---
lang: en
title: 'API docs: core.application.start'
keywords: LoopBack 4.0, LoopBack 4
sidebar: lb4_sidebar
permalink: /doc/en/lb4/apidocs.core.application.start.html
---

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[Home](./index.md) &gt; [@loopback/core](./core.md) &gt; [Application](./core.application.md) &gt; [start](./core.application.start.md)

## Application.start() method

Start the application, and all of its registered observers.

<b>Signature:</b>

```typescript
start(): Promise<void>;
```
<b>Returns:</b>

`Promise<void>`