wrangler types

The wrangler types command generates TypeScript type definitions from your Worker configuration, providing type safety for your Worker’s environment bindings.

wrangler types [path]

path

string

default:"worker-configuration.d.ts"

The path to the declaration file for the generated types

Options

--env-interface

string

default:"Env"

The name of the generated environment interface

--include-runtime

boolean

default:"true"

Include runtime types in the generated types

--include-env

boolean

default:"true"

Include Env types in the generated types

--strict-vars

boolean

default:"true"

Generate literal and union types for variables

--check

boolean

Check if the types at the provided path are up to date without regenerating them

Example

# Generate types with default settings
wrangler types

# Generate types to a specific file
wrangler types src/worker-env.d.ts

# Generate with custom interface name
wrangler types --env-interface MyEnv

# Generate only environment types (no runtime types)
wrangler types --include-runtime false

# Check if types are up to date
wrangler types --check

What Gets Generated

The wrangler types command generates TypeScript declarations for:

Environment Bindings

KV Namespaces - KVNamespace types for Key-Value stores
R2 Buckets - R2Bucket types for object storage
D1 Databases - D1Database types for SQL databases
Durable Objects - Typed DurableObjectNamespace with your class
Service Bindings - Service or Fetcher types for Worker-to-Worker communication
AI Bindings - Ai types for AI models
Workflows - Workflow types with typed parameters
Analytics Engine - AnalyticsEngine types
Queues - Queue types for message queues

Variables and Secrets

Vars - Typed based on their values (string, number, boolean, object)
Secrets - Always typed as string

Runtime Types

When --include-runtime is true (default), generates types for:

Workers Runtime APIs
Request/Response types
Compatible Node.js APIs (when using nodejs_compat)

Usage in Your Worker

After generating types, use them in your Worker:

index.ts

// The Env interface is automatically available
export default {
  async fetch(request: Request, env: Env, ctx: ExecutionContext): Promise<Response> {
    // env is now fully typed with your bindings
    const value = await env.MY_KV.get('key');
    const result = await env.MY_DB.prepare('SELECT * FROM users').all();
    
    return new Response('Hello');
  }
};

Configuration Example

Given this wrangler.json configuration:

wrangler.json

{
  "name": "my-worker",
  "main": "src/index.ts",
  "compatibility_date": "2024-01-01",
  "kv_namespaces": [
    { "binding": "MY_KV", "id": "abc123" }
  ],
  "r2_buckets": [
    { "binding": "MY_BUCKET", "bucket_name": "my-bucket" }
  ],
  "d1_databases": [
    { "binding": "MY_DB", "database_id": "def456" }
  ],
  "vars": {
    "ENVIRONMENT": "production",
    "MAX_RETRIES": 3,
    "FEATURE_FLAGS": { "newUI": true }
  }
}

Running wrangler types generates:

worker-configuration.d.ts

/* eslint-disable */
// Generated by Wrangler by running `wrangler types` (hash: abc123def456)

declare namespace Cloudflare {
  interface Env {
    MY_KV: KVNamespace;
    MY_BUCKET: R2Bucket;
    MY_DB: D1Database;
    ENVIRONMENT: "production";
    MAX_RETRIES: 3;
    FEATURE_FLAGS: {"newUI":true};
  }
}

interface Env extends Cloudflare.Env {}

// Begin runtime types
// ... Workers runtime types ...

Multi-Environment Types

When you have multiple environments defined in your configuration, wrangler types generates separate interfaces for each:

wrangler.json

{
  "name": "my-worker",
  "kv_namespaces": [
    { "binding": "SHARED_KV", "id": "shared-123" }
  ],
  "env": {
    "staging": {
      "kv_namespaces": [
        { "binding": "STAGING_KV", "id": "staging-123" }
      ]
    },
    "production": {
      "kv_namespaces": [
        { "binding": "PROD_KV", "id": "prod-123" }
      ]
    }
  }
}

Generates:

declare namespace Cloudflare {
  interface EnvStaging {
    STAGING_KV: KVNamespace;
    SHARED_KV: KVNamespace;
  }
  
  interface EnvProduction {
    PROD_KV: KVNamespace;
    SHARED_KV: KVNamespace;
  }
  
  interface Env {
    SHARED_KV: KVNamespace;
    STAGING_KV?: KVNamespace;
    PROD_KV?: KVNamespace;
  }
}

TypeScript Configuration

Add the generated types to your tsconfig.json:

tsconfig.json

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "ES2022",
    "lib": ["ES2022"],
    "types": [
      "@cloudflare/workers-types"
    ]
  },
  "include": [
    "src/**/*",
    "worker-configuration.d.ts"
  ]
}

Workflow Integration

Generate types initially

wrangler types

Add to version control

git add worker-configuration.d.ts
git commit -m "Add generated Worker types"

Regenerate after config changes

Whenever you modify your wrangler.json (add bindings, change vars, etc.), regenerate types:

wrangler types

Verify types are current in CI

Add a check to your CI pipeline:

# This will fail if types are out of date
wrangler types --check

Use types in your code

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    // Full type safety for all bindings
    const data = await env.MY_KV.get('key');
    return new Response(data);
  }
};

Best Practices

Regenerate after configuration changes - Run wrangler types whenever you modify wrangler.json
Commit generated types - Check the generated .d.ts file into version control
Use in CI - Add wrangler types --check to your CI pipeline to ensure types are up to date
Custom interface names - Use --env-interface if you need to avoid naming conflicts
Keep types location consistent - Use the same path across your team

Strict Vars Mode

When --strict-vars is enabled (default), variables are typed with their exact values:

// With --strict-vars (default)
ENVIRONMENT: "production" | "staging"  // literal union type
MAX_RETRIES: 3                          // literal number

// With --strict-vars false
ENVIRONMENT: string                     // generic string
MAX_RETRIES: number                     // generic number

Strict mode provides better type safety by catching typos and invalid values at compile time.

Module Types

Types are also generated for module imports defined in your configuration:

wrangler.json

{
  "rules": [
    { "type": "CompiledWasm", "globs": ["**/*.wasm"] },
    { "type": "Text", "globs": ["**/*.txt"] }
  ]
}

Generates:

declare module "*.wasm" {
  const value: WebAssembly.Module;
  export default value;
}

declare module "*.txt" {
  const value: string;
  export default value;
}

Troubleshooting

Types out of date warning during wrangler dev:

Your types might be out of date. Re-run `wrangler types` to ensure your types are correct.

Solution: Run wrangler types to regenerate. Non-Wrangler .d.ts file exists error:

A non-Wrangler worker-configuration.d.ts already exists

Solution: Rename the existing file or use a different path with wrangler types custom-path.d.ts. Path doesn’t point to a declaration file:

The provided output path 'types.ts' does not point to a declaration file

Solution: Use .d.ts extension: wrangler types types.d.ts.

Essential Commands

Version Management

Storage Commands

Service Commands

Pages Commands

Configuration

Options

Example

What Gets Generated

Environment Bindings

Variables and Secrets

Runtime Types

Usage in Your Worker

Configuration Example

Multi-Environment Types

TypeScript Configuration

Workflow Integration

Best Practices

Strict Vars Mode

Module Types

Troubleshooting

Build docs developers (and LLMs) love

Essential Commands

Version Management

Storage Commands

Service Commands

Pages Commands

Configuration

Documentation Index

​Options

​Example

​What Gets Generated

​Environment Bindings

​Variables and Secrets

​Runtime Types

​Usage in Your Worker

​Configuration Example

​Multi-Environment Types

​TypeScript Configuration

​Workflow Integration

​Best Practices

​Strict Vars Mode

​Module Types

​Troubleshooting

Build docs developers (and LLMs) love

Options

Example

What Gets Generated

Environment Bindings

Variables and Secrets

Runtime Types

Usage in Your Worker

Configuration Example

Multi-Environment Types

TypeScript Configuration

Workflow Integration

Best Practices

Strict Vars Mode

Module Types

Troubleshooting