> For the complete documentation index, see [llms.txt](https://docs.trmnl.com/go/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.trmnl.com/go/plugin-marketplace/plugin-screen-generation-flow.md).

# Plugin Screen Generation Flow

<figure><img src="/files/TcZ3G6rbyq1RnYmU4hny" alt=""><figcaption></figcaption></figure>

TRMNL generates a screen every X minutes, where X is the refresh frequency set by the user.

TRMNL generates screens by sending a POST request to the `plugin_markup_url` endpoint you specified during [Plugin Creation](/go/plugin-marketplace/plugin-creation.md). The request body will include the `user_uuid` (that particular user's plugin connection UUID) and some metadata. The request header contains an `authorization` key with the user's plugin connection `access_token`as the Bearer token. Here's an example of our server request:

```bash
curl -XPOST 'https://your-server.com/your-markup-url' \
-H 'Authorization: Bearer xxx' \
-H 'Content-Type: application/x-www-form-urlencoded' \
-d 'user_uuid=xx&trmnl=<metadata-object>'
```

The `trmnl` object in this payload may or may not be useful for your plugin, but includes the user-defined instance name, device dimensions, user timezone, and so on. Here's an example, subject to change:

```json
{
  "user": {
    "name": "Jim Bob",
    "first_name": "Jim",
    "last_name": "Bob",
    "locale": "en",
    "time_zone": "Eastern Time (US & Canada)",
    "time_zone_iana": "America/New_York",
    "utc_offset": -14400
  },
  "device": {
    "friendly_id": "XXXXXX",
    "percent_charged": 74.17,
    "wifi_strength": 50,
    "height": 480,
    "width": 800
  },
  "system": {
    "timestamp_utc": 1747596567
  },
  "plugin_settings": {
    "instance_name": "Upcoming Assignments"
  }
}
```

Your web server should respond with HTML inside root nodes named `markup`, `markup_quadrant`, and so on to satisfy each layout offered by TRMNL. This markup should include whatever values you want the user to see rendered on their screen.

{% hint style="success" %}
**Pro tip**: use the [Private Plugin](https://trmnl.com/plugin_settings/new?keyname=private_plugin) markup editor to develop the frontend of your plugin. This in-browser text editor supports live refresh and automatically applies the correct styling and JavaScript helpers to your markup.
{% endhint %}

TRMNL uses the markup in your server's response to generate an e-ink friendly image. If the user connecting your plugin created a "full screen" playlist item, TRMNL will leverage the HTML inside the `markup` node. If they connected your plugin as part of a left/right Mashup, TRMNL will look for HTML inside the `markup_half_vertical` node.

Here's an example of a valid server response:

```json
{
   "markup":"<div class=\"view view--full\"><div class=\"layout\"><div class=\"columns\"><div class=\"column\"><div class=\"markdown gap--large\"><span class=\"title\">Daily Scripture</span><div class=\"content-element content content--center\">Hello</div><span class=\"label label--underline mt-4\">World</span></div></div></div></div><div>",
   "markup_half_horizontal":"<div class=\"view view--half_horizontal\">Your content</div>",
   "markup_half_vertical":"<div class=\"view view--half_vertical\">Your content</div>",
   "markup_quadrant":"<div class=\"view view--quadrant\">Your content</div>",
   "shared":""
}
```

**Note:** in order for your plugin to be published in the TRMNL public marketplace, you must provide HTML for all available markup layouts. [View them here](https://help.trmnl.com/en/articles/10168132-mashups).