# Limitations of FiveM’s embedded browser (CEF)

> What does not work in FiveM NUI and loading screens: backdrop-filter, proprietary video codecs, window.open and normal links, alert/confirm dialogs, the clipboard API, and browser features that lag desktop Chrome — with a workaround for each.

Source: https://fam-tools.com/guides/fivem-nui-cef-limitations · FAM Tools · published 2026-09-11 · updated 2026-09-11 · about 9 min

**Short answer.** FiveM’s embedded Chromium lacks or restricts a few things desktop Chrome has: `backdrop-filter` is unreliable, proprietary codecs like H.264 cannot be relied on (use WebM), links and `window.open` do not open the player’s browser (use `window.invokeNative('openUrl', url)`), native dialogs like `alert` are not useful, and the async clipboard API often fails. It may also trail the latest Chrome release, so check features against its user agent.

## Key points

- No `backdrop-filter` — use semi-transparent solid colours.
- Video: WebM (VP9/VP8), not MP4/H.264.
- External links: `window.invokeNative('openUrl', url)` (http/https only).
- No `alert`/`confirm` — build your own dialogs.
- Clipboard: fall back to a hidden textarea + `document.execCommand('copy')`.

FiveM’s UI runs in the Chromium Embedded Framework, so it feels like building for Chrome — until something that works in your browser does nothing in game. Most surprises fall into a short list, and each has a simple workaround.

## The list

| Feature | In FiveM | Do this instead |
| --- | --- | --- |
| `backdrop-filter: blur()` | Unreliable, expensive | `background: rgba(10,10,14,0.85)` |
| MP4 / H.264 video | Unreliable | WebM with VP9 or VP8 |
| `<a href>` to a website | Navigates your UI away | `window.invokeNative('openUrl', url)` |
| `window.open` | No new browser window | `openUrl` as above |
| `alert` / `confirm` / `prompt` | Not useful in game | Your own modal |
| `navigator.clipboard` | Often fails | Hidden textarea + `execCommand('copy')` |
| Newest CSS/JS features | May be missing | Check `navigator.userAgent`, add fallbacks |

## Glass effects without backdrop-filter

Frosted glass panels are the most common casualty. Instead of blurring what is behind the panel, use a dark, mostly opaque background with a subtle border. It reads the same at game resolution and costs nothing.

*A panel that works in FiveM*

```css
.panel {
  background: rgba(12, 12, 16, 0.86);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 12px;
}
```

## Opening links

*links.js*

```js
function openExternal(url) {
  if (window.invokeNative) window.invokeNative('openUrl', url);
  else window.open(url, '_blank'); // normal browser during development
}
```

The same helper works on loading screens — see [interactive loading screens](https://fam-tools.com/guides/fivem-loading-screen-cursor-interactive).

## Copying to the clipboard

*copy.js*

```js
function copyText(text) {
  const el = document.createElement('textarea');
  el.value = text;
  el.style.position = 'fixed';
  el.style.opacity = '0';
  document.body.appendChild(el);
  el.select();
  document.execCommand('copy');
  el.remove();
}
```

`execCommand` is deprecated on the open web, but it is the approach that works reliably inside NUI for things like copying coordinates or a Discord invite.

## Checking what the browser supports

Open the NUI devtools and run `navigator.userAgent` to see the Chromium version your players have, or use `CSS.supports('property', 'value')` for a specific feature. Debugging steps: [NUI devtools](https://fam-tools.com/guides/fivem-nui-devtools-debugging).

## Questions

### Why does backdrop-filter not work in FiveM?

FiveM’s embedded Chromium does not render it reliably, and it is expensive. Use a semi-transparent solid background instead.

### Why does my MP4 not play in FiveM?

H.264 is a proprietary codec that FiveM’s Chromium cannot be relied on to decode. Convert to WebM (VP9).

### How do I open a website from NUI?

Call `window.invokeNative('openUrl', 'https://…')`; it opens the player’s default browser.

### How do I copy text to the clipboard in NUI?

Select a hidden textarea and call `document.execCommand('copy')`.

## Related

- https://fam-tools.com/guides/fivem-nui-basics
- https://fam-tools.com/guides/fivem-nui-performance
- https://fam-tools.com/guides/fivem-loading-screen-video-background
- https://fam-tools.com/guides/fivem-nui-devtools-debugging