# HTTP API

FullView for NDI runs on port 9901, and listens on all interfaces. The following HTTP API routes are available.

### GET: /display/{displayNumber}/source/{name}

Changes the NDI source assigned to a given display, starting at display 0.

```
curl http://tractuspc1:9901/display/0/source/ALPHAVII%20%28Test%20Pattern%29
```

### GET: /displays

Gets a list of displays. Will eventually return display bounds and positions.

### GET: /debug

Returns performance information for the main renderer.

| Performance Metric | Description                                                                                                                                                                          |
| ------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `SdlEvents`        | The time it took in a given render cycle to process Windows-related UI events (mouseclicks, etc.). This should be < 1 msec.                                                          |
| `BlitRender`       | The time it took to render the scene before sending it to the GPU and waiting for vsync.                                                                                             |
| `RenderLoop`       | The total time, including `SdlEvents` and `BlitRender`, to render and present the scene. Should be close to 1000 / refresh rate (i.e. for a 60Hz refresh rate, this should be 16-17) |

{% hint style="warning" %}
If `BlitRender` is taking more than 16 msec, that means your PC cannot render the entire canvas within 16 milliseconds. When diagnosing performance issues, `BlitRender` is the most important number to interpret.
{% endhint %}


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```
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```

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