FsCDK lets you describe AWS infrastructure with a small, expressive F# DSL built on top of the AWS Cloud Development Kit (CDK). If you like computation expressions, immutability, and readable diffs, you’ll feel right at home.

This page gives you a quick, human-sized tour. No buzzwords, just a couple of realistic stacks you can read end-to-end.

What you’ll see below: - Define per-environment settings once and reuse them. - Declare DynamoDB tables, Lambdas, queues and topics with intent, not boilerplate. - Wire resources together (grants and subscriptions) without hunting for ARNs.

#r "../src/bin/Release/net8.0/publish/Amazon.JSII.Runtime.dll"
#r "../src/bin/Release/net8.0/publish/Constructs.dll"
#r "../src/bin/Release/net8.0/publish/Amazon.CDK.Lib.dll"
#r "../src/bin/Release/net8.0/publish/System.Text.Json.dll"
#r "../src/bin/Release/net8.0/publish/FsCDK.dll"

open FsCDK
open Amazon.CDK
open Amazon.CDK.AWS.DynamoDB
open Amazon.CDK.AWS.Lambda

// 1) Environments
let devEnv =
  environment {
    account "123456789012"
    region "us-east-1"
  }

let prodEnv =
  environment {
    account "098765432109"
    region "us-east-1"
  }

// 2) A Dev stack you can actually work with
let devStack =
  stack "Dev" {
    // Attach StackProps implicitly via nested builder
    stackProps {
      env devEnv
      description "Developer stack for feature work"
      tags [ "service", "users"; "env", "dev" ]
    }

    // resources
    table "users" {
      partitionKey "id" AttributeType.STRING
      billingMode BillingMode.PAY_PER_REQUEST
      removalPolicy RemovalPolicy.DESTROY // fine for dev
    }

    lambda "users-api-dev" {
      handler "Users::Handler::FunctionHandler"
      runtime Runtime.DOTNET_8
      code "./examples/lambdas/users" // any folder with your code bundle
      memory 512
      timeout 10.0
      description "CRUD over the users table"
    }

    queue "users-dlq" {
      messageRetention (7.0 * 24.0 * 3600.0) // 7 days
    }

    queue "users-queue" {
      deadLetterQueue "users-dlq" 5
      visibilityTimeout 30.0
    }

    topic "user-events" { displayName "User events" }

    // wiring
    subscription {
      topic "user-events"
      queue "users-queue"
    }

    grant {
      table "users"
      lambda "users-api-dev"
      readWriteAccess
    }
  }

// 3) A production-leaning stack
let prodStack =
  stack "Prod" {
    stackProps {
      env prodEnv
      stackName "users-prod"
      terminationProtection true
      tags [ "service", "users"; "env", "prod" ]
    }

    table "users" {
      partitionKey "id" AttributeType.STRING
      billingMode BillingMode.PAY_PER_REQUEST
      removalPolicy RemovalPolicy.RETAIN // keep data safe
      pointInTimeRecovery true
    }

    lambda "users-api" {
      handler "Users::Handler::FunctionHandler"
      runtime Runtime.DOTNET_8
      code "./examples/lambdas/users"
      memory 1024
      timeout 15.0
      description "CRUD over the users table"
    }

    grant {
      table "users"
      lambda "users-api"
      readWriteAccess
    }
  }

// 4) Build an in-memory CDK app (no deploy here). We create stacks into an App
app {
  // Build both stacks into the same app
  devStack
  prodStack
}