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Scopes

Scopes provide hierarchical organization and isolation for your infrastructure. They enable you to group related resources, manage different environments (dev, staging, prod), and control resource lifecycle at multiple levels.

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What is a Scope?

A scope is a container for resources that provides:
  • Namespacing: Unique resource identification within a scope
  • State isolation: Each scope maintains its own state
  • Hierarchical organization: Scopes can contain child scopes
  • Environment separation: Different stages (dev, prod) are separate scopes
  • Credential management: Scopes can override provider credentials
Every Alchemy application has at least two scopes: the root scope (app name) and a stage scope (e.g., “dev”, “prod”).

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Scope Hierarchy

Alchemy applications have a built-in scope hierarchy: 
my-app (root scope)
└── dev (stage scope)
    ├── api (resource)
    ├── database (resource)
    └── storage (child scope)
        └── images (resource)
The fully qualified name (FQN) reflects this hierarchy: 
my-app/dev/api
my-app/dev/storage/images

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Creating Scopes

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Application Scope

Create the root application scope with alchemy(): 
import { alchemy } from "alchemy";

const app = await alchemy("my-app");

// Resources created here are in the "my-app/dev" scope
const worker = await Worker("api", {
  entrypoint: "./src/api.ts"
});

await app.finalize();
The stage scope (“dev”) is automatically created based on the --stage flag or ALCHEMY_STAGE environment variable.

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Child Scopes

Create child scopes with alchemy.run(): 
import { alchemy } from "alchemy";

const app = await alchemy("my-app");

await alchemy.run("storage", async (scope) => {
  // Resources here are in "my-app/dev/storage"
  
  const imageBucket = await R2Bucket("images", {
    name: "user-images"
  });
  
  const documentBucket = await R2Bucket("documents", {
    name: "user-documents"
  });
});

await app.finalize();

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Scope Properties

Scopes provide access to configuration and metadata: 
const app = await alchemy("my-app", {
  stage: "prod",
  password: process.env.ALCHEMY_PASSWORD
});

await alchemy.run("database", async (scope) => {
  console.log(scope.appName);    // "my-app"
  console.log(scope.stage);      // "prod"
  console.log(scope.name);       // "database"
  console.log(scope.scopeName);  // "database"
  console.log(scope.chain);      // ["my-app", "prod", "database"]
  console.log(scope.local);      // false (true if --local flag)
  console.log(scope.watch);      // false (true if --watch flag)
  console.log(scope.phase);      // "up" (or "destroy", "read")
});

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Scope Options

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Stage Configuration

Specify which environment to deploy to: 
# Deploy to production
bun ./alchemy.run.ts --stage prod

# Deploy to development (default)
bun ./alchemy.run.ts --stage dev
Or programmatically: 
const app = await alchemy("my-app", {
  stage: "prod"
});
Different stages maintain completely separate state. Resources in “dev” are independent from resources in “prod”.

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Deployment Phases

Scopes operate in different phases:
PhaseDescriptionTrigger
"up"Create or update resourcesDefault behavior
"destroy"Delete all resources--destroy flag
"read"Read-only, no changes--read flag or --app for non-selected apps
const app = await alchemy("my-app");

await alchemy.run("api", async (scope) => {
  if (scope.phase === "destroy") {
    console.log("Cleaning up resources...");
  }
  
  // Resources automatically respect the phase
  const worker = await Worker("api", {
    entrypoint: "./src/api.ts"
  });
});

await app.finalize();

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Local Development

Enable local simulation mode: 
bun ./alchemy.run.ts --local

const app = await alchemy("my-app", {
  local: true
});

await alchemy.run("api", async (scope) => {
  console.log(scope.local); // true
  
  // Resources can provide local alternatives
  const worker = await Worker("api", {
    entrypoint: "./src/api.ts"
  });
  // Returns local worker URL instead of deployed URL
});
Local mode allows you to develop and test infrastructure code without deploying to the cloud.

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Watch Mode

Automatically redeploy on file changes: 
bun --watch ./alchemy.run.ts
Resources can detect watch mode: 
await alchemy.run("api", async (scope) => {
  if (scope.watch) {
    console.log("Watch mode enabled - auto-redeploying on changes");
  }
});

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Scope State Management

Scopes can store and retrieve custom data: 
await alchemy.run("cache", async (scope) => {
  // Store data in scope state
  await scope.set("lastDeployment", new Date().toISOString());
  
  // Retrieve data
  const lastDeployment = await scope.get<string>("lastDeployment");
  console.log(`Last deployed: ${lastDeployment}`);
  
  // Delete data
  await scope.delete("lastDeployment");
});
Scope state is separate from resource state and persists across deployments.

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Physical Name Generation

Scopes provide utilities for generating deterministic resource names: 
await alchemy.run("services", async (scope) => {
  const name = scope.createPhysicalName("api");
  // Returns: "my-app-services-api-dev"
  
  const shortName = scope.createPhysicalName("db", "-", 20);
  // Returns: "my-app-services-d" (truncated to 20 chars)
});
Format: {appName}-{scope-chain}-{id}-{stage}

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Provider Credentials

Scopes can override provider credentials: 
declare module "alchemy" {
  interface ProviderCredentials {
    aws?: {
      accessKeyId: string;
      secretAccessKey: string;
      region: string;
    };
  }
}

const app = await alchemy("my-app", {
  aws: {
    accessKeyId: process.env.AWS_ACCESS_KEY_ID!,
    secretAccessKey: process.env.AWS_SECRET_ACCESS_KEY!,
    region: "us-east-1"
  }
});

await alchemy.run("eu-services", {
  aws: {
    ...app.providerCredentials.aws,
    region: "eu-west-1"  // Override region for this scope
  }
}, async (scope) => {
  // Resources in this scope use eu-west-1
});

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Scope Lifecycle

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Initialization

Scopes are initialized when created: 
const app = await alchemy("my-app");
// State store is initialized
// Stage scope is created

await alchemy.run("services", async (scope) => {
  // Child scope is initialized
  // Resources can be created
});
// Child scope is automatically finalized

await app.finalize();
// Root and stage scopes are finalized
// Orphaned resources are cleaned up

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Finalization

Finalization handles cleanup and orphan detection:
1

Execute deferred operations

Any operations registered with scope.defer() are executed
2

Finalize child scopes

All child scopes are finalized recursively
3

Detect orphaned resources

Resources that exist in state but not in code are identified
4

Destroy orphans

Orphaned resources are deleted using the configured destroy strategy
5

Cleanup processes

Any cleanup functions registered with scope.onCleanup() are called
const app = await alchemy("my-app");

// Create resources
const worker = await Worker("api", {
  entrypoint: "./src/api.ts"
});

// This is critical - finalizes scopes and cleans up orphans
await app.finalize();
Always call app.finalize() at the end of your script. Without it, orphaned resources won’t be cleaned up.

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Process Management

Scopes can spawn and manage long-running processes: 
await alchemy.run("dev-server", async (scope) => {
  // Spawn a process that's automatically tracked
  const url = await scope.spawn("vite", {
    command: "vite",
    args: ["--port", "3000"],
    extract: (line) => {
      const match = line.match(/Local:\s+(http:\/\/[^\s]+)/);
      return match?.[1];
    }
  });
  
  console.log(`Dev server running at: ${url}`);
});
Processes spawned with scope.spawn() are automatically stopped when the process exits.

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Cleanup Handlers

Register cleanup functions to run when the process exits: 
await alchemy.run("tunnel", async (scope) => {
  const tunnel = await startTunnel();
  
  scope.onCleanup(async () => {
    console.log("Closing tunnel...");
    await tunnel.close();
  });
});

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Scope Isolation

Each scope maintains isolated state: 
const app = await alchemy("my-app");

await alchemy.run("api", async (apiScope) => {
  await apiScope.set("version", "1.0.0");
});

await alchemy.run("worker", async (workerScope) => {
  const version = await workerScope.get("version");
  console.log(version); // undefined - different scope
});

await app.finalize();

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Error Handling

Scopes track errors and propagate them: 
await alchemy.run("failing-service", async (scope) => {
  try {
    const worker = await Worker("api", {
      entrypoint: "./invalid-path.ts"  // This will fail
    });
  } catch (error) {
    scope.fail();
    throw error;
  }
});
// Scope is marked as failed
// Finalization will skip orphan cleanup for failed scopes

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Adoption Mode

Adopt existing resources that aren’t yet managed: 
bun ./alchemy.run.ts --adopt

const app = await alchemy("my-app", {
  adopt: true
});

// Will adopt existing resources instead of erroring on conflicts
const bucket = await R2Bucket("existing-bucket", {
  name: "my-existing-bucket"
});
Adoption is useful when migrating existing infrastructure to Alchemy.

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Quiet Mode

Suppress creation/update/deletion logs: 
bun ./alchemy.run.ts --quiet

const app = await alchemy("my-app", {
  quiet: true
});

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Best Practices

1

Use meaningful scope names

Choose names that describe the purpose: "api", "database", "storage"
2

Organize by lifecycle

Group resources that should be deployed/destroyed together
3

Leverage scope chain

Access parent scope properties via scope.parent when needed
4

Always finalize

Call await app.finalize() to ensure proper cleanup
5

Use stage isolation

Maintain separate stages for dev, staging, and production

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Advanced Patterns

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Conditional Scopes

Create scopes conditionally: 
const app = await alchemy("my-app");

if (app.stage === "prod") {
  await alchemy.run("monitoring", async () => {
    // Production-only monitoring resources
  });
}

await app.finalize();

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Scoped Secrets

Different scopes can use different passwords: 
await alchemy.run("secure-service", {
  password: process.env.SECURE_PASSWORD
}, async (scope) => {
  // Secrets in this scope use SECURE_PASSWORD
  const apiKey = alchemy.secret(process.env.API_KEY);
});

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Next Steps

Resources

Learn about creating and managing resources

State Management

Understand how state is stored and managed

Secrets

Secure sensitive configuration values

Lifecycle

Deep dive into deployment phases

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