Upload Game Asset Workflow

Overview

Upload arbitrary files (images, audio, 3D models) as hosted game assets via the REST API. Returns a permanent URL you can reference in your game HTML.

Prerequisites

• A game must already exist on the Remix platform (you need a game ID).
• The REMIX_API_KEY environment variable must be set.

Steps

1. Check for Existing Game ID

IMPORTANT: Do NOT create a new game without checking first.

Use gameId from task context or prior tool results when available.

Otherwise, read the nearest .remix-cli.json. Older projects may still use .remix-mcp.json. If either contains a gameId, reuse it.

Only if none of those sources contain a gameId should you follow the upload-game workflow to create one.

2. Upload the Asset

Send the file as multipart form data:

POST https://api.remix.gg/v1/games/{gameId}/assets
Authorization: Bearer $REMIX_API_KEY
Content-Type: multipart/form-data

Form fields:
  file       (required) — the binary file to upload
  assetName  (optional) — custom display name; defaults to the filename

Allowed extensions: .jpg, .jpeg, .png, .webp, .mp3, .wav, .hdr, .glb, .gltf

Max file size: 5 MB

Response:

{
  "success": true,
  "data": {
    "gameId": "...",
    "asset": {
      "url": "https://..."
    }
  }
}

Use data.asset.url as the hosted URL for the asset.

3. Use the URL in Game HTML

Reference the returned URL in your game code. Examples:

<img src="https://returned-asset-url.png" width="64" height="64" />

const img = new Image();
img.src = "https://returned-asset-url.png";
img.onload = () => ctx.drawImage(img, x, y, w, h);

const audio = new Audio("https://returned-asset-url.mp3");
audio.play();

4. (Optional) List All Assets

Retrieve all uploaded assets for a game:

GET https://api.remix.gg/v1/games/{gameId}/assets
Authorization: Bearer $REMIX_API_KEY

Tips

• Name files descriptively. Use clear filenames like player-idle.png or jump-sfx.mp3 -- the filename becomes the default asset name.
• Preload assets before gameplay. Wait for onload / canplaythrough events before starting the game loop to avoid missing assets.
• Stay under 5 MB per file. Compress images and audio before uploading. Use .webp for images and .mp3 for audio when possible.
• Repeat for each asset. Run through steps 2-3 for every file the game needs.