diff --git a/OWNERS b/OWNERS
index d7826a240a1..36a909af3c7 100644
--- a/OWNERS
+++ b/OWNERS
@@ -118,7 +118,7 @@ packages/cli/src/modules/data-table/                    @n8n-io/knowledge
 packages/cli/src/evaluation.ee/                         @n8n-io/ai-trust
 packages/cli/src/chat/                                  @n8n-io/ai
 packages/cli/src/tool-generation/                       @n8n-io/ai
-packages/cli/src/modules/workflow-builder/              @n8n-io/ai-assistant
+packages/modules/workflow-builder/                     @n8n-io/ai-assistant
 packages/cli/src/modules/mcp/                           @n8n-io/context
 packages/modules/quick-connect/                        @n8n-io/ai
 packages/cli/src/modules/chat-hub/                      @n8n-io/ai-assistant
diff --git a/packages/cli/package.json b/packages/cli/package.json
index fdc0f7d7244..3d6122ae9a3 100644
--- a/packages/cli/package.json
+++ b/packages/cli/package.json
@@ -159,6 +159,7 @@
     "@n8n/backend-common": "workspace:*",
     "@n8n/backend-module-insights": "workspace:*",
     "@n8n/backend-module-quick-connect": "workspace:*",
+    "@n8n/backend-module-workflow-builder": "workspace:*",
     "@n8n/backend-network": "workspace:*",
     "@n8n/backend-services": "workspace:*",
     "@n8n/blob-storage": "workspace:*",
diff --git a/packages/cli/src/modules/__tests__/workflow-builder-package.test.ts b/packages/cli/src/modules/__tests__/workflow-builder-package.test.ts
new file mode 100644
index 00000000000..eec502ef051
--- /dev/null
+++ b/packages/cli/src/modules/__tests__/workflow-builder-package.test.ts
@@ -0,0 +1,21 @@
+import { WorkflowBuilderSession } from '@n8n/backend-module-workflow-builder';
+import { ModuleMetadata } from '@n8n/decorators';
+import { Container } from '@n8n/di';
+
+import { packagedModules } from '../modules.manifest';
+
+describe('packaged Workflow Builder', () => {
+	it('loads the package entrypoint through the CLI manifest', async () => {
+		const metadata = Container.get(ModuleMetadata);
+		expect(metadata.get('workflow-builder')).toBeUndefined();
+
+		const load = packagedModules['workflow-builder'];
+		expect(load).toBeTypeOf('function');
+		await load?.();
+
+		const entry = metadata.get('workflow-builder');
+		expect(entry?.instanceTypes).toEqual(['main']);
+		const module = entry && Container.get(entry.class);
+		expect(await module?.entities?.()).toEqual([WorkflowBuilderSession]);
+	});
+});
diff --git a/packages/cli/src/modules/modules.manifest.ts b/packages/cli/src/modules/modules.manifest.ts
index 6142d7b1867..1fd7fe6499c 100644
--- a/packages/cli/src/modules/modules.manifest.ts
+++ b/packages/cli/src/modules/modules.manifest.ts
@@ -7,4 +7,5 @@ import type { PackagedModules } from '@n8n/backend-common';
 export const packagedModules: PackagedModules = {
 	insights: async () => await import('@n8n/backend-module-insights/module'),
 	'quick-connect': async () => await import('@n8n/backend-module-quick-connect/module'),
+	'workflow-builder': async () => await import('@n8n/backend-module-workflow-builder/module'),
 };
diff --git a/packages/cli/src/services/__tests__/ai-workflow-builder.service.test.ts b/packages/cli/src/services/__tests__/ai-workflow-builder.service.test.ts
index a2ee89c2e07..c343a79180c 100644
--- a/packages/cli/src/services/__tests__/ai-workflow-builder.service.test.ts
+++ b/packages/cli/src/services/__tests__/ai-workflow-builder.service.test.ts
@@ -1,6 +1,7 @@
 import type { Mock, MockedClass } from 'vitest';
 import { AiWorkflowBuilderService } from '@n8n/ai-workflow-builder';
 import type { Logger } from '@n8n/backend-common';
+import { WorkflowBuilderSessionRepository } from '@n8n/backend-module-workflow-builder';
 import type { HttpTransport, OutboundHttp, SsrfProtectionService } from '@n8n/backend-network';
 import type { GlobalConfig, SsrfProtectionConfig } from '@n8n/config';
 import { AiAssistantClient } from '@n8n_io/ai-assistant-sdk';
@@ -14,7 +15,6 @@ import { join } from 'node:path';
 
 import type { License } from '@/license';
 import { LoadNodesAndCredentials } from '@/load-nodes-and-credentials';
-import type { WorkflowBuilderSessionRepository } from '@/modules/workflow-builder';
 import type { Push } from '@/push';
 import { WorkflowBuilderService } from '@/services/ai-workflow-builder.service';
 import type { DynamicNodeParametersService } from '@/services/dynamic-node-parameters.service';
@@ -138,6 +138,14 @@ describe('WorkflowBuilderService', () => {
 	});
 
 	describe('constructor', () => {
+		it('uses the public repository constructor for dependency injection', () => {
+			const dependencies: unknown[] = Reflect.getMetadata(
+				'design:paramtypes',
+				WorkflowBuilderService,
+			);
+			expect(dependencies).toContain(WorkflowBuilderSessionRepository);
+		});
+
 		it('should initialize without creating the service immediately', () => {
 			expect(MockedAiWorkflowBuilderService).not.toHaveBeenCalled();
 		});
diff --git a/packages/cli/src/services/ai-workflow-builder.service.ts b/packages/cli/src/services/ai-workflow-builder.service.ts
index b2d7aa95bb3..c1c61dbea53 100644
--- a/packages/cli/src/services/ai-workflow-builder.service.ts
+++ b/packages/cli/src/services/ai-workflow-builder.service.ts
@@ -5,6 +5,7 @@ import {
 	ChatPayload,
 } from '@n8n/ai-workflow-builder';
 import { Logger } from '@n8n/backend-common';
+import { WorkflowBuilderSessionRepository } from '@n8n/backend-module-workflow-builder';
 import { OutboundHttp, SsrfProtectionService } from '@n8n/backend-network';
 import { GlobalConfig, SsrfProtectionConfig } from '@n8n/config';
 import { BUILTIN_NODES_PACKAGES } from '@n8n/constants';
@@ -24,7 +25,6 @@ import * as path from 'path';
 import { N8N_VERSION } from '@/constants';
 import { License } from '@/license';
 import { LoadNodesAndCredentials } from '@/load-nodes-and-credentials';
-import { WorkflowBuilderSessionRepository } from '@/modules/workflow-builder';
 import { Push } from '@/push';
 import { DynamicNodeParametersService } from '@/services/dynamic-node-parameters.service';
 import { UrlService } from '@n8n/backend-services';
diff --git a/packages/cli/tsconfig.json b/packages/cli/tsconfig.json
index 56e54f4a184..727e50edc5c 100644
--- a/packages/cli/tsconfig.json
+++ b/packages/cli/tsconfig.json
@@ -42,6 +42,7 @@
 		{ "path": "../@n8n/backend-services/tsconfig.build.json" },
 		{ "path": "../modules/insights/backend/tsconfig.build.json" },
 		{ "path": "../modules/quick-connect/backend/tsconfig.build.json" },
+		{ "path": "../modules/workflow-builder/backend/tsconfig.build.json" },
 		{ "path": "../@n8n/backend-test-utils/tsconfig.build.json" },
 		{ "path": "../@n8n/blob-storage/tsconfig.build.json" },
 		{ "path": "../@n8n/di/tsconfig.build.json" },
diff --git a/packages/cli/vitest.config.base.ts b/packages/cli/vitest.config.base.ts
index 4172ddcd9c0..e6b10bd1edb 100644
--- a/packages/cli/vitest.config.base.ts
+++ b/packages/cli/vitest.config.base.ts
@@ -30,6 +30,14 @@ const alias = {
 		__dirname,
 		'../modules/insights/backend/src/index.ts',
 	),
+	'@n8n/backend-module-workflow-builder/module': path.resolve(
+		__dirname,
+		'../modules/workflow-builder/backend/src/workflow-builder.module.ts',
+	),
+	'@n8n/backend-module-workflow-builder': path.resolve(
+		__dirname,
+		'../modules/workflow-builder/backend/src/index.ts',
+	),
 	'@n8n/mcp-apps/server': path.resolve(__dirname, '../@n8n/mcp-apps/src/server/index.ts'),
 	'@n8n/telemetry': path.resolve(__dirname, '../@n8n/telemetry/src'),
 	'@': path.resolve(__dirname, 'src'),
diff --git a/packages/modules/workflow-builder/backend/README.md b/packages/modules/workflow-builder/backend/README.md
new file mode 100644
index 00000000000..b0dd0149a86
--- /dev/null
+++ b/packages/modules/workflow-builder/backend/README.md
@@ -0,0 +1,17 @@
+# Workflow Builder backend
+
+This package stores Workflow Builder sessions. It owns the session entity and repository.
+
+Import `WorkflowBuilderSession`, `IWorkflowBuilderSession`, and
+`WorkflowBuilderSessionRepository` from `@n8n/backend-module-workflow-builder`.
+The public API does not register the backend module.
+
+The CLI manifest loads `@n8n/backend-module-workflow-builder/module` on demand.
+The module registers its entity before the database starts. Migrations stay in `@n8n/db`.
+
+Run `pnpm build > build.log 2>&1` before you use the package from the CLI. The build writes JavaScript and
+declarations to `dist`. It excludes tests.
+
+Run `pnpm test --maxWorkers=1` for unit tests and SQLite persistence tests.
+Run `pnpm test:postgres --maxWorkers=1` for persistence tests with the shared PostgreSQL harness.
+The PostgreSQL harness needs Docker.
diff --git a/packages/modules/workflow-builder/backend/oxlint.config.mts b/packages/modules/workflow-builder/backend/oxlint.config.mts
new file mode 100644
index 00000000000..23a0f5690f6
--- /dev/null
+++ b/packages/modules/workflow-builder/backend/oxlint.config.mts
@@ -0,0 +1,8 @@
+import { backendConfig } from '@n8n/oxlint-config/backend';
+import { defineConfig } from 'oxlint';
+
+export default defineConfig({
+	extends: [backendConfig],
+	options: { typeAware: true },
+	ignorePatterns: ['coverage/**', 'dist/**'],
+});
diff --git a/packages/modules/workflow-builder/backend/package.json b/packages/modules/workflow-builder/backend/package.json
new file mode 100644
index 00000000000..eec31946f89
--- /dev/null
+++ b/packages/modules/workflow-builder/backend/package.json
@@ -0,0 +1,71 @@
+{
+  "name": "@n8n/backend-module-workflow-builder",
+  "version": "0.1.0",
+  "main": "dist/index.js",
+  "module": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "exports": {
+    ".": {
+      "types": "./dist/index.d.ts",
+      "import": "./dist/index.js",
+      "require": "./dist/index.js"
+    },
+    "./module": {
+      "types": "./dist/workflow-builder.module.d.ts",
+      "import": "./dist/workflow-builder.module.js",
+      "require": "./dist/workflow-builder.module.js"
+    }
+  },
+  "files": [
+    "dist/**/*"
+  ],
+  "scripts": {
+    "clean": "rimraf dist .turbo",
+    "dev": "pnpm watch",
+    "typecheck": "tsc --noEmit",
+    "build": "tsc -p tsconfig.build.json",
+    "build:unchecked": "tsc -p tsconfig.build.json --noCheck",
+    "format": "biome format --write .",
+    "format:check": "biome ci .",
+    "lint": "oxlint --type-aware . --quiet",
+    "lint:fix": "oxlint --type-aware . --fix",
+    "watch": "tsc -p tsconfig.build.json --watch",
+    "test": "vitest run",
+    "test:unit": "vitest run",
+    "test:dev": "vitest --silent=false",
+    "test:postgres": "N8N_LOG_LEVEL=silent vitest run --config vitest.config.postgres.ts"
+  },
+  "dependencies": {
+    "@n8n/ai-workflow-builder": "workspace:*",
+    "@n8n/db": "workspace:*",
+    "@n8n/decorators": "workspace:*",
+    "@n8n/di": "workspace:*",
+    "@n8n/typeorm": "workspace:*"
+  },
+  "peerDependencies": {
+    "@langchain/core": "catalog:"
+  },
+  "devDependencies": {
+    "@langchain/core": "catalog:",
+    "@n8n/backend-common": "workspace:*",
+    "@n8n/backend-test-utils": "workspace:*",
+    "@n8n/oxlint-config": "workspace:*",
+    "@n8n/typescript-config": "workspace:*",
+    "@n8n/vitest-config": "workspace:*",
+    "n8n-containers": "workspace:*",
+    "oxlint": "catalog:",
+    "oxlint-tsgolint": "catalog:",
+    "typescript": "catalog:typescript",
+    "vite": "catalog:",
+    "vitest": "catalog:",
+    "vitest-mock-extended": "catalog:"
+  },
+  "license": "LicenseRef-n8n-sustainable-use",
+  "typesVersions": {
+    "*": {
+      "module": [
+        "dist/workflow-builder.module.d.ts"
+      ]
+    }
+  }
+}
diff --git a/packages/modules/workflow-builder/backend/src/__tests__/workflow-builder-session.integration.test.ts b/packages/modules/workflow-builder/backend/src/__tests__/workflow-builder-session.integration.test.ts
new file mode 100644
index 00000000000..63e59439797
--- /dev/null
+++ b/packages/modules/workflow-builder/backend/src/__tests__/workflow-builder-session.integration.test.ts
@@ -0,0 +1,113 @@
+import { AIMessage, HumanMessage } from '@langchain/core/messages';
+import { ModuleRegistry } from '@n8n/backend-common';
+import { createWorkflow, testDb, testModules } from '@n8n/backend-test-utils';
+import { DbConnection, User, UserRepository, WorkflowEntity, WorkflowRepository } from '@n8n/db';
+import { Container } from '@n8n/di';
+import { DataSource } from '@n8n/typeorm';
+
+import { WorkflowBuilderSession, WorkflowBuilderSessionRepository } from '../index';
+
+let repository: WorkflowBuilderSessionRepository;
+let dataSource: DataSource;
+
+beforeAll(async () => {
+	await testModules.loadModules(['workflow-builder'], {
+		'workflow-builder': async () => await import('../workflow-builder.module.js'),
+	});
+	expect(Container.get(ModuleRegistry).entities).toContain(WorkflowBuilderSession);
+	expect(Container.get(DbConnection).connectionState.connected).toBe(false);
+	await testDb.init();
+	dataSource = Container.get(DataSource);
+	repository = Container.get(WorkflowBuilderSessionRepository);
+});
+
+beforeEach(async () => {
+	await repository.delete({});
+});
+
+afterAll(async () => {
+	await testDb.terminate();
+});
+
+async function createSessionOwner() {
+	const user = await Container.get(UserRepository).save({ role: { slug: 'global:owner' } });
+	const workflow = await createWorkflow();
+	return { user, workflow, threadId: `workflow-${workflow.id}-user-${user.id}` };
+}
+
+describe('packaged session persistence', () => {
+	it('resolves relations to the shared database entities', () => {
+		const metadata = dataSource.getMetadata(WorkflowBuilderSession);
+		expect(metadata.tableNameWithoutPrefix).toBe('workflow_builder_session');
+		expect(metadata.findRelationWithPropertyPath('workflow')?.inverseEntityMetadata.target).toBe(
+			WorkflowEntity,
+		);
+		expect(metadata.findRelationWithPropertyPath('user')?.inverseEntityMetadata.target).toBe(User);
+	});
+
+	it('saves, restores, and updates one session for both thread formats', async () => {
+		const { user, workflow, threadId } = await createSessionOwner();
+		const messages = [new HumanMessage('Build a workflow'), new AIMessage('Workflow ready')];
+		await repository.saveSession(threadId, {
+			messages,
+			previousSummary: 'Workflow summary',
+			updatedAt: new Date(),
+			activeVersionCardId: 'version-card',
+			resumeAfterRestoreMessageId: 'resume-message',
+		});
+
+		expect(await repository.getSession(`${threadId}-code`)).toEqual({
+			messages,
+			previousSummary: 'Workflow summary',
+			updatedAt: expect.any(Date),
+			activeVersionCardId: 'version-card',
+			resumeAfterRestoreMessageId: 'resume-message',
+		});
+		const original = await repository.findOneByOrFail({ workflowId: workflow.id, userId: user.id });
+		expect(original.id).toMatch(/^[0-9a-f-]{36}$/);
+		expect(original.createdAt).toBeInstanceOf(Date);
+		expect(original.updatedAt).toBeInstanceOf(Date);
+		expect(original.messages.map((message) => message.type)).toEqual(['human', 'ai']);
+
+		await repository.saveSession(`${threadId}-code`, {
+			messages: [new HumanMessage('Update the workflow')],
+			updatedAt: new Date(),
+		});
+		expect(await repository.count()).toBe(1);
+		expect(await repository.findOneByOrFail({ id: original.id })).toMatchObject({
+			createdAt: original.createdAt,
+			previousSummary: null,
+			activeVersionCardId: null,
+			resumeAfterRestoreMessageId: null,
+		});
+		expect(await repository.getSession(threadId)).toMatchObject({
+			messages: [new HumanMessage('Update the workflow')],
+			previousSummary: undefined,
+		});
+
+		await repository.deleteSession(`${threadId}-code`);
+		expect(await repository.getSession(threadId)).toBeNull();
+	});
+
+	it('generates an ID and enforces the workflow and user uniqueness rule', async () => {
+		const { user, workflow } = await createSessionOwner();
+		const values = { workflowId: workflow.id, userId: user.id, messages: [] };
+		const entity = await repository.save(repository.create(values));
+		expect(entity.id).toMatch(/^[0-9a-f-]{36}$/);
+		await expect(repository.save(repository.create(values))).rejects.toThrow(/unique/i);
+	});
+
+	it.each(['workflow', 'user'] as const)(
+		'removes sessions when the %s is removed',
+		async (owner) => {
+			const { user, workflow, threadId } = await createSessionOwner();
+			await repository.saveSession(threadId, { messages: [], updatedAt: new Date() });
+			if (owner === 'workflow') {
+				await Container.get(WorkflowRepository).delete(workflow.id);
+			} else {
+				await Container.get(UserRepository).delete(user.id);
+			}
+			expect(await repository.getSession(threadId)).toBeNull();
+		},
+	);
+});
diff --git a/packages/cli/src/modules/workflow-builder/__tests__/workflow-builder-session.repository.test.ts b/packages/modules/workflow-builder/backend/src/__tests__/workflow-builder-session.repository.test.ts
similarity index 93%
rename from packages/cli/src/modules/workflow-builder/__tests__/workflow-builder-session.repository.test.ts
rename to packages/modules/workflow-builder/backend/src/__tests__/workflow-builder-session.repository.test.ts
index 62cd5274a3c..2a17e53731c 100644
--- a/packages/cli/src/modules/workflow-builder/__tests__/workflow-builder-session.repository.test.ts
+++ b/packages/modules/workflow-builder/backend/src/__tests__/workflow-builder-session.repository.test.ts
@@ -1,7 +1,7 @@
 import { AIMessage, HumanMessage } from '@langchain/core/messages';
-import { mockClear } from 'vitest-mock-extended';
-
-import { mockEntityManager } from '@test/mocking';
+import { mockInstance } from '@n8n/backend-test-utils';
+import { DataSource, EntityManager, type EntityMetadata } from '@n8n/typeorm';
+import { mock, mockClear } from 'vitest-mock-extended';
 
 import { WorkflowBuilderSession } from '../workflow-builder-session.entity';
 
@@ -25,7 +25,12 @@ vi.mock('@n8n/ai-workflow-builder', () => ({
 import { WorkflowBuilderSessionRepository } from '../workflow-builder-session.repository';
 
 describe('WorkflowBuilderSessionRepository', () => {
-	const entityManager = mockEntityManager(WorkflowBuilderSession);
+	const entityManager = mockInstance(EntityManager);
+	const dataSource = mockInstance(DataSource, {
+		manager: entityManager,
+		getMetadata: () => mock<EntityMetadata>({ target: WorkflowBuilderSession }),
+	});
+	Object.assign(entityManager, { connection: dataSource });
 	let repository: WorkflowBuilderSessionRepository;
 
 	const mockExecute = vi.fn().mockResolvedValue(undefined);
@@ -46,11 +51,7 @@ describe('WorkflowBuilderSessionRepository', () => {
 		mockQueryBuilder.values.mockClear().mockReturnThis();
 		mockQueryBuilder.orUpdate.mockClear().mockReturnThis();
 
-		// Create repository with mocked data source
-		const mockDataSource = {
-			manager: entityManager,
-		};
-		repository = new WorkflowBuilderSessionRepository(mockDataSource as never);
+		repository = new WorkflowBuilderSessionRepository(dataSource);
 		vi.spyOn(repository, 'createQueryBuilder').mockReturnValue(mockQueryBuilder as never);
 	});
 
diff --git a/packages/modules/workflow-builder/backend/src/__tests__/workflow-builder.module.test.ts b/packages/modules/workflow-builder/backend/src/__tests__/workflow-builder.module.test.ts
new file mode 100644
index 00000000000..dd258608678
--- /dev/null
+++ b/packages/modules/workflow-builder/backend/src/__tests__/workflow-builder.module.test.ts
@@ -0,0 +1,15 @@
+import { ModuleMetadata } from '@n8n/decorators';
+import { Container } from '@n8n/di';
+
+import { WorkflowBuilderSession } from '../index';
+import { WorkflowBuilderModule } from '../workflow-builder.module';
+
+describe('WorkflowBuilderModule', () => {
+	it('registers the main instance entrypoint with the public entity', async () => {
+		expect(Container.get(ModuleMetadata).get('workflow-builder')).toMatchObject({
+			class: WorkflowBuilderModule,
+			instanceTypes: ['main'],
+		});
+		expect(await new WorkflowBuilderModule().entities()).toEqual([WorkflowBuilderSession]);
+	});
+});
diff --git a/packages/modules/workflow-builder/backend/src/index.test.ts b/packages/modules/workflow-builder/backend/src/index.test.ts
new file mode 100644
index 00000000000..f9fe4633204
--- /dev/null
+++ b/packages/modules/workflow-builder/backend/src/index.test.ts
@@ -0,0 +1,17 @@
+import { ModuleMetadata } from '@n8n/decorators';
+import { Container } from '@n8n/di';
+
+describe('public API', () => {
+	it('does not register the module entrypoint', async () => {
+		const metadata = Container.get(ModuleMetadata);
+		expect(metadata.get('workflow-builder')).toBeUndefined();
+
+		const publicApi = await import('./index.js');
+
+		expect(metadata.get('workflow-builder')).toBeUndefined();
+		expect(Object.keys(publicApi).sort()).toEqual([
+			'WorkflowBuilderSession',
+			'WorkflowBuilderSessionRepository',
+		]);
+	});
+});
diff --git a/packages/cli/src/modules/workflow-builder/index.ts b/packages/modules/workflow-builder/backend/src/index.ts
similarity index 74%
rename from packages/cli/src/modules/workflow-builder/index.ts
rename to packages/modules/workflow-builder/backend/src/index.ts
index 829484eed44..ea86c8b6088 100644
--- a/packages/cli/src/modules/workflow-builder/index.ts
+++ b/packages/modules/workflow-builder/backend/src/index.ts
@@ -3,4 +3,3 @@ export {
 	type IWorkflowBuilderSession,
 } from './workflow-builder-session.entity';
 export { WorkflowBuilderSessionRepository } from './workflow-builder-session.repository';
-export { WorkflowBuilderModule } from './workflow-builder.module';
diff --git a/packages/cli/src/modules/workflow-builder/workflow-builder-session.entity.ts b/packages/modules/workflow-builder/backend/src/workflow-builder-session.entity.ts
similarity index 100%
rename from packages/cli/src/modules/workflow-builder/workflow-builder-session.entity.ts
rename to packages/modules/workflow-builder/backend/src/workflow-builder-session.entity.ts
diff --git a/packages/cli/src/modules/workflow-builder/workflow-builder-session.repository.ts b/packages/modules/workflow-builder/backend/src/workflow-builder-session.repository.ts
similarity index 100%
rename from packages/cli/src/modules/workflow-builder/workflow-builder-session.repository.ts
rename to packages/modules/workflow-builder/backend/src/workflow-builder-session.repository.ts
diff --git a/packages/cli/src/modules/workflow-builder/workflow-builder.module.ts b/packages/modules/workflow-builder/backend/src/workflow-builder.module.ts
similarity index 100%
rename from packages/cli/src/modules/workflow-builder/workflow-builder.module.ts
rename to packages/modules/workflow-builder/backend/src/workflow-builder.module.ts
diff --git a/packages/modules/workflow-builder/backend/test/setup-postgres.ts b/packages/modules/workflow-builder/backend/test/setup-postgres.ts
new file mode 100644
index 00000000000..588fd629282
--- /dev/null
+++ b/packages/modules/workflow-builder/backend/test/setup-postgres.ts
@@ -0,0 +1,6 @@
+import './setup-test-folder';
+
+import { createTestDatabaseGlobalSetup } from 'n8n-containers/test-db-global-setup';
+
+// Run migrations after the suite registers this package's entity.
+export const { setup, teardown } = createTestDatabaseGlobalSetup();
diff --git a/packages/modules/workflow-builder/backend/test/setup-test-folder.ts b/packages/modules/workflow-builder/backend/test/setup-test-folder.ts
new file mode 100644
index 00000000000..a1141bf6365
--- /dev/null
+++ b/packages/modules/workflow-builder/backend/test/setup-test-folder.ts
@@ -0,0 +1,19 @@
+import { mkdirSync, mkdtempSync, writeFileSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import { join } from 'node:path';
+
+process.env.N8N_ENCRYPTION_KEY = 'test_key';
+
+const baseDir = join(tmpdir(), 'n8n-workflow-builder-tests');
+mkdirSync(baseDir, { recursive: true });
+
+const testDir = mkdtempSync(join(baseDir, 'run-'));
+const settingsDir = join(testDir, '.n8n');
+mkdirSync(settingsDir);
+process.env.N8N_USER_FOLDER = testDir;
+process.env.N8N_ENFORCE_SETTINGS_FILE_PERMISSIONS = 'true';
+
+writeFileSync(join(settingsDir, 'config'), JSON.stringify({ encryptionKey: 'test_key' }), {
+	encoding: 'utf-8',
+	mode: 0o600,
+});
diff --git a/packages/modules/workflow-builder/backend/tsconfig.build.json b/packages/modules/workflow-builder/backend/tsconfig.build.json
new file mode 100644
index 00000000000..ac376c250d1
--- /dev/null
+++ b/packages/modules/workflow-builder/backend/tsconfig.build.json
@@ -0,0 +1,10 @@
+{
+	"extends": ["./tsconfig.json", "@n8n/typescript-config/tsconfig.build.go.json"],
+	"compilerOptions": {
+		"composite": true,
+		"rootDir": "src",
+		"outDir": "dist"
+	},
+	"include": ["src/**/*.ts"],
+	"exclude": ["src/**/__tests__/**", "src/**/*.test.ts"]
+}
diff --git a/packages/modules/workflow-builder/backend/tsconfig.json b/packages/modules/workflow-builder/backend/tsconfig.json
new file mode 100644
index 00000000000..0df0697ff59
--- /dev/null
+++ b/packages/modules/workflow-builder/backend/tsconfig.json
@@ -0,0 +1,17 @@
+{
+	"extends": [
+		"@n8n/typescript-config/tsconfig.common.go.json",
+		"@n8n/typescript-config/tsconfig.backend.go.json"
+	],
+	"compilerOptions": {
+		"emitDecoratorMetadata": true,
+		"experimentalDecorators": true,
+		"lib": ["es2023", "dom"],
+		"types": ["node", "vitest/globals"],
+		"strict": true,
+		"strictFunctionTypes": false,
+		"strictPropertyInitialization": false,
+		"useUnknownInCatchVariables": false
+	},
+	"include": ["src/**/*.ts", "test/**/*.ts", "vitest.config*.ts"]
+}
diff --git a/packages/modules/workflow-builder/backend/vitest.config.postgres.ts b/packages/modules/workflow-builder/backend/vitest.config.postgres.ts
new file mode 100644
index 00000000000..5fa6081e036
--- /dev/null
+++ b/packages/modules/workflow-builder/backend/vitest.config.postgres.ts
@@ -0,0 +1,12 @@
+import baseConfig from './vitest.config';
+
+export default {
+	...baseConfig,
+	test: {
+		...baseConfig.test,
+		include: ['src/**/*.integration.test.ts'],
+		testTimeout: 30_000,
+		hookTimeout: 30_000,
+		globalSetup: ['./test/setup-postgres.ts'],
+	},
+};
diff --git a/packages/modules/workflow-builder/backend/vitest.config.ts b/packages/modules/workflow-builder/backend/vitest.config.ts
new file mode 100644
index 00000000000..c4fd00ae6d5
--- /dev/null
+++ b/packages/modules/workflow-builder/backend/vitest.config.ts
@@ -0,0 +1,19 @@
+import { createVitestConfigWithDecorators } from '@n8n/vitest-config/node-decorators';
+import { tscDecoratorTransform } from '@n8n/vitest-config/tsc-decorator-transform';
+import { mergeConfig } from 'vite';
+import { configDefaults } from 'vitest/config';
+
+export default mergeConfig(
+	createVitestConfigWithDecorators({}, { pinCjs: ['@n8n/backend-common', '@n8n/decorators'] }),
+	{
+		plugins: [
+			tscDecoratorTransform({ filePredicate: (fileName) => /\.entity\.ts$/.test(fileName) }),
+		],
+		test: {
+			pool: 'forks',
+			setupFiles: ['./test/setup-test-folder.ts'],
+			exclude: [...configDefaults.exclude, '**/dist/**'],
+			hookTimeout: 30_000,
+		},
+	},
+);
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index dcfb25f2e85..fae88f48778 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -4835,6 +4835,9 @@ importers:
       '@n8n/backend-module-quick-connect':
         specifier: workspace:*
         version: link:../modules/quick-connect/backend
+      '@n8n/backend-module-workflow-builder':
+        specifier: workspace:*
+        version: link:../modules/workflow-builder/backend
       '@n8n/backend-network':
         specifier: workspace:*
         version: link:../@n8n/backend-network
@@ -7719,6 +7722,64 @@ importers:
         specifier: ^2.2.8
         version: 2.2.8(patch_hash=e2aee939ccac8a57fe449bfd92bedd8117841579526217bc39aca26c6b8c317f)(typescript@6.0.2)
 
+  packages/modules/workflow-builder/backend:
+    dependencies:
+      '@n8n/ai-workflow-builder':
+        specifier: workspace:*
+        version: link:../../../@n8n/ai-workflow-builder.ee
+      '@n8n/db':
+        specifier: workspace:*
+        version: link:../../../@n8n/db
+      '@n8n/decorators':
+        specifier: workspace:*
+        version: link:../../../@n8n/decorators
+      '@n8n/di':
+        specifier: workspace:*
+        version: link:../../../@n8n/di
+      '@n8n/typeorm':
+        specifier: workspace:*
+        version: link:../../../@n8n/typeorm
+    devDependencies:
+      '@langchain/core':
+        specifier: 'catalog:'
+        version: 1.2.8(@opentelemetry/api@1.9.1)(@opentelemetry/exporter-trace-otlp-proto@0.221.0(@opentelemetry/api@1.9.1))(@opentelemetry/sdk-trace-base@2.10.0(@opentelemetry/api@1.9.1))(openai@6.46.0(@aws-sdk/credential-provider-node@3.972.80)(@smithy/signature-v4@5.7.2)(ws@8.21.1(bufferutil@4.0.9)(utf-8-validate@5.0.10))(zod@3.25.76))(ws@8.21.1(bufferutil@4.0.9)(utf-8-validate@5.0.10))
+      '@n8n/backend-common':
+        specifier: workspace:*
+        version: link:../../../@n8n/backend-common
+      '@n8n/backend-test-utils':
+        specifier: workspace:*
+        version: link:../../../@n8n/backend-test-utils
+      '@n8n/oxlint-config':
+        specifier: workspace:*
+        version: link:../../../@n8n/oxlint-config
+      '@n8n/typescript-config':
+        specifier: workspace:*
+        version: link:../../../@n8n/typescript-config
+      '@n8n/vitest-config':
+        specifier: workspace:*
+        version: link:../../../@n8n/vitest-config
+      n8n-containers:
+        specifier: workspace:*
+        version: link:../../../quality/environments/containers
+      oxlint:
+        specifier: 'catalog:'
+        version: 1.78.0(oxlint-tsgolint@0.21.1)
+      oxlint-tsgolint:
+        specifier: 'catalog:'
+        version: 0.21.1
+      typescript:
+        specifier: catalog:typescript
+        version: 7.0.2
+      vite:
+        specifier: 'catalog:'
+        version: 8.0.2(@emnapi/core@1.11.2)(@emnapi/runtime@1.11.2)(@types/node@20.19.41)(esbuild@0.28.1)(jiti@2.6.1)(sass-embedded@1.98.0)(sass@1.98.0)(terser@5.16.1)(tsx@4.19.3)(yaml@2.8.3)
+      vitest:
+        specifier: 'catalog:'
+        version: 5.0.1(@opentelemetry/api@1.9.1)(@types/node@20.19.41)(@vitest/browser-playwright@5.0.1)(@vitest/coverage-istanbul@5.0.1)(@vitest/coverage-v8@5.0.1)(@vitest/ui@5.0.1)(jsdom@23.0.1(bufferutil@4.0.9)(supports-color@8.1.1)(utf-8-validate@5.0.10))(vite@8.0.2(@emnapi/core@1.11.2)(@emnapi/runtime@1.11.2)(@types/node@20.19.41)(esbuild@0.28.1)(jiti@2.6.1)(sass-embedded@1.98.0)(sass@1.98.0)(terser@5.16.1)(tsx@4.19.3)(yaml@2.8.3))
+      vitest-mock-extended:
+        specifier: 'catalog:'
+        version: 3.1.0(typescript@7.0.2)(vitest@5.0.1)
+
   packages/node-dev:
     dependencies:
       '@n8n/di':