synthetics runtime uses the new namespace. Please migrate the canary script to use new namespaces. Legacy namespaces will be deprecated in a future release.  
Synthetics → @aws/synthetics-puppeteer
SyntheticsLink → @aws/synthetics-link
SyntheticsLogger → @aws/synthetics-logger
SyntheticsLogHelper → @aws/synthetics-log-helper
BrokenLinkCheckerReport → @aws/synthetics-broken-link-checker-report

**Important**  
Synthetics runtime `syn-nodejs-puppeteer-11.0` and later versions support only the following step-level configuration overrides:  
 `screenshotOnStepStart` 
 `screenshotOnStepSuccess` 
 `screenshotOnStepFailure` 
 `stepSuccessMetric` 
 `stepDurationMetric` 
 `continueOnStepFailure/continueOnHttpStepFailure` 
 `stepsReport` 

For more information, see the following:
+  [Puppeteer Change log](https://pptr.dev/CHANGELOG#24375-2026-02-19) 
+  [Puppeteer API reference](https://github.com/puppeteer/puppeteer/blob/puppeteer-v24.37.5/docs/api/index.md) 

**Major dependencies**:
+ Lambda runtime Node.js 22.x
+ Puppeteer-core version 24.37.5
+ Chromium version 145.0.7632.77
+ Firefox version 147.0.4

 **Changes in syn-nodejs-puppeteer-15.0** 
+ Applied security patches and updated Puppeteer and browser versions.
+ Fixed bug where continueOnHttpStepFailure was not being honored, causing canary runs to be incorrectly marked as successful despite HTTP step failures occurring.

## Previous runtime versions for Node.js and Puppeteer


The following earlier runtime versions for Node.js and Puppeteer are still supported. 

### syn-nodejs-puppeteer-14.0


For more information, see the following:
+  [Puppeteer Change log](https://pptr.dev/CHANGELOG#24340-2025-12-19) 
+  [Puppeteer API reference](https://github.com/puppeteer/puppeteer/blob/puppeteer-v24.34.0/docs/api/index.md) 

**Major dependencies**:
+ Lambda runtime Node.js 22.x
+ Puppeteer-core version 24.34.0
+ Chromium version 143.0.7499.169
+ Firefox version 146.x

 **Changes in syn-nodejs-puppeteer-14.0** 
+ Applied security patches and updated Puppeteer and browser versions.

### syn-nodejs-puppeteer-13.1


`syn-nodejs-puppeteer-13.1` is the most recent Synthetics runtime for Node.js and Puppeteer. 

For more information, see the following:
+  [Puppeteer Change log](https://pptr.dev/CHANGELOG#24250-2025-10-15) 
+  [Puppeteer API reference](https://github.com/puppeteer/puppeteer/blob/puppeteer-v24.2.0/docs/api/index.md) 

**Major dependencies**:
+ Lambda runtime Node.js 22.x
+ Puppeteer-core version 24.25.0
+ Chromium version 142.0.7444.175
+ Firefox version 145.x

 **Changes in syn-nodejs-puppeteer-13.1** 
+ Synthetics runtime namespace migration.
+ Type definitions are available in npm Registry. Please ensure the type definition package version matches your canary's runtime version.
  +  [ @aws/synthetics-puppeteer](https://www.npmjs.com/package/@aws/synthetics-puppeteer) 
  +  [ @aws/synthetics-link](https://www.npmjs.com/package/@aws/synthetics-link) 
  +  [ @aws/synthetics-broken-link-checker-report](https://www.npmjs.com/package/@aws/synthetics-broken-link-checker-report) 
  +  [ @aws/synthetics-log-helper](https://www.npmjs.com/package/@aws/synthetics-log-helper) 
  +  [ @aws/synthetics-logger](https://www.npmjs.com/package/@aws/synthetics-logger) 

### syn-nodejs-puppeteer-13.0


For more information, see the following:
+  [Puppeteer Change log](https://pptr.dev/CHANGELOG#24250-2025-10-15) 
+  [Puppeteer API reference](https://github.com/puppeteer/puppeteer/blob/puppeteer-v24.2.0/docs/api/index.md) 

**Major dependencies**:
+ Lambda runtime Node.js 22.x
+ Puppeteer-core version 24.25.0
+ Chromium version 142.0.7444.175
+ Firefox version 145.x

 **Changes in syn-nodejs-puppeteer-13.0** 
+ Applied security patches and updated Puppeteer and browser versions.
+ Bug fix – Fixed intermittent runtime extension crash issue caused by concurrent map access

### syn-nodejs-puppeteer-12.0


For more information, see the following:
+  [Puppeteer Change log](https://pptr.dev/CHANGELOG#24221-2025-09-23) 
+  [Puppeteer API reference](https://github.com/puppeteer/puppeteer/blob/puppeteer-v24.22.1/docs/api/index.md) 

**Major dependencies**:
+ Lambda runtime Node.js 22.x
+ Puppeteer-core version 24.22.1
+ Chromium version 140.0.7339.185
+ Firefox version 143.0.1

 **Changes in syn-nodejs-puppeteer-12.0** 
+ Applied security patches and updated Puppeteer and browser versions.
+ Bug fix for Restricted header redaction – Fixed an issue where in some situations restricted headers were not being redacted in executeHttpStep(). Behavior is now consistent with Puppeteer 10.0.
+ Bug fix for includeResponseBody configuration – Fixed an issue where HAR file generation can misapply the includeResponseBody configuration setting in certain situations. HAR now ensures response bodies are excluded when setting is configured.
+ Request capture lifecycle fixed – Fixed an issue where in some situations the HTTP request capturer may cause continuous aggregation of requests. Recording now terminates correctly after each step execution.

### syn-nodejs-puppeteer-11.0


For more information, see the following:
+  [Puppeteer Change log](https://pptr.dev/CHANGELOG) 
+  [Puppeteer API reference](https://github.com/puppeteer/puppeteer/blob/puppeteer-v24.2.0/docs/api/index.md) 

**Major dependencies**:
+ Lambda runtime Node.js 20.x
+ Puppeteer-core version 24.15.0
+ Chromium version 138.0.7204.168

 **Changes in syn-nodejs-puppeteer-11.0** 
+ Multi-browser support – You can now run Node.js Puppeteer canaries in either Firefox or Chrome
+ Simplified packaging – Package scripts directly under root without using the Node.js/node\$1modules directory structure
+ Screenshot integration – Capture screenshots using native Puppeteer functions to visualize canary script stages. Synthetics automatically associates screenshots with canary steps and uploads them to Amazon S3
+ Enhanced log querying – Query and filter logs through the CloudWatch Insights console. Each log message includes a unique `canaryRunId` for easier searching
+ Configuration file support – Define and update Synthetics settings using a synthetics.json file. This separation of configuration from script logic improves maintenance and reusability
+ Multiple tabs support – Create canaries that open multiple browser tabs and access screenshots from each tab. Build multi-tab and multi-step user workflows in Synthetics
+ Security fixes
+ Visual monitoring bug fixes
+ Added support for structured JSON logging with configurable log levels – Logs are now emitted in JSON format to enable easier parsing and querying in CloudWatch. Log level is configurable (for example, DEBUG, INFO, TRACE) through environment variables allowing users to control verbosity based on their needs
+ Support for ES syntax

### syn-nodejs-puppeteer-10.0


For more information, see the following:
+  [Puppeteer Change log](https://pptr.dev/CHANGELOG) 
+  [Puppeteer API reference](https://github.com/puppeteer/puppeteer/blob/puppeteer-v24.2.0/docs/api/index.md) 

**Major dependencies**:
+ Lambda runtime Node.js 20.x
+ Puppeteer-core version 24.2.0
+ Chromium version 131.0.6778.264

 **Changes in syn-nodejs-puppeteer-10.0** 
+ The bug related to closing the browser that took excessively long is fixed.
+ Supports dry runs for the canary which allows for adhoc executions or performing a safe canary update.

### syn-nodejs-puppeteer-9.1


**Major dependencies**:
+ Lambda runtime Node.js 20.x
+ Puppeteer-core version 22.12.1
+ Chromium version 126.0.6478.126

**Changes in syn-nodejs-puppeteer-9.1** – Bug fixes related to date ranges and pending requests in HAR files are fixed.

### syn-nodejs-puppeteer-9.0


**Major dependencies**:
+ Lambda runtime Node.js 20.x
+ Puppeteer-core version 22.12.1
+ Chromium version 126.0.6478.126

**Changes in syn-nodejs-puppeteer-9.0** – The bug fix to enable visual monitoring capabilities is fixed.

### syn-nodejs-puppeteer-8.0


**Warning**  
Because of a bug, the `syn-nodejs-puppeteer-8.0` runtime doesn't support visual monitoring in canaries. Upgrade to [syn-nodejs-puppeteer-9.0](#CloudWatch_Synthetics_runtimeversion-nodejs-puppeteer-9.0) for the bug fix for visual monitoring.

**Important**  
Lambda Node.js 18 and later runtimes use Amazon SDK for JavaScript V3. If you need to migrate a canary from an earlier runtime, follow the [aws-sdk-js-v3 Migration Workshop](https://github.com/aws-samples/aws-sdk-js-v3-workshop) on GitHub. For more information about Amazon SDK for JavaScript version 3, see [this blog post](https://aws.amazon.com/blogs/developer/modular-aws-sdk-for-javascript-is-now-generally-available/).

**Major dependencies**:
+ Lambda runtime Node.js 20.x
+ Puppeteer-core version 22.10.0
+ Chromium version 125.0.6422.112

**Updates in syn-nodejs-puppeteer-8.0**:
+  **Support for two-factor authentication** 
+ **Bug fixes** related to some service clients losing data in Node.js SDK V3 responses is fixed.

## Deprecated runtime versions for Node.js and Puppeteer


The following runtimes for Node.js and Puppeteer have been deprecated. For information about runtime deprecation dates, see [CloudWatch Synthetics runtime deprecation dates](CloudWatch_Synthetics_Runtime_Support_Policy.md#runtime_deprecation_dates).

### syn-nodejs-puppeteer-7.0


**Major dependencies**:
+ Lambda runtime Node.js 18.x
+ Puppeteer-core version 21.9.0
+ Chromium version 121.0.6167.139

**Code size**:

The size of code and dependencies that you can package into this runtime is 80 MB.

**Updates in syn-nodejs-puppeteer-7.0**:
+ **Updated versions of the bundled libraries in Puppeteer and Chromium**— The Puppeteer and Chromium dependencies are updated to new versions.
**Important**  
Moving from Puppeteer 19.7.0 to Puppeteer 21.9.0 introduces breaking changes regarding testing and filters. For more information, see the **BREAKING CHANGES** sections in [puppeteer: v20.0.0](https://github.com/puppeteer/puppeteer/releases/tag/puppeteer-v20.0.0) and [puppeteer-core: v21.0.0](https://github.com/puppeteer/puppeteer/releases/tag/puppeteer-core-v21.0.0).

 **Recommended upgrade to Amazon SDK v3** 

The Lambda nodejs18.x runtime doesn't support Amazon SDK v2. We strongly recommend that you migrate to Amazon SDK v3.

### syn-nodejs-puppeteer-6.2


**Major dependencies**:
+ Lambda runtime Node.js 18.x
+ Puppeteer-core version 19.7.0
+ Chromium version 111.0.5563.146

**Changes in syn-nodejs-puppeteer-6.2**:
+  **Updated versions of the bundled libraries in Chromium** 
+ **Ephemeral storage monitoring**— This runtime adds ephemeral storage monitoring in customer accounts.
+  **Bug fixes** 

### syn-nodejs-puppeteer-6.1


**Major dependencies**:
+ Lambda runtime Node.js 18.x
+ Puppeteer-core version 19.7.0
+ Chromium version 111.0.5563.146

**Updates in syn-nodejs-puppeteer-6.1**:
+ **Stability improvements**— Added auto-retry logic for handling intermittent Puppeteer launch errors.
+ **Dependency upgrades**— Upgrades for some third-party dependency packages.
+ **Canaries without Amazon S3 permissions**— Bug fixes, such that canaries that don't have any Amazon S3 permissions can still run. These canaries with no Amazon S3 permissions won't be able to upload screenshots or other artifacts to Amazon S3. For more information about permissions for canaries, see [Required roles and permissions for canaries](CloudWatch_Synthetics_Canaries_CanaryPermissions.md).

**Important**  
IMPORTANT: The included Amazon SDK for JavaScript v2 dependency will be removed and updated to use Amazon SDK for JavaScript v3 in a future runtime release. When that happens, you can update your canary code references. Alternatively, you can continue referencing and using the included Amazon SDK for JavaScript v2 dependency by adding it as a dependency to your source code zip file.

### syn-nodejs-puppeteer-6.0


**Major dependencies**:
+ Lambda runtime Node.js 18.x
+ Puppeteer-core version 19.7.0
+ Chromium version 111.0.5563.146

**Updates in syn-nodejs-puppeteer-6.0**:
+ **Dependency upgrade**— The Node.js dependency is upgraded to 18.x.
+ **Intercept mode support**— Puppeteer cooperative intercept mode support was added to the Synthetics canary runtime library.
+ **Tracing behavior change**— Changed default tracing behavior to trace only fetch and xhr requests, and not trace resource requests. You can enable the tracing of resource requests by configuring the `traceResourceRequests` option.
+ **Duration metric refined**— The ` Duration` metric now excludes the operation time the canary uses to upload artifacts, take screenshots, and generate CloudWatch metrics. `Duration` metric values are reported to CloudWatch, and you can also see them in the Synthetics console.
+ **Bug fix**— Clean up core dump generated when Chromium crashes during a canary run.

**Important**  
IMPORTANT: The included Amazon SDK for JavaScript v2 dependency will be removed and updated to use Amazon SDK for JavaScript v3 in a future runtime release. When that happens, you can update your canary code references. Alternatively, you can continue referencing and using the included Amazon SDK for JavaScript v2 dependency by adding it as a dependency to your source code zip file.

### syn-nodejs-puppeteer-5.2


**Major dependencies**:
+ Lambda runtime Node.js 16.x
+ Puppeteer-core version 19.7.0
+ Chromium version 111.0.5563.146

**Updates in syn-nodejs-puppeteer-5.2**:
+  **Updated versions of the bundled libraries in Chromium** 
+  **Bug fixes** 

### syn-nodejs-puppeteer-5.1


**Major dependencies**:
+ Lambda runtime Node.js 16.x
+ Puppeteer-core version 19.7.0
+ Chromium version 111.0.5563.146

**Bug fixes in syn-nodejs-puppeteer-5.1**:
+ **Bug fix**— This runtime fixes a bug in ` syn-nodejs-puppeteer-5.0` where the HAR files created by the canaries were missing request headers.

### syn-nodejs-puppeteer-5.0


**Major dependencies**:
+ Lambda runtime Node.js 16.x
+ Puppeteer-core version 19.7.0
+ Chromium version 111.0.5563.146

**Updates in syn-nodejs-puppeteer-5.0**:
+ **Dependency upgrade**— The Puppeteer-core version is updated to 19.7.0. The Chromium version is upgraded to 111.0.5563.146.

**Important**  
The new Puppeteer-core version is not completely backward-compatible with previous versions of Puppeteer. Some of the changes in this version can cause existing canaries that use deprecated Puppeteer functions to fail. For more information, see the breaking changes in the change logs for Puppeteer-core versions 19.7.0 through 6.0, in [Puppeteer change logs](https://github.com/puppeteer/puppeteer/releases?q=breaking&expanded=true).

### syn-nodejs-puppeteer-4.0


**Major dependencies**:
+ Lambda runtime Node.js 16.x
+ Puppeteer-core version 5.5.0
+ Chromium version 92.0.4512

**Updates in syn-nodejs-puppeteer-4.0**:
+ **Dependency upgrade**— The Node.js dependency is updated to 16.x.

### syn-nodejs-puppeteer-3.9


**Important**  
This runtime version was deprecated on January 8, 2024. For more information, see [Runtime versions support policy](CloudWatch_Synthetics_Runtime_Support_Policy.md).

**Major dependencies**:
+ Lambda runtime Node.js 14.x
+ Puppeteer-core version 5.5.0
+ Chromium version 92.0.4512

**Updates in syn-nodejs-puppeteer-3.9**:
+ **Dependency upgrades**— Upgrades some third-party dependency packages.

### syn-nodejs-puppeteer-3.8


**Important**  
This runtime version was deprecated on January 8, 2024. For more information, see [Runtime versions support policy](CloudWatch_Synthetics_Runtime_Support_Policy.md).

**Major dependencies**:
+ Lambda runtime Node.js 14.x
+ Puppeteer-core version 5.5.0
+ Chromium version 92.0.4512

**Updates in syn-nodejs-puppeteer-3.8**:
+ **Profile cleanup**— Chromium profiles are now cleaned up after each canary run.

**Bug fixes in syn-nodejs-puppeteer-3.8**:
+ **Bug fixes**— Previously, visual monitoring canaries would sometimes stop working properly after a run with no screenshots. This is now fixed.

### syn-nodejs-puppeteer-3.7


**Important**  
This runtime version was deprecated on January 8, 2024. For more information, see [Runtime versions support policy](CloudWatch_Synthetics_Runtime_Support_Policy.md).

**Major dependencies**:
+ Lambda runtime Node.js 14.x
+ Puppeteer-core version 5.5.0
+ Chromium version 92.0.4512

**Updates in syn-nodejs-puppeteer-3.7**:
+ **Logging enhancement**— The canary will upload logs to Amazon S3 even if it times out or crashes.
+ **Lambda layer size reduced**— The size of the Lambda layer used for canaries is reduced by 34%.

**Bug fixes in syn-nodejs-puppeteer-3.7**:
+ **Bug fixes**— Japanese, Simplified Chinese, and Traditional Chinese fonts will render properly.

### syn-nodejs-puppeteer-3.6


**Important**  
This runtime version was deprecated on January 8, 2024. For more information, see [Runtime versions support policy](CloudWatch_Synthetics_Runtime_Support_Policy.md).

**Major dependencies**:
+ Lambda runtime Node.js 14.x
+ Puppeteer-core version 5.5.0
+ Chromium version 92.0.4512

**Updates in syn-nodejs-puppeteer-3.6**:
+ **More precise timestamps**— The start time and stop time of canary runs are now precise to the millisecond.

### syn-nodejs-puppeteer-3.5


**Important**  
This runtime version was deprecated on January 8, 2024. For more information, see [Runtime versions support policy](CloudWatch_Synthetics_Runtime_Support_Policy.md).

**Major dependencies**:
+ Lambda runtime Node.js 14.x
+ Puppeteer-core version 5.5.0
+ Chromium version 92.0.4512

**Updates in syn-nodejs-puppeteer-3.5**:
+ **Updated dependencies**— The only new features in this runtime are the updated dependencies.

### syn-nodejs-puppeteer-3.4


**Important**  
This runtime version was deprecated on November 13, 2022. For more information, see [Runtime versions support policy](CloudWatch_Synthetics_Runtime_Support_Policy.md).

**Major dependencies**:
+ Lambda runtime Node.js 12.x
+ Puppeteer-core version 5.5.0
+ Chromium version 88.0.4298.0

**Updates in syn-nodejs-puppeteer-3.4**:
+ **Custom handler function**— You can now use a custom handler function for your canary scripts. Previous runtimes required the script entry point to include `.handler`. 

  You can also put canary scripts in any folder and pass the folder name as part of the handler. For example, `MyFolder/MyScriptFile.functionname` can be used as an entry point.
+ **Expanded HAR file information**— You can now see bad, pending, and incomplete requests in the HAR files produced by canaries.

### syn-nodejs-puppeteer-3.3


**Important**  
This runtime version was deprecated on November 13, 2022. For more information, see [Runtime versions support policy](CloudWatch_Synthetics_Runtime_Support_Policy.md).

**Major dependencies**:
+ Lambda runtime Node.js 12.x
+ Puppeteer-core version 5.5.0
+ Chromium version 88.0.4298.0

**Updates in syn-nodejs-puppeteer-3.3**:
+ **More options for artifact encryption**— For canaries using this runtime or later, instead of using an Amazon managed key to encrypt artifacts that the canary stores in Amazon S3, you can choose to use an Amazon KMS customer managed key or an Amazon S3-managed key. For more information, see [Encrypting canary artifacts](CloudWatch_Synthetics_artifact_encryption.md). 

### syn-nodejs-puppeteer-3.2


**Important**  
This runtime version was deprecated on November 13, 2022. For more information, see [Runtime versions support policy](CloudWatch_Synthetics_Runtime_Support_Policy.md).

**Major dependencies**:
+ Lambda runtime Node.js 12.x
+ Puppeteer-core version 5.5.0
+ Chromium version 88.0.4298.0

**Updates in syn-nodejs-puppeteer-3.2**:
+ **visual monitoring with screenshots**— Canaries using this runtime or later can compare a screenshot taken during a run with a baseline version of the same screenshot. If the screenshots are more different than a specified percentage threshold, the canary fails. For more information, see [Visual monitoring](CloudWatch_Synthetics_Canaries_Library_Nodejs.md#CloudWatch_Synthetics_Library_SyntheticsLogger_VisualTesting) or [Visual monitoring blueprint](CloudWatch_Synthetics_Canaries_Blueprints.md#CloudWatch_Synthetics_Canaries_Blueprints_VisualTesting). 
+ **New functions regarding sensitive data** You can prevent sensitive data from appearing in canary logs and reports. For more information, see [SyntheticsLogHelper class](CloudWatch_Synthetics_Canaries_Library_Nodejs.md#CloudWatch_Synthetics_Library_SyntheticsLogHelper).
+ **Deprecated function** The ` RequestResponseLogHelper` class is deprecated in favor of other new configuration options. For more information, see [RequestResponseLogHelper class](CloudWatch_Synthetics_Canaries_Library_Nodejs.md#CloudWatch_Synthetics_Library_RequestResponseLogHelper).

### syn-nodejs-puppeteer-3.1


**Important**  
This runtime version was deprecated on November 13, 2022. For more information, see [Runtime versions support policy](CloudWatch_Synthetics_Runtime_Support_Policy.md).

**Major dependencies**:
+ Lambda runtime Node.js 12.x
+ Puppeteer-core version 5.5.0
+ Chromium version 88.0.4298.0

**Updates in syn-nodejs-puppeteer-3.1**:
+ **Ability to configure CloudWatch metrics**— With this runtime, you can disable the metrics that you do not require. Otherwise, canaries publish various CloudWatch metrics for each canary run.
+ **Screenshot linking**— You can link a screenshot to a canary step after the step has completed. To do this, you take the screenshot by using the **takeScreenshot** method, using the name of the step that you want to associate the screenshot with. For example, you might want to perform a step, add a wait time, and then take the screenshot.
+ **Heartbeat monitor blueprint can monitor multiple URLs**— You can use the heartbeat monitoring blueprint in the CloudWatch console to monitor multiple URLs and see the status, duration, associated screenshots, and failure reason for each URL in the step summary of the canary run report.

### syn-nodejs-puppeteer-3.0


**Important**  
This runtime version was deprecated on November 13, 2022. For more information, see [Runtime versions support policy](CloudWatch_Synthetics_Runtime_Support_Policy.md).

**Major dependencies**:
+ Lambda runtime Node.js 12.x
+ Puppeteer-core version 5.5.0
+ Chromium version 88.0.4298.0

**Updates in syn-nodejs-puppeteer-3.0**:
+ **Upgraded dependencies**— This version uses Puppeteer version 5.5.0, Node.js 12.x, and Chromium 88.0.4298.0.
+ **Cross-Region bucket access**— You can now specify an S3 bucket in another Region as the bucket where your canary stores its log files, screenshots, and HAR files.
+ **New functions available**— This version adds library functions to retrieve the canary name and the Synthetics runtime version.

  For more information, see [Synthetics class](CloudWatch_Synthetics_Canaries_Library_Nodejs.md#CloudWatch_Synthetics_Library_Synthetics_Class_all).

### syn-nodejs-2.2


This section contains information about the `syn-nodejs-2.2` runtime version.

**Important**  
This runtime version was deprecated on May 28, 2021. For more information, see [Runtime versions support policy](CloudWatch_Synthetics_Runtime_Support_Policy.md).

**Major dependencies**:
+ Lambda runtime Node.js 10.x
+ Puppeteer-core version 3.3.0
+ Chromium version 83.0.4103.0

**Changes in syn-nodejs-2.2**:
+ **Monitor your canaries as HTTP steps**— You can now test multiple APIs in a single canary. Each API is tested as a separate HTTP step, and CloudWatch Synthetics monitors the status of each step using step metrics and the CloudWatch Synthetics step report. CloudWatch Synthetics creates ` SuccessPercent` and `Duration` metrics for each HTTP step.

  This functionality is implemented by the **executeHttpStep(stepName, requestOptions, callback, stepConfig)** function. For more information, see [executeHttpStep(stepName, requestOptions, [callback], [stepConfig])](CloudWatch_Synthetics_Canaries_Library_Nodejs.md#CloudWatch_Synthetics_Library_executeHttpStep).

  The API canary blueprint is updated to use this new feature.
+ **HTTP request reporting**— You can now view detailed HTTP requests reports which capture details such as request/response headers, response body, status code, error and performance timings, TCP connection time, TLS handshake time, first byte time, and content transfer time. All HTTP requests which use the HTTP/HTTPS module under the hood are captured here. Headers and response body are not captured by default but can be enabled by setting configuration options.
+ **Global and step-level configuration**— You can set CloudWatch Synthetics configurations at the global level, which are applied to all steps of canaries. You can also override these configurations at the step level by passing configuration key/value pairs to enable or disable certain options.

  For more information, see [SyntheticsConfiguration class](CloudWatch_Synthetics_Canaries_Library_Nodejs.md#CloudWatch_Synthetics_Library_SyntheticsConfiguration).
+ **Continue on step failure configuration**— You can choose to continue canary execution when a step fails. For the ` executeHttpStep` function, this is turned on by default. You can set this option once at global level or set it differently per-step. 

### syn-nodejs-2.1


**Important**  
This runtime version was deprecated on May 28, 2021. For more information, see [Runtime versions support policy](CloudWatch_Synthetics_Runtime_Support_Policy.md).

**Major dependencies**:
+ Lambda runtime Node.js 10.x
+ Puppeteer-core version 3.3.0
+ Chromium version 83.0.4103.0

**Updates in syn-nodejs-2.1**:
+ **Configurable screenshot behavior**— Provides the ability to turn off the capturing of screenshots by UI canaries. In canaries that use previous versions of the runtimes, UI canaries always capture screenshots before and after each step. With `syn-nodejs-2.1`, this is configurable. Turning off screenshots can reduce your Amazon S3 storage costs, and can help you comply with HIPAA regulations. For more information, see [SyntheticsConfiguration class](CloudWatch_Synthetics_Canaries_Library_Nodejs.md#CloudWatch_Synthetics_Library_SyntheticsConfiguration).
+ **Customize the Google Chrome launch parameters** You can now configure the arguments used when a canary launches a Google Chrome browser window. For more information, see [launch(options)](CloudWatch_Synthetics_Canaries_Library_Nodejs.md#CloudWatch_Synthetics_Library_LaunchOptions).

There can be a small increase in canary duration when using syn-nodejs-2.0 or later, compared to earlier versions of the canary runtimes.

### syn-nodejs-2.0


**Important**  
This runtime version was deprecated on May 28, 2021. For more information, see [Runtime versions support policy](CloudWatch_Synthetics_Runtime_Support_Policy.md).

**Major dependencies**:
+ Lambda runtime Node.js 10.x
+ Puppeteer-core version 3.3.0
+ Chromium version 83.0.4103.0

**Updates in syn-nodejs-2.0**:
+ **Upgraded dependencies**— This runtime version uses Puppeteer-core version 3.3.0 and Chromium version 83.0.4103.0
+ **Support for X-Ray active tracing.** When a canary has tracing enabled, X-Ray traces are sent for all calls made by the canary that use the browser, the Amazon SDK, or HTTP or HTTPS modules. Canaries with tracing enabled appear on the X-Ray Trace Map, even when they don't send requests to other services or applications that have tracing enabled. For more information, see [Canaries and X-Ray tracing](CloudWatch_Synthetics_Canaries_tracing.md).
+ **Synthetics reporting**— For each canary run, CloudWatch Synthetics creates a report named ` SyntheticsReport-PASSED.json` or ` SyntheticsReport-FAILED.json` which records data such as start time, end time, status, and failures. It also records the PASSED/FAILED status of each step of the canary script, and failures and screenshots captured for each step.
+ **Broken link checker report**— The new version of the broken link checker included in this runtime creates a report that includes the links that were checked, status code, failure reason (if any), and source and destination page screenshots.
+ **New CloudWatch metrics**— Synthetics publishes metrics named `2xx`, `4xx`, `5xx`, and `RequestFailed` in the `CloudWatchSynthetics` namespace. These metrics show the number of 200s, 400s, 500s, and request failures in the canary runs. With this runtime version, these metrics are reported only for UI canaries, and are not reported for API canaries. They are also reported for API canaries starting with runtime version ` syn-nodejs-puppeteeer-2.2`.
+ **Sortable HAR files**— You can now sort your HAR files by status code, request size, and duration.
+ **Metrics timestamp**— CloudWatch metrics are now reported based on the Lambda invocation time instead of the canary run end time.

**Bug fixes in syn-nodejs-2.0**:
+ Fixed the issue of canary artifact upload errors not being reported. Such errors are now surfaced as execution errors.
+ Fixed the issue of redirected requests (3xx) being incorrectly logged as errors.
+ Fixed the issue of screenshots being numbered starting from 0. They should now start with 1.
+ Fixed the issue of screenshots being garbled for Chinese and Japanese fonts.

There can be a small increase in canary duration when using syn-nodejs-2.0 or later, compared to earlier versions of the canary runtimes.

### syn-nodejs-2.0-beta


**Important**  
This runtime version was deprecated on February 8, 2021. For more information, see [Runtime versions support policy](CloudWatch_Synthetics_Runtime_Support_Policy.md).

**Major dependencies**:
+ Lambda runtime Node.js 10.x
+ Puppeteer-core version 3.3.0
+ Chromium version 83.0.4103.0

**Changes in syn-nodejs-2.0-beta**:
+ **Upgraded dependencies**— This runtime version uses Puppeteer-core version 3.3.0 and Chromium version 83.0.4103.0
+ **Synthetics reporting**— For each canary run, CloudWatch Synthetics creates a report named ` SyntheticsReport-PASSED.json` or ` SyntheticsReport-FAILED.json` which records data such as start time, end time, status, and failures. It also records the PASSED/FAILED status of each step of the canary script, and failures and screenshots captured for each step.
+ **Broken link checker report**— The new version of the broken link checker included in this runtime creates a report that includes the links that were checked, status code, failure reason (if any), and source and destination page screenshots.
+ **New CloudWatch metrics**— Synthetics publishes metrics named `2xx`, `4xx`, `5xx`, and `RequestFailed` in the `CloudWatchSynthetics` namespace. These metrics show the number of 200s, 400s, 500s, and request failures in the canary runs. These metrics are reported only for UI canaries, and are not reported for API canaries.
+ **Sortable HAR files**— You can now sort your HAR files by status code, request size, and duration.
+ **Metrics timestamp**— CloudWatch metrics are now reported based on the Lambda invocation time instead of the canary run end time.

**Bug fixes in syn-nodejs-2.0-beta**:
+ Fixed the issue of canary artifact upload errors not being reported. Such errors are now surfaced as execution errors.
+ Fixed the issue of redirected requests (3xx) being incorrectly logged as errors.
+ Fixed the issue of screenshots being numbered starting from 0. They should now start with 1.
+ Fixed the issue of screenshots being garbled for Chinese and Japanese fonts.

### syn-1.0


The first Synthetics runtime version is `syn-1.0`.

**Major dependencies**:
+ Lambda runtime Node.js 10.x
+ Puppeteer-core version 1.14.0
+ The Chromium version that matches Puppeteer-core 1.14.0

# Runtime versions using Python and Selenium Webdriver


The following sections contain information about the CloudWatch Synthetics runtime versions for Python and Selenium Webdriver. Selenium is an open-source browser automation tool. For more information about Selenium, see [ www.selenium.dev/](https://www.selenium.dev)

For features and methods supported by Synthetics runtime on Selenium framework, see [Python and Selenium library classes and functions that apply to UI canaries only ](https://docs.amazonaws.cn/AmazonCloudWatch/latest/monitoring/CloudWatch_Synthetics_Canaries_Library_Python.html#CloudWatch_Synthetics_Library_Python_UIcanaries) and [Selenium API reference](https://www.selenium.dev/selenium/docs/api/py/api.html).

The naming convention for these runtime versions is `syn-language -framework-majorversion. minorversion`.

## syn-python-selenium-10.0


Version 10.0 is the newest CloudWatch Synthetics runtime for Python and Selenium.

**Major dependencies**:
+ Python 3.11
+ Selenium 4.32.0
+ Chromium version 145.0.7632.77

**Changes in syn-python-selenium-10.0 ** 
+ Applied security patches and updated browser versions.

For more information, see the following:
+  [Selenium Change log](https://www.selenium.dev/blog/2025/selenium-4-32-released) 
+  [Selenium documentation](https://www.selenium.dev/selenium/docs/api/py/api.html) 

## Previous runtime versions for Python and Selenium


The following earlier runtime versions for Python and Selenium are still supported. 

### syn-python-selenium-9.0


**Major dependencies**:
+ Python 3.11
+ Selenium 4.32.0
+ Chromium version 143.0.7499.169

**Changes in syn-python-selenium-9.0 ** 
+ Applied security patches and updated browser versions.

For more information, see the following:
+  [Selenium Change log](https://www.selenium.dev/blog/2025/selenium-4-32-released) 
+  [Selenium documentation](https://www.selenium.dev/selenium/docs/api/py/api.html) 

### syn-python-selenium-8.0


Version 8.0 is the newest CloudWatch Synthetics runtime for Python and Selenium.

**Major dependencies**:
+ Python 3.11
+ Selenium 4.32.0
+ Chromium version 142.0.7444.175

**Changes in syn-python-selenium-8.0 ** 
+ Applied security patches and updated Selenium and browser versions.
+ Modified failed HAR network request log level from ERROR to INFO.

For more information, see the following:
+  [Selenium Change log](https://www.selenium.dev/blog/2025/selenium-4-32-released) 
+  [Selenium documentation](https://www.selenium.dev/selenium/docs/api/py/api.html) 

### syn-python-selenium-7.0


**Major dependencies**:
+ Python 3.11
+ Selenium 4.32.0
+ Chromium version 138.0.7204.168

 **Changes in syn-python-selenium-7.0 ** 
+ Applied security patches and updated Selenium and browser versions.

For more information, see the following:
+  [Selenium Change log](https://www.selenium.dev/blog/2025/selenium-4-32-released) 
+  [Selenium documentation](https://www.selenium.dev/selenium/docs/api/py/api.html) 

### syn-python-selenium-6.0


**Major dependencies**:
+ Python 3.11
+ Selenium 4.21.0
+ Chromium version 131.0.6778.264

 **Changes in syn-python-selenium-6.0** 
+ Upgrade from Python 3.9 to Python 3.11.

For more information, see the following:
+  [Selenium Change log](https://www.selenium.dev/blog/2024/selenium-4-21-released/) 
+  [Selenium documentation](https://www.selenium.dev/selenium/docs/api/py/api.html) 

### syn-python-selenium-5.1


**Major dependencies**:
+ Python 3.9
+ Selenium 4.21.0
+ Chromium version 131.0.6778.264

 **Changes in syn-python-selenium-5.1** 
+ Minor updates on metric emission.
+ Supports dry runs for the canary which allows for adhoc executions or performing a safe canary update.

### syn-python-selenium-5.0


**Major dependencies**:
+ Python 3.9
+ Selenium 4.21.0
+ Chromium version 131.0.6778.264

**Changes in syn-python-selenium-5.0**:
+ Automatic retry if the browser fails to launch.

### syn-python-selenium-4.1


**Major dependencies**:
+ Python 3.9
+ Selenium 4.15.1
+ Chromium version 126.0.6478.126

**Changes in syn-python-selenium-4.1**:
+ **Addresses security vulnerability**– This runtime has an update to address the [CVE-2024-39689](https://nvd.nist.gov/vuln/detail/CVE-2024-39689) vulnerability.

### syn-python-selenium-4.0


**Major dependencies**:
+ Python 3.9
+ Selenium 4.15.1
+ Chromium version 126.0.6478.126

**Changes in syn-python-selenium-4.0**:
+ **Bug fixes** for errors in HAR parser logging.

## Deprecated runtime versions for Python and Selenium


The following earlier runtime versions for Python and Selenium have been deprecated. For information about runtime deprecation dates, see [CloudWatch Synthetics runtime deprecation dates](CloudWatch_Synthetics_Runtime_Support_Policy.md#runtime_deprecation_dates).

### syn-python-selenium-3.0


**Major dependencies**:
+ Python 3.8
+ Selenium 4.15.1
+ Chromium version 121.0.6167.139

**Changes in syn-python-selenium-3.0**:
+ **Updated versions of the bundled libraries in Chromium**— The Chromium dependency is updated to a new version.

### syn-python-selenium-2.1


**Major dependencies**:
+ Python 3.8
+ Selenium 4.15.1
+ Chromium version 111.0.5563.146

**Changes in syn-python-selenium-2.1**:
+ **Updated versions of the bundled libraries in Chromium**— The Chromium and Selenium dependencies are updated to new versions.

### syn-python-selenium-2.0


**Major dependencies**:
+ Python 3.8
+ Selenium 4.10.0
+ Chromium version 111.0.5563.146

**Changes in syn-python-selenium-2.0**:
+ **Updated dependencies**— The Chromium and Selenium dependencies are updated to new versions.

**Bug fixes in syn-python-selenium-2.0**:
+ **Timestamp added**— A timestamp has been added to canary logs.
+ **Session re-use**— A bug was fixed so that canaries are now prevented from reusing the session from their previous canary run.

### syn-python-selenium-1.3


**Major dependencies**:
+ Python 3.8
+ Selenium 3.141.0
+ Chromium version 92.0.4512.0

**Changes in syn-python-selenium-1.3**:
+ **More precise timestamps**— The start time and stop time of canary runs are now precise to the millisecond.

### syn-python-selenium-1.2


**Major dependencies**:
+ Python 3.8
+ Selenium 3.141.0
+ Chromium version 92.0.4512.0
+ **Updated dependencies**— The only new features in this runtime are the updated dependencies.

### syn-python-selenium-1.1


**Major dependencies**:
+ Python 3.8
+ Selenium 3.141.0
+ Chromium version 83.0.4103.0

**Features**:
+ **Custom handler function**— You can now use a custom handler function for your canary scripts. Previous runtimes required the script entry point to include `.handler`. 

  You can also put canary scripts in any folder and pass the folder name as part of the handler. For example, `MyFolder/MyScriptFile.functionname` can be used as an entry point.
+ **Configuration options for adding metrics and step failure configurations**— These options were already available in runtimes for Node.js canaries. For more information, see [SyntheticsConfiguration class](CloudWatch_Synthetics_Canaries_Library_Python.md#CloudWatch_Synthetics_Library_SyntheticsConfiguration_Python) .
+ **Custom arguments in Chrome **— You can now open a browser in incognito mode or pass in proxy server configuration. For more information, see [Chrome()](CloudWatch_Synthetics_Canaries_Library_Python.md#CloudWatch_Synthetics_Library_Python_Chrome).
+ **Cross-Region artifact buckets**— A canary can store its artifacts in an Amazon S3 bucket in a different Region.
+ **Bug fixes, including a fix for the `index.py` issue**— With previous runtimes, a canary file named ` index.py` caused exceptions because it conflicted with the name of the library file. This issue is now fixed.

### syn-python-selenium-1.0


**Major dependencies**:
+ Python 3.8
+ Selenium 3.141.0
+ Chromium version 83.0.4103.0

**Features**:
+ **Selenium support**— You can write canary scripts using the Selenium test framework. You can bring your Selenium scripts from elsewhere into CloudWatch Synthetics with minimal changes, and they will work with Amazon services.

# Runtime versions using Node.js


The following section contains information about the CloudWatch Synthetics runtime versions for Node.js. This runtime does not have any browser or framework included.

The naming convention for these runtime versions is `syn-language -majorversion.minorversion`.

## syn-nodejs-4.1


**Important**  
Starting Synthetics `syn-nodejs-3.1` and later, Synthetics runtime uses the new namespace. Please migrate the canary script to use the new namespace. Legacy namespace will be deprecated in a future release.  
@amzn/synthetics-core → @aws/synthetics-core

**Major dependencies**:
+ Amazon Lambda runtime Node.js 22.x

 **Changes in syn-nodejs-4.1** 
+ Upgrade `fast-xml-parser` to 5.5.7 to address the following CVEs:
  + CVE-2026-25128
  + CVE-2026-25896
  + CVE-2026-26278
  + CVE-2026-27942
  + CVE-2026-33036

## Previous runtime versions for Node.js


The following earlier runtime versions for Node.js are still supported. 

### syn-nodejs-4.0


**Major dependencies**:
+ Amazon Lambda runtime Node.js 22.x

 **Changes in syn-nodejs-4.0** 
+ Applied security patches. 

### syn-nodejs-3.1


**Important**  
Starting Synthetics `syn-nodejs-3.1` and later, Synthetics runtime uses the new namespace. Please migrate the canary script to use the new namespace. Legacy namespace will be deprecated in a future release.  
@amzn/synthetics-core → @aws/synthetics-core

**Major dependencies**:
+ Amazon Lambda runtime Node.js 20.x

 **Changes in syn-nodejs-3.1** 
+ Synthetics runtime namespace migration. 
+ Type definition is available in [npm Registry](https://www.npmjs.com/package/@aws/synthetics-core). Please ensure the type definition package version matches your canary's runtime version.

### syn-nodejs-3.0


**Major dependencies**:
+ Amazon Lambda runtime Node.js 20.x

 **Changes in syn-nodejs-3.0** 
+ Support for multi checks blueprint. 

# Runtime versions support policy


Synthetics runtime versions are subject to maintenance and security updates. When any component of a runtime version is no longer supported, that Synthetics runtime version is deprecated.

You can't create canaries using deprecated runtime versions. Canaries that use deprecated runtimes continue to run. You can stop, start, and delete these canaries. You can update an existing canary that uses a deprecated runtime version by updating the canary to use a supported runtime version.

CloudWatch Synthetics notifies you by email if you have canaries that use runtimes that are scheduled to be deprecated in the next 60 days. We recommend that you migrate your canaries to a supported runtime version to benefit from the new functionality, security, and performance enhancements that are included in more recent releases. 

## CloudWatch Synthetics runtime deprecation dates


The following table lists the date of deprecation of each deprecated CloudWatch Synthetics runtime.


| Runtime Version | Deprecation date | 
| --- | --- | 
|   `syn-python-selenium-5.1`   |  February 3, 2026  | 
|   `syn-python-selenium-5.0`   |  February 3, 2026  | 
|   `syn-python-selenium-4.1`   |  February 3, 2026  | 
|   `syn-python-selenium-4.0`   |  February 3, 2026  | 
|   `syn-nodejs-puppeteer-7.0`   |  January 22, 2026  | 
|   `syn-nodejs-puppeteer-6.2`   |  January 22, 2026  | 
|   `syn-nodejs-puppeteer-5.2`   |  January 22, 2026  | 
|   `syn-python-selenium-3.0`   |  January 22, 2026  | 
|   `syn-python-selenium-2.1`   |  January 22, 2026  | 
|   `syn-nodejs-puppeteer-6.1`   |  March 8, 2024  | 
|   `syn-nodejs-puppeteer-6.0`   |  March 8, 2024  | 
|   `syn-nodejs-puppeteer-5.1`   |  March 8, 2024  | 
|   `syn-nodejs-puppeteer-5.0`   |  March 8, 2024  | 
|   `syn-nodejs-puppeteer-4.0`   |  March 8, 2024  | 
|   `syn-nodejs-puppeteer-3.9`   |  January 8, 2024  | 
|   `syn-nodejs-puppeteer-3.8`   |  January 8, 2024  | 
|   `syn-python-selenium-2.0`   |  March 8, 2024  | 
|   `syn-python-selenium-1.3`   |  March 8, 2024  | 
|   `syn-python-selenium-1.2`   |  March 8, 2024  | 
|   `syn-python-selenium-1.1`   |  March 8, 2024  | 
|   `syn-python-selenium-1.0`   |  March 8, 2024  | 
|   `syn-nodejs-puppeteer-3.7`   |  January 8, 2024  | 
|   `syn-nodejs-puppeteer-3.6`   |  January 8, 2024  | 
|   `syn-nodejs-puppeteer-3.5`   |  January 8, 2024  | 
|   `syn-nodejs-puppeteer-3.4`   |  November 13, 2022  | 
|   `syn-nodejs-puppeteer-3.3`   |  November 13, 2022  | 
|   `syn-nodejs-puppeteer-3.2`   |  November 13, 2022  | 
|   `syn-nodejs-puppeteer-3.1`   |  November 13, 2022  | 
|   `syn-nodejs-puppeteer-3.0`   |  November 13, 2022  | 
|   `syn-nodejs-2.2`   |  May 28, 2021  | 
|   `syn-nodejs-2.1`   |  May 28, 2021  | 
|   `syn-nodejs-2.0`   |  May 28, 2021  | 
|   `syn-nodejs-2.0-beta`   |  February 8, 2021  | 
|   `syn-1.0`   |  May 28, 2021  | 

# Runtime versions update


You can update a canary’s runtime version by using the CloudWatch console, Amazon CloudFormation, the Amazon CLI or the Amazon SDK. When you use the CloudWatch console, you can update up to five canaries at once by selecting them in the canary list page and then choosing **Actions** , **Update Runtime**.

You can verify the update by testing it first before committing the runtime update. When updating the runtime versions, choose the **Start Dry Run** or **Validate and save later** options in the CloudWatch console to create a dry run of the original canary along with any changes you made to the configuration. The dry run will update and execute the canary to validate whether the runtime update is safe for the canary. Once you have verified your canary with the new runtime version, you can update the runtime version of your canary. For more information, see [Performing safe canary updates](performing-safe-canary-upgrades.md).

Alternatively, you can verify the update by first cloning the canary using the CloudWatch console and updating the runtime version. This creates another canary which is a clone of your original canary. Once you have verified your canary with the new runtime version, you can update the runtime version of your original canary and delete the clone canary.

 You can also update multiple canaries using an upgrade script. For more information, see [Canary runtime upgrade script](#CloudWatch_Synthetics_Canaries_upgrade_script).

If you upgrade a canary and it fails, see [Troubleshooting a failed canary](CloudWatch_Synthetics_Canaries_Troubleshoot.md).

## Canary runtime upgrade script


To upgrade a canary script to a supported runtime version, use the following script.

```
const Amazon = require('aws-sdk');

// You need to configure your Amazon credentials and Region.
//   https://docs.aws.amazon.com/sdk-for-javascript/v3/developer-guide/setting-credentials-node.html
//   https://docs.aws.amazon.com/sdk-for-javascript/v3/developer-guide/setting-region.html

const synthetics = new AWS.Synthetics();

const DEFAULT_OPTIONS = {
  /**
   * The number of canaries to upgrade during a single run of this script.
   */
  count: 10,
  /**
   * No canaries are upgraded unless force is specified.
   */
  force: false
};

/**
 * The number of milliseconds to sleep between GetCanary calls when
 * verifying that an update succeeded.
 */
const SLEEP_TIME = 5000;

(async () => {
  try {
    const options = getOptions();

    const versions = await getRuntimeVersions();
    const canaries = await getAllCanaries();
    const upgrades = canaries
      .filter(canary => !versions.isLatestVersion(canary.RuntimeVersion))
      .map(canary => {
        return {
          Name: canary.Name,
          FromVersion: canary.RuntimeVersion,
          ToVersion: versions.getLatestVersion(canary.RuntimeVersion)
        };
      });

    if (options.force) {
      const promises = [];

      for (const upgrade of upgrades.slice(0, options.count)) {
        const promise = upgradeCanary(upgrade);
        promises.push(promise);
        // Sleep for 100 milliseconds to avoid throttling.
        await usleep(100);
      }

      const succeeded = [];
      const failed = [];
      for (let i = 0; i < upgrades.slice(0, options.count).length; i++) {
        const upgrade = upgrades[i];
        const promise = promises[i];
        try {
          await promise;
          console.log(`The update of ${upgrade.Name} succeeded.`);
          succeeded.push(upgrade.Name);
        } catch (e) {
          console.log(`The update of ${upgrade.Name} failed with error: ${e}`);
          failed.push({
            Name: upgrade.Name,
            Reason: e
          });
        }
      }

      if (succeeded.length) {
        console.group('The following canaries were upgraded successfully.');
        for (const name of succeeded) {
          console.log(name);
        }
        console.groupEnd()
      } else {
        console.log('No canaries were upgraded successfully.');
      }

      if (failed.length) {
        console.group('The following canaries were not upgraded successfully.');
        for (const failure of failed) {
          console.log('\x1b[31m', `${failure.Name}: ${failure.Reason}`, '\x1b[0m');
        }
        console.groupEnd();
      }
    } else {
      console.log('Run with --force [--count <count>] to perform the first <count> upgrades shown. The default value of <count> is 10.')
      console.table(upgrades);
    }
  } catch (e) {
    console.error(e);
  }
})();

function getOptions() {
  const force = getFlag('--force', DEFAULT_OPTIONS.force);
  const count = getOption('--count', DEFAULT_OPTIONS.count);
  return { force, count };

  function getFlag(key, defaultValue) {
    return process.argv.includes(key) || defaultValue;
  }
  function getOption(key, defaultValue) {
    const index = process.argv.indexOf(key);
    if (index < 0) {
      return defaultValue;
    }
    const value = process.argv[index + 1];
    if (typeof value === 'undefined' || value.startsWith('-')) {
      throw `The ${key} option requires a value.`;
    }
    return value;
  }
}

function getAllCanaries() {
  return new Promise((resolve, reject) => {
    const canaries = [];

    synthetics.describeCanaries().eachPage((err, data) => {
      if (err) {
        reject(err);
      } else {
        if (data === null) {
          resolve(canaries);
        } else {
          canaries.push(...data.Canaries);
        }
      }
    });
  });
}

function getRuntimeVersions() {
  return new Promise((resolve, reject) => {
    const jsVersions = [];
    const pythonVersions = [];
    synthetics.describeRuntimeVersions().eachPage((err, data) => {
      if (err) {
        reject(err);
      } else {
        if (data === null) {
          jsVersions.sort((a, b) => a.ReleaseDate - b.ReleaseDate);
          pythonVersions.sort((a, b) => a.ReleaseDate - b.ReleaseDate);
          resolve({
            isLatestVersion(version) {
              const latest = this.getLatestVersion(version);
              return latest === version;
            },
            getLatestVersion(version) {
              if (jsVersions.some(v => v.VersionName === version)) {
                return jsVersions[jsVersions.length - 1].VersionName;
              } else if (pythonVersions.some(v => v.VersionName === version)) {
                return pythonVersions[pythonVersions.length - 1].VersionName;
              } else {
                throw Error(`Unknown version ${version}`);
              }
            }
          });
        } else {
          for (const version of data.RuntimeVersions) {
            if (version.VersionName === 'syn-1.0') {
              jsVersions.push(version);
            } else if (version.VersionName.startsWith('syn-nodejs-2.')) {
              jsVersions.push(version);
            } else if (version.VersionName.startsWith('syn-nodejs-puppeteer-')) {
              jsVersions.push(version);
            } else if (version.VersionName.startsWith('syn-python-selenium-')) {
              pythonVersions.push(version);
            } else {
              throw Error(`Unknown version ${version.VersionName}`);
            }
          }
        }
      }
    });
  });
}

async function upgradeCanary(upgrade) {
  console.log(`Upgrading canary ${upgrade.Name} from ${upgrade.FromVersion} to ${upgrade.ToVersion}`);
  await synthetics.updateCanary({ Name: upgrade.Name, RuntimeVersion: upgrade.ToVersion }).promise();
  while (true) {
    await usleep(SLEEP_TIME);
    console.log(`Getting the state of canary ${upgrade.Name}`);
    const response = await synthetics.getCanary({ Name: upgrade.Name }).promise();
    const state = response.Canary.Status.State;
    console.log(`The state of canary ${upgrade.Name} is ${state}`);
    if (state === 'ERROR' || response.Canary.Status.StateReason) {
      throw response.Canary.Status.StateReason;
    }
    if (state !== 'UPDATING') {
      return;
    }
  }
}

function usleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}
```