# App development workflow

The easiest way to get started with the Hypersync SDK is to start with one of the sample apps in the [Hypersync SDK Samples GitHub repository](https://github.com/Hyperproof/hypersync-sdk-samples). This article explains how to install and update the [Open Library sample app](https://github.com/Hyperproof/hypersync-sdk-samples/tree/main/apps/open-library), located in the repository. Once you complete the steps below, you should have a good idea of the development workflow for your own custom Hypersync app.

> **Note**: The Open Library Hypersync app imports book and author information from a the public [Open Library API](https://openlibrary.org/developers/api). This Hypersync app has been provided for illustrative purposes only. This kind of information typically isn't relevant to a compliance program.


## Importing using the Hyperproof CLI

Custom Hypersync apps are added to a Hyperproof organization using the [Hyperproof CLI](/hypersync-sdk/sdk-017-hyperproof-cli). If you haven't already, install the CLI for your operating system.

### CLI authorization

After installing the CLI, you first need to sign in using this command:


```
hp signin
```

> **Note**: For customers with Hyperproof EU or Hyperproof GOV environments, use the following commands. For additional information, use `hp signin -help`.

```
hp signin --domain hyperproof.eu
```
OR

```
hp signin --domain hyperproofgov.app
```


This command opens a new browser window, allowing you to sign in (if you're not already signed in) and then authorize CLI access to your Hyperproof organization.

> **Note**: If you're a member of more than one organization, you'll be asked to choose the organization on the authorization page.


> **Note**: Be sure to select your "sandbox" organization if you have one available.


### Importing your Hypersync app

Follow the steps below to import a custom Hyperysnc app.

1. Locate the `apps/open-library/` directory in your clone of the Hypersync SDK Samples repository.
2. Copy the folder and store it on your computer.
> **Tip**: Rename the folder to avoid possible confusion.
3. Open terminal, then navigate to the root of the new folder.
4. Ensure the following package dependencies are installed:
> 
```
yarn install
```
5. Because the Open Library sample is written in TypeScript, you need to build the project:
> 
```
yarn build
```
6. Import the Open Library Hypersync app using this command:
> 
```
hp customapps import -d .
```


You should see console output like this:


```
janedoe:mycomputer:~/code/open-library:$ hp customapps import -d .
Creating a new custom app................
Custom app import complete.
```

Note that the import may take a minute or two to complete. Once it's done, you can test your app in Hyperproof.

### Using your Hypersync app

1. Navigate to `https://hyperproof.io` and log in to your development organization.
2. Navigate to any control or label that you have permissions to access.
3. Select the **Automations** tab.
4. Click the **New Hypersync** button.
The **New Hypersync** wizard opens.
> **Tip**: All of the built-in Hypersyncs are displayed at the top of the first page. Scroll to the bottom of the list to locate the Open Library Hypersync app. This is the app you'll use to build a new Hypersync.
5. Click the **Open Library** icon.
6. From the **Create Connection** page, click **Next**.
> **Note**: Because the Open Library API is anonymous, there is no need for you to provide any credentials like you will in most other Hypersyncs.
7. Choose **Books by Author** as the proof type.
8. Enter "Gibson, William" into the search field.
9. Choose "William F. Gibson" from the **Author** list.
10. Click **Next**.
11. On the **Configure Workflow** page, choose **New Files**.
12. Click **Next**.
13. Click **Save and Sync**.
Your custom app retrieves the list of books written by William F. Gibson, then generates a PDF that lists those books.


### Updating your Hypersync app

Because custom Hypersync apps are built as Node.js modules, updating them is simple and flexible. Many components within a Hypersync app are defined in easily editable JSON files, allowing you to make configuration changes without modifying any code.

After making changes to your app, you’re only a few steps away from publishing those updates to your Hyperproof organization.

1. Open your text editor.
2. Edit the `json/proof/booksByAuthor.json` file in your Open Library project.
This `.json` file describes one proof type in the Open Library application.
3. Find the `key` property block. Move it down below the `updated` property block.

```
...
      {
        "property": "updated",
        "label": "{{messages.LABEL_UPDATED}}",
        "width": "100px",
        "type": "text"
      },
      {
        "property": "key",
        "label": "{{messages.LABEL_KEY}}",
        "width": "200px",
        "type": "text"
      }
...
```
4. Save the `booksByAuthor.json`.
5. In terminal, run:

```
yarn build
```
6. Run the following command to update your custom app in Hyperproof:

```
hp customapps import -d .
```


That’s it—you’ve successfully made your first edit to an installed Hypersync app!

Now, open Hyperproof in your browser and re-run the Hypersync you created earlier. You should see the `Key` column displayed on the right side of the table, confirming that your update was applied successfully.

## Uninstalling your Hypersync app

The Hyperproof CLI makes uninstalling your app simple.

1. Run this command to see a list of the custom Hypersync apps you have installed:

```
hp customapps list
```
2. Copy the ID value of the app you want to uninstall.
3. Run the following command to uninstall the app:

```
hp customapps delete --id <ID>
```


> **Note**: When a custom Hypersync app is uninstalled, it's no longer available to your users via the **New Hypersync** wizard. Any proof brought into Hyperproof by a Hypersync created with the app remains in the organization via the **Proof** tab.