# OpenAPI-to-GraphQL Quickstart tutorial

The purpose of this tutorial is to show how easy it is to use OpenAPI-to-GraphQL CLI.

With just a single command line instruction, `openapi-to-graphql <OAS JSON file path or remote url>`, you can get a GraphQL server running.

Please note that while the CLI tool will satisfy most needs, it does not offer the flexibility or functionality of OpenAPI-to-GraphQL's intended usage, as an integrated library. See the [README.md](../../README.md) for more information.

## Video demo

[![OpenAPI-to-GraphQL](../conveyor_belt.png)](https://www.youtube.com/watch?v=4TrHUBJElrk "Click here to watch!")

## Do it yourself

### Make sure you have installed Node.js

Before you install OpenAPI-to-GraphQL, make sure to download and install Node.js (version 8.9.x or higher), a JavaScript runtime.

To install Node.js, click [here](https://nodejs.org/en/download/).

### Install OpenAPI-to-GraphQL

OpenAPI-to-GraphQL can be used either as a library, or via its Command Line Interface (CLI). To install the CLI tool, run the following command.

```sh
npm i -g openapi-to-graphql-cli
```

### Save or locate the OAS

OpenAPI-to-GraphQL relies on the OpenAPI Specification (OAS) of an existing API to create a GraphQL interface around that API. OpenAPI-to-GraphQL can also retrieve a web-hosted OAS.

If you are using LoopBack, you can simply copy the URL location of the web-hosted OAS, which should be located at http://localhost:3001/openapi.json after starting the API.

```sh
# in the LoopBack project folder:
npm start
```

***

If you want to generate a GraphQL interface for another API, make sure that API is running and proceed in the same way or save the OAS.

### Start GraphQL server

Once OpenAPI-to-GraphQL is installed and the OAS is obtained, you can create and start the GraphQL server. The created GraphQL server is then accessible by default at [http://localhost:3000/graphql](http://localhost:3000/graphql).

You can specify a local file containing the OAS specification or a remote url such as `http://localhost:3001/openapi.json`. 

```sh
openapi-to-graphql <OAS JSON file path or remote url> 
```