Function

Reference doc for the sst.aws.Function component.

The Function component lets you add serverless functions to your app. It uses AWS Lambda.

Constructor

Tab Title

sst.config.ts

new sst.aws.Function("MyFunction", {
  handler: "src/lambda.handler"
});

Tab Title

sst.config.ts

new sst.aws.Function("MyFunction", {
  runtime: "python3.11",
  handler: "functions/src/functions/api.handler"
});

You need uv installed and your handler in a uv workspace.

Tab Title

sst.config.ts

new sst.aws.Function("MyFunction", {
  runtime: "go",
  handler: "./src"
});

Tab Title

sst.config.ts

new sst.aws.Function("MyFunction", {
  runtime: "rust",
  handler: "./crates/api/"
});

Parameters

handler

handler · string · required

Path to the handler for the function.

• For Node.js: {path}/{file}.{method} format
• For Python: {path}/{file}.{method} format
• For Go: {path} to the Go module
• For Rust: {path} to the Rust crate

{
  handler: "packages/functions/src/main.handler"
}

runtime

runtime · string · default: "nodejs24.x"

The language runtime for the function.

{
  runtime: "nodejs24.x"
}

Supported values: "nodejs18.x", "nodejs20.x", "nodejs22.x", "nodejs24.x", "go", "rust", "provided.al2", "provided.al2023", "python3.9", "python3.10", "python3.11", "python3.12", "python3.13"

timeout

timeout · duration · default: "20 seconds"

The maximum amount of time the function can run. Between 1 second and 900 seconds (15 minutes).

{
  timeout: "900 seconds"
}

If a function is connected to API Gateway, it will time out after 30 seconds regardless of this setting.

memory

memory · string · default: "1024 MB"

The amount of memory allocated for the function. Between 128 MB and 10240 MB in 1 MB increments.

{
  memory: "2048 MB"
}

While less memory is cheaper, larger functions can process faster and might be more cost effective.

link

link · array

Link resources to your function. This will:

1. Grant permissions to access the resources
2. Allow you to access them in your function using the SDK

{
  link: [bucket, stripeKey]
}

environment

environment · Record<string, string>

Key-value pairs of Lambda environment variables.

{
  environment: {
    DEBUG: "true"
  }
}

The total size of environment variables cannot exceed 4 KB.

permissions

permissions · array

Permissions to access other resources. These are added to the function’s IAM role.

{
  permissions: [
    {
      actions: ["s3:GetObject", "s3:PutObject"],
      resources: ["arn:aws:s3:::my-bucket/*"]
    }
  ]
}

If you link the function to a resource, the permissions to access it are automatically added.

url

url · boolean | object · default: "false"

Enable Lambda function URLs.

{
  url: true
}

Configure the authorization and CORS settings:

{
  url: {
    authorization: "iam",
    cors: {
      allowOrigins: ["https://example.com"]
    }
  }
}

vpc

vpc · Vpc | object

Connect the function to private subnets in a VPC.

{
  vpc: myVpc
}

Where myVpc is:

const myVpc = new sst.aws.Vpc("MyVpc");

Properties

name

arn

url

nodes

SDK

When you link a Function to another resource, you can access it in your function code using the SDK.

src/lambda.ts

import { Resource } from "sst";

console.log(Resource.MyFunction.name);

Examples

Set additional config

sst.config.ts

new sst.aws.Function("MyFunction", {
  handler: "src/lambda.handler",
  timeout: "3 minutes",
  memory: "2048 MB"
});

Link resources

Link resources to the function:

sst.config.ts

const bucket = new sst.aws.Bucket("MyBucket");

new sst.aws.Function("MyFunction", {
  handler: "src/lambda.handler",
  link: [bucket]
});

Access linked resources in your function:

src/lambda.ts

import { Resource } from "sst";

console.log(Resource.MyBucket.name);

Enable function URLs

sst.config.ts

new sst.aws.Function("MyFunction", {
  handler: "src/lambda.handler",
  url: true
});

Customize bundling

sst.config.ts

new sst.aws.Function("MyFunction", {
  handler: "src/lambda.handler",
  nodejs: {
    install: ["pg"]
  }
});