npm / sst
sst
What changed in sst 4, from its official release notes, upgrade guides and advisories. Sources checked 2026-11-15.
3 breaking1 deprecations10 new APIs and options2 performance1 behavior and defaults2 tooling16 fixes and other
See which of these apply to your code, ranked, in your agent:
npx @unstale/cli initsst 435 changes
Breaking changes 3
FunctionEnvironmentUpdate runs again when Lambda changes.
The AWS SDK client now uses supplied credentials.
Running sst remove removes the state and encryption key.
Deprecations 1
The Vector component is deprecated.
New APIs and options 10
Adds an option to prevent big state buckets.
Adds support for configuring a custom MAIL FROM domain for SES.
Cloudflare components can now override accountId.
A Durable Objects component was added.
Adds a Cloudflare RateLimit component.
Adds an enabled option to bus subscribers.
Adds support for Cloudflare domain redirects and aliases.
Adds support for Hyperdrive.get.
ApiGateway routes can now be named via the name argument.
Adds a Cloudflare Workflow component.
Performance 2
Precompiles Python bytecode to reduce Lambda cold starts.
SDK Resource loading is now lazy.
Behavior and default changes 1
AWS state files are compressed when uploaded to S3.
Tooling 2
Can now run before the first deploy.
Can now run before the first deploy.
Fixes and other changes 16
Guards live function descriptions.
Fixes duplicate CloudWatch role URNs on fresh accounts.
Fixes
sst addso it no longer requires Prettier or other dependencies.Limits the name length of CloudFront Functions used in domain redirects.
A race condition in the watcher was fixed.
Prevents a module from being ignored in the Python SDK.
Prevents a module from being ignored in the Python SDK.
A race condition in the watcher is fixed.
The Python SDK is published to PyPI, making it available through that package index.
The Cloudflare provider was updated.
Python support is improved.
Fixed debugging in JetBrains editors when using sst dev.
Fixes resource links not being found on Windows because of upper casing.
Fixed config decoding when VS Code auto attach is enabled.
Fixes SSR site CloudFront invalidation for server-only changes.
Fixes passing an empty rangeKey to Pulumi.