diff --git a/@platform/codebase/@features/platform-api/src/app.module.ts b/@platform/codebase/@features/platform-api/src/app.module.ts
new file mode 100644
index 0000000..3d89616
--- /dev/null
+++ b/@platform/codebase/@features/platform-api/src/app.module.ts
@@ -0,0 +1,38 @@
+import { Module } from '@nestjs/common';
+import { ConfigModule } from '@nestjs/config';
+import { APP_GUARD } from '@nestjs/core';
+import { TypeOrmModule } from '@nestjs/typeorm';
+
+import { AuthModule } from './auth/auth.module.js';
+import { QuinnSsoGuard } from './auth/quinn-sso.guard.js';
+import { CacheInvalidateModule } from './common/cache-invalidate.module.js';
+import { databaseConfig } from './config/database.config.js';
+import { HealthModule } from './health/health.module.js';
+import { AgentActionsModule } from './modules/agent-actions/agent-actions.module.js';
+import { ContentPlansModule } from './modules/content-plans/content-plans.module.js';
+import { ContentPostsModule } from './modules/content-posts/content-posts.module.js';
+
+@Module({
+  imports: [
+    ConfigModule.forRoot({
+      isGlobal: true,
+      cache: true,
+      envFilePath: ['.env.local', '.env'],
+    }),
+    TypeOrmModule.forRootAsync(databaseConfig),
+    CacheInvalidateModule,
+    AuthModule,
+    HealthModule,
+    // V3 domain modules — add new modules here as they land.
+    // P0 ships content-plans + content-posts + agent-actions (the verification-gate trio).
+    // P1+ adds: users, orgs, personas, content-assets, engagement-events.
+    ContentPlansModule,
+    ContentPostsModule,
+    AgentActionsModule,
+  ],
+  providers: [
+    // Global auth guard. Federates against quinn.sso (v2). Bypassed by @Public()-decorated routes.
+    { provide: APP_GUARD, useClass: QuinnSsoGuard },
+  ],
+})
+export class AppModule {}
diff --git a/@platform/codebase/@features/platform-api/src/health/health.module.ts b/@platform/codebase/@features/platform-api/src/health/health.module.ts
new file mode 100644
index 0000000..f09672b
--- /dev/null
+++ b/@platform/codebase/@features/platform-api/src/health/health.module.ts
@@ -0,0 +1,25 @@
+import { Controller, Get, Module } from '@nestjs/common';
+import { ApiTags } from '@nestjs/swagger';
+
+import { Public } from '../auth/public.decorator.js';
+
+interface HealthResponse {
+  status: 'ok';
+  service: 'platform.api';
+  ts: string;
+}
+
+@ApiTags('health')
+@Controller('health')
+class HealthController {
+  @Get()
+  @Public()
+  check(): HealthResponse {
+    return { status: 'ok', service: 'platform.api', ts: new Date().toISOString() };
+  }
+}
+
+@Module({
+  controllers: [HealthController],
+})
+export class HealthModule {}
diff --git a/@platform/codebase/@features/platform-api/src/main.ts b/@platform/codebase/@features/platform-api/src/main.ts
new file mode 100644
index 0000000..3943f9b
--- /dev/null
+++ b/@platform/codebase/@features/platform-api/src/main.ts
@@ -0,0 +1,47 @@
+import 'reflect-metadata';
+
+import { Logger, ValidationPipe } from '@nestjs/common';
+import { ConfigService } from '@nestjs/config';
+import { NestFactory } from '@nestjs/core';
+import { DocumentBuilder, SwaggerModule } from '@nestjs/swagger';
+
+import { AppModule } from './app.module.js';
+
+async function bootstrap(): Promise<void> {
+  const app = await NestFactory.create(AppModule, { bufferLogs: true });
+  const config = app.get(ConfigService);
+  const logger = new Logger('Bootstrap');
+
+  app.useGlobalPipes(
+    new ValidationPipe({
+      whitelist: true,
+      forbidNonWhitelisted: true,
+      transform: true,
+      transformOptions: { enableImplicitConversion: false },
+    }),
+  );
+
+  app.setGlobalPrefix('api/v1', { exclude: ['health', 'health/(.*)'] });
+
+  if (config.get<string>('NODE_ENV') !== 'production') {
+    const swaggerConfig = new DocumentBuilder()
+      .setTitle('platform.api')
+      .setDescription('V3 platform data plane — multi-tenant CRUD over platform.db')
+      .setVersion('0.1.0')
+      .addBearerAuth()
+      .build();
+    const document = SwaggerModule.createDocument(app, swaggerConfig);
+    SwaggerModule.setup('docs', app, document);
+  }
+
+  const port = config.get<number>('PLATFORM_API_PORT', 3060);
+  await app.listen(port, '0.0.0.0');
+
+  logger.log(`platform.api listening on :${port} (env=${config.get('NODE_ENV') ?? 'development'})`);
+}
+
+bootstrap().catch((err: unknown) => {
+  const logger = new Logger('Bootstrap');
+  logger.error('Fatal bootstrap error', err instanceof Error ? err.stack : String(err));
+  process.exit(1);
+});