---
lang: en
title: 'API docs: openapi-spec-builder.anopenapispec'
keywords: LoopBack 4.0, LoopBack 4, Node.js, TypeScript, OpenAPI
sidebar: lb4_sidebar
editurl: https://github.com/loopbackio/loopback-next/tree/master/packages/openapi-spec-builder
permalink: /doc/en/lb4/apidocs.openapi-spec-builder.anopenapispec.html
---

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[Home](./index.md) &gt; [@loopback/openapi-spec-builder](./openapi-spec-builder.md) &gt; [anOpenApiSpec](./openapi-spec-builder.anopenapispec.md)

## anOpenApiSpec() function

Create a new instance of OpenApiSpecBuilder.

**Signature:**

```typescript
export declare function anOpenApiSpec(): OpenApiSpecBuilder;
```
**Returns:**

[OpenApiSpecBuilder](./openapi-spec-builder.openapispecbuilder.md)