skills/remotion-best-practices/SKILL.md

---
name: remotion-best-practices
description: Router for all Remotion skills
version: 4.0.530
---

## Preserve user changes

Users may make edits in the code outside of the conversation.

If you detect a surprising change made in the meanwhile, don't overwrite it, assume it was intentional or ask for confirmation.

## Creating a video

If the user asks to make, create, or build a new video or composition, load [Create a new Remotion video](./remotion-create/REFERENCE.md), whether or not a Remotion project already exists.

## New project setup

If no Remotion project currently exists, load [Create a new Remotion project](./remotion-create/REFERENCE.md)

## React Markup Best Practices

If you are writing Remotion React Markup, load [Remotion Markup Best Practices](./remotion-markup/REFERENCE.md)

## Maps

For static maps, animated routes and markers, geographic explainers, Mapbox, MapLibre, MapTiler, GeoJSON, or 3D geographic flyovers, load [Remotion Maps](./remotion-maps/REFERENCE.md).

## Multimedia

For achieving multimedia tasks in the browser, such as trimming, cropping videos, or getting metadata from them, load [Remotion Multimedia](./remotion-multimedia/REFERENCE.md)

## Improving Interactivity

By structuring the Remotion markup well, we can allow users to interactively change things in the Studio and write back to code. If relevant: [Interactivity Best Practices](./remotion-interactivity/REFERENCE.md)

## Open the preview

If the user asks to "make" a video, "create" a video, etc.
Don't render the video by default unless they are very explicit. They want to instead see an interactive preview.
After creating or updating the video, start the preview server by default:

Always pass `--no-open` so the system browser is not opened:

```bash
npx remotion studio --no-open
```

This will start a long-running process and print the server URL for the preview.  
If the server is already started, it will print the URL.
Open the exact URL in the Codex in-app browser. If the in-app browser is not available, keep the preview server running and provide the URL to the user.
You can visit a specific composition by navigating to `/[composition-id]`, for example `http://localhost:3000/MapAnimation`.

:::note
The Studio supports WebMCP tools.
:::

### More options

To launch a project in Remotion Studio, open its exact local URL, or configure Studio CLI flags, load [Remotion Studio](./remotion-studio/REFERENCE.md).

## Render the video

Only render if the user is very explicit in asking for it.  
E.g. "Render the video", "Export", "Give me the MP4".

The preview also has a more intuitive rendering interface, so consider using it instead of the command line for rendering.

```
npx remotion render
```

For more options, see [Rendering](./remotion-render/REFERENCE.md).

For advanced rendering beyond simple `npx remotion render`, see: [Rendering Best Practices](./remotion-render/REFERENCE.md)

## Captions

When working with Captions, load [Remotion Captions](./remotion-captions/REFERENCE.md).

## Creating a SaaS, automation or application

Use the [Remotion SaaS skill](./remotion-saas/REFERENCE.md) for knowledge about Remotion-powered SaaS apps, such as `<Player>`, rendering on Lambda, Vercel, Cloudflare, via Express.js, client-side rendering, or for finding the right SaaS template.

## Looking up Remotion APIs and documentation

To find and read current Remotion documentation, load [Remotion Docs](./remotion-docs/REFERENCE.md).

## Upgrading

To upgrade Remotion, related packages, compatible Mediabunny packages, and installed Remotion Agent Skills, load [Remotion Upgrade](./remotion-upgrade/REFERENCE.md).


## Codex troubleshooting

When running inside Codex, first try starting the Remotion Studio without opening the system browser:

```bash
npx remotion studio --no-open
```

Only if that fails with file watcher limits such as `EMFILE: too many open files, watch`, retry with polling and without opening a browser from Codex:

```bash
npx remotion studio --no-open --webpack-poll 1000
```

If Studio still fails to start from Codex, ask the user to start it manually from their macOS Terminal and then continue using the already-running Studio. Sandbox errors while launching Chromium from Codex are likely caused by the Codex/macOS sandbox rather than the Remotion project.