workflow/docs/api-reference/workflow-nest/nest-local-builder.mdx

Workflow SDK - Build durable, resilient, and observable workflows

---
title: NestLocalBuilder
description: Builder that compiles workflow files into bundles for NestJS apps.
type: reference
summary: Use NestLocalBuilder to build workflow bundles programmatically in a NestJS project.
prerequisites:
  - /docs/getting-started/nestjs
---

Builder that scans a NestJS project for workflow files and compiles them into the step, workflow, and webhook bundles plus a manifest. [`WorkflowModule.forRoot()`](/docs/api-reference/workflow-nest/workflow-module) creates and runs one automatically on startup. Instantiate it yourself only when you need to build bundles outside the module lifecycle (e.g. a custom build script for production with `skipBuild`).

## Usage

```typescript title="scripts/build-workflows.ts" lineNumbers
import { NestLocalBuilder } from "workflow/nest/builder"; // [!code highlight]

const builder = new NestLocalBuilder({
  dirs: ["src"],
});

await builder.build(); // [!code highlight]

console.log(`Workflow bundles written to ${builder.outDir}`);
```

## API signature

### Constructor

`new NestLocalBuilder(options?)` creates a builder for the given options.

### Parameters

| Parameter | Type | Description |
| --- | --- | --- |
| `options` | `NestBuilderOptions` | Optional. Configures the workflow build. |

#### NestBuilderOptions

| Option | Type | Default | Description |
| --- | --- | --- | --- |
| `workingDir` | `string` | `process.cwd()` | Working directory for the NestJS application. |
| `dirs` | `string[]` | `['src']` | Directories to scan for workflow files. |
| `outDir` | `string` | `'.nestjs/workflow'` (relative to `workingDir`) | Output directory for generated workflow bundles. |
| `watch` | `boolean` | `false` | Enable watch mode for development. |
| `moduleType` | `'es6' \| 'commonjs'` | `'es6'` | SWC module compilation type. When `'commonjs'`, the builder rewrites externalized imports in the steps bundle to use `require()` through `createRequire`, avoiding ECMAScript module (ESM) and CommonJS (CJS) named-export interop issues with SWC's output. |
| `distDir` | `string` | `'dist'` | Directory where NestJS compiles `.ts` source files to `.js` (relative to `workingDir`). Used when `moduleType` is `'commonjs'` to resolve compiled file paths. Should match the `outDir` in your `tsconfig.json`. |
| `sourcemap` | `boolean \| 'inline' \| 'linked' \| 'external' \| 'both'` | `'inline'` (dev) / `false` (prod) | Controls source maps on generated workflow bundles. Accepts the same values as esbuild's `sourcemap` option. Defaults to `'inline'` in development and `false` in production. Can also be set via the `WORKFLOW_SOURCEMAP` environment variable. |

### Methods

#### `build()`

Builds the workflow bundles. Writes `steps.mjs`, `workflows.mjs`, `webhook.mjs`, and `manifest.json` to the output directory (plus a `.gitignore` covering the generated files when not deploying to Vercel). Returns `Promise<void>`.

### Properties

#### `outDir`

Read-only getter that returns the output directory for generated workflow bundles: the `outDir` option as passed, or the default `.nestjs/workflow` resolved against `workingDir`.

### Returns

The constructor returns a `NestLocalBuilder` instance.