# Guide - Authentication

### Twitter
1. Sign-in or sign-up for a Twitter account
2. Go to the Twitter Application management page [here](https://apps.twitter.com/)
3. Click on the **Create New App** button to create a new Twitter app:

![create-twitter-app](images/auth/create-twitter-app.png)

4. Fill out the create application form, check the developer agreement box, and click **Create Your Twitter Application**

![register-twitter-application](images/auth/register-twitter-application.png)

*Note: you may have to register your phone number with Twitter to create a Twitter application*

To do this Click your profile icon --> Settings and privacy --> Mobile  --> Select Country/region --> Enter phone number --> Click Continue

5. After you receive confirmation that the Twitter application was created, click **Keys and Access Tokens**

![twitter-app-confirmation](images/auth/twitter-app-confirmation.png)

6. Obtain your Twitter Consumer Key and Consumer Secret

![twitter-app-keys](images/auth/twitter-app-keys.png)

7.  Add your Consumer Key and Consumer Secret to your config.json file or pass them as environment variables:
    * config.json:
      ````javascript
      {
        "production": {
          "twitter": {
              "consumerKey": "esTCJFXXXXXXXXXXXXXXXXXXX",
              "consumerSecret": "zpCs4tU86pRVXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX"
          }
        }
      }
      ````
    * environment variables:
      ````
      HMD_TWITTER_CONSUMERKEY=esTCJFXXXXXXXXXXXXXXXXXXX
      HMD_TWITTER_CONSUMERSECRET=zpCs4tU86pRVXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
      ````

### GitHub
1. Sign-in or sign-up for a GitHub account
2. Navigate to developer settings in your GitHub account [here](https://github.com/settings/developers) and select the "OAuth Apps" tab
3. Click on the **New OAuth App** button, to create a new OAuth App: 

![create-oauth-app](images/auth/create-oauth-app.png)

4. Fill out the new OAuth application registration form, and click **Register Application**

![register-oauth-application-form](images/auth/register-oauth-application-form.png)

*Note: The callback URL is <your-hackmd-url>/auth/github/callback*

5. After successfully registering the application, you'll receive the Client ID and Client Secret for the application

![application-page](images/auth/application-page.png)

6. Add the Client ID and Client Secret to your config.json file or pass them as environment variables
    * config.json:
      ````javascript
      {
        "production": {
          "github": {
              "clientID": "3747d30eaccXXXXXXXXX",
              "clientSecret": "2a8e682948eee0c580XXXXXXXXXXXXXXXXXXXXXX"
          }
        }
      }
      ````
    * environment variables:
      ````
      HMD_GITHUB_CLIENTID=3747d30eaccXXXXXXXXX
      HMD_GITHUB_CLIENTSECRET=2a8e682948eee0c580XXXXXXXXXXXXXXXXXXXXXX
      ````