This is a simple Micropub client for creating text posts on your own website. To use it, you will need to turn your website into an OAuth provider, and implement a Micropub endpoint that this app will send requests to.
Once you've signed in, you'll see an interface like the one shown which you can use to write a post. Clicking "post" will make a Micropub request to your endpoint.
The Creating a Micropub Endpoint tutorial will walk you through how to handle incoming POST requests from apps like this.
You can provide a list of supported syndication targets that will appear as checkboxes when you are creating a new post.
To do this, your Micropub endpoint will need to respond to a GET request containing a query string of q=syndicate-to. This request will be made with the access token that was generated for this app, so you can choose which syndication targets you want to allow this app to use.
Below is the request and expected response that Quill looks for.
GET /micropub?q=syndicate-to HTTP/1.1
Authorization: Bearer xxxxxxxxxx
HTTP/1.1 200 OK
Content-type: application/x-www-form-urlencoded
syndicate-to[]=twitter.com%2Faaronpk&syndicate-to[]=facebook.com%2Faaronpk
The response should be a form-encoded reply with an array, syndicate-to of all the supported syndication targets. The actual values are up to your Micropub endpoint, but a good convention is to use the domain name of the service (e.g. twitter.com), or domain name and username (e.g. twitter.com/aaronpk).
If you do include the domain name, Quill will be able to show icons for recognized services next to the checkboxes.
Quill will check for your supported syndication targets when you sign in, but there is also a link on the new post screen to manually re-check if you'd like.