Asset Catalog API

The LoopLoop Asset Catalog is a searchable index of free game assets from across the web. Use it to find sprites, tilesets, audio, and other assets that match your game’s art direction.

Base URL

All endpoints below are relative to the platform API:

https://api.looploop.dev

For example, GET /api/asset-packs means GET https://api.looploop.dev/api/asset-packs.

Note: looploop.dev (without the api. subdomain) serves developer documentation, not the API. Always use api.looploop.dev for API calls.

Overview

The catalog indexes asset packs from Kenney, OpenGameArt, itch.io, GitHub, and LoopLoop-hosted creators. Every pack includes style metadata — art style, perspective, resolution, palette, and a consistency score — so you can filter for packs that fit your game.

Key concepts:

Reference-only by default: Metadata + source link + sample images. Full files are stored only for promoted packs.
License tiers: redistributable (CC0, MIT, CC-BY, etc.) vs reference_only (NC, ND, ambiguous)
Download types: agent (auto-downloadable), manual, donate, paid
Style analysis: Each pack is scored across 7 aspects (shading, edges, surface detail, color, form language, material rendering, overall feel) with a consistency score

Browse Packs

`GET /api/asset-packs`

Browse and search the catalog. No auth required.

Query parameters:

Param	Type	Description
`q`	string	Full-text search across name, description, tags, art style, style description, author, perspective, resolution, asset item types/categories, and source names. Supports stemming (e.g. “pirates” matches “pirate”) and compound word fragmentation (e.g. “sailboat” matches packs tagged “boat” or “sail”). Multi-word queries use OR logic with relevance ranking.
`packType`	string	Pack type filter: `sprites`, `interface`, `models`, `audio`, `fonts`, `icon-fonts`, `kits`
`tags`	string	Comma-separated tag filter
`category`	string	Asset category filter (free-form, e.g. “characters”, “vehicles”, “terrain”)
`artStyle`	string	Art style filter (free-form tags, e.g. “soft-shading”, “low-poly”, “cartoonish”)
`perspective`	string	Perspective filter (top-down, side-scroll, isometric, etc.)
`resolution`	string	Resolution filter (16x16, 32x32, etc.)
`engine`	string	Engine compatibility filter
`source`	string	Source filter (kenney, opengameart, itch, github)
`sort`	string	Sort order: `downloads` (default), `newest`, `consistency`
`limit`	number	Max results (default 20, max 100)
`offset`	number	Pagination offset

Response:

{
  "packs": [
    {
      "id": "uuid",
      "slug": "kenney-1-bit-pack",
      "name": "Kenney 1-Bit Pack",
      "description": "Over 1000 monochrome 1-bit style sprites and tiles",
      "license": "CC0-1.0",
      "tags": ["1-bit", "monochrome", "pixel-art"],
      "sourceUrl": "https://kenney.nl/assets/1-bit-pack",
      "downloadType": "agent",
      "author": "Kenney",
      "licenseTier": "redistributable",
      "packType": "sprites",
      "artStyle": "soft-shading, chunky-geometry, bright-color-palette",
      "perspective": "isometric",
      "resolution": "HD",
      "styleDescription": "The art style combines low-poly, hand-painted textures with...",
      "thumbnailUrl": "/cdn/asset-packs/kenney-1-bit-pack/thumbnail.png",
      "sampleUrls": ["/cdn/asset-packs/kenney-1-bit-pack/samples/sample-001.png"],
      "assetCount": 1024,
      "downloadCount": 150
    }
  ],
  "total": 342,
  "limit": 20,
  "offset": 0
}

Pack Details

`GET /api/asset-packs/:slug`

Full pack details including all asset items and style analysis.

Response:

{
  "pack": {
    "id": "uuid",
    "slug": "kenney-1-bit-pack",
    "name": "Kenney 1-Bit Pack",
    "...": "all pack fields",
    "styleAnalysis": {
      "artStyle": "soft-shading, chunky-geometry, bright-color-palette",
      "synthesis": "The art style combines low-poly hand-painted textures with...",
      "styleTags": ["soft-shading", "chunky-geometry", "bright-color-palette"],
      "aspects": {
        "shading": "Shadows use soft gradients with smooth light transitions...",
        "edges": "Rounded, beveled edges enhance a friendly appearance...",
        "surfaceDetail": "Minimal surface detail with broad color patches...",
        "color": "Vibrant, saturated palette with smooth transitions...",
        "formLanguage": "Chunky, inflated proportions with exaggerated scale...",
        "materialRendering": "Materials distinguished by color, not reflections...",
        "overallFeel": "Playful, approachable style reminiscent of casual mobile games..."
      },
      "perspective": "isometric",
      "resolution": "HD",
      "palette": ["#3A3A3A", "#FFB873", "#6DD3CE", "#A4B9EF", "#7E7868"]
    }
  },
  "assets": [
    {
      "id": "uuid",
      "assetId": "knight-idle",
      "type": "sprite",
      "category": "characters",
      "path": "Tilemap/Characters/knight_idle.png",
      "description": "Knight character idle pose, 16x16 monochrome",
      "tags": ["knight", "character", "idle"],
      "metadata": { "width": 16, "height": 16 },
      "downloadUrl": "https://kenney.nl/assets/1-bit-pack"
    }
  ]
}

Structured Search (for Agents)

`POST /api/asset-packs/search`

Designed for AI agents to find assets matching specific needs and style requirements. Returns ranked results with match scores.

Request body:

{
  "needs": [
    { "type": "spritesheet", "category": "enemies", "tags": ["undead"], "minFrames": 4 },
    { "type": "tileset", "category": "environment", "tags": ["dungeon"] },
    { "type": "audio", "category": "sfx", "tags": ["combat"] }
  ],
  "style": {
    "artStyle": "pixel-art",
    "perspective": "top-down",
    "resolution": "16x16"
  },
  "packType": "sprites",
  "limit": 10
}

Response:

{
  "results": [
    {
      "score": 72.5,
      "pack": {
        "slug": "kenney-1-bit-pack",
        "name": "Kenney 1-Bit Pack",
        "artStyle": "pixel-art",
        "styleConsistencyScore": 62,
        "downloadType": "agent",
        "attributionRequired": false
      },
      "matchingAssets": [
        {
          "assetId": "skeleton-walk",
          "type": "spritesheet",
          "category": "enemies",
          "path": "Spritesheets/skeleton_walk.png",
          "downloadUrl": "..."
        }
      ]
    }
  ],
  "total": 5
}

Download Assets

`POST /api/asset-packs/:slug/download`

Record a download event and get download URLs. For promoted packs, returns CDN URLs. For non-promoted packs, returns the source download URL.

Request body:

{
  "assetIds": ["skeleton-walk", "dungeon-tileset"],
  "gameSlug": "my-game",
  "gameId": "optional-game-uuid"
}

Response:

{
  "packSlug": "kenney-1-bit-pack",
  "packName": "Kenney 1-Bit Pack",
  "downloadType": "agent",
  "licenseTier": "redistributable",
  "attributionRequired": false,
  "source": "external",
  "sourceDownloadUrl": "https://kenney.nl/content/3-Assets/kenney_1-bit-pack.zip",
  "assets": [
    {
      "assetId": "skeleton-walk",
      "type": "spritesheet",
      "category": "enemies",
      "path": "Spritesheets/skeleton_walk.png",
      "downloadUrl": "https://kenney.nl/content/3-Assets/kenney_1-bit-pack.zip"
    }
  ]
}

Single Asset

`GET /api/asset-packs/:slug/assets/:assetId`

Get metadata and download URL for a single asset.

Per-Game Asset Tracking

Track which assets each game has downloaded, which are actively used in code, and generate attribution/credits lists. All data is stored server-side in D1.

`POST /api/games/:slug/assets/track`

Record assets downloaded into a game. Called automatically by the downloadPackAssets() client when gameSlug is provided, or manually by agents after acquiring files.

Request body:

{
  "packSlug": "kenney-1-bit-pack",
  "assets": [
    {
      "assetId": "skeleton-walk",
      "localPath": "public/assets/packs/kenney-1-bit-pack/Spritesheets/skeleton_walk.png",
      "category": "enemies"
    }
  ]
}

Response:

{ "tracked": 1 }

`PUT /api/games/:slug/assets/mark-used`

Mark tracked assets as actively used in game code. Agents call this after wiring an asset into a config file, source import, or other reference. Also supports marking assets as removed when they are no longer referenced.

Request body:

{
  "assets": [
    {
      "assetId": "skeleton-walk",
      "referencedBy": ["src/scenes/GameScene.ts", "config/enemies.json"]
    }
  ]
}

To mark an asset as removed:

{
  "assets": [
    {
      "assetId": "skeleton-walk",
      "referencedBy": [],
      "status": "removed"
    }
  ]
}

Response:

{ "updated": 1 }

`GET /api/games/:slug/assets`

List all tracked assets for a game. Joins with asset_packs to include license info.

Query parameters:

Param	Type	Description
`status`	string	Filter by status: `downloaded`, `in_use`, or `removed`

Response:

{
  "assets": [
    {
      "assetId": "skeleton-walk",
      "localPath": "public/assets/packs/kenney-1-bit-pack/Spritesheets/skeleton_walk.png",
      "status": "in_use",
      "referencedBy": ["src/scenes/GameScene.ts", "config/enemies.json"],
      "downloadedAt": "2026-03-20T12:00:00Z",
      "pack": {
        "slug": "kenney-1-bit-pack",
        "name": "Kenney 1-Bit Pack",
        "license": "CC0-1.0",
        "licenseTier": "redistributable",
        "attributionRequired": false,
        "attributionText": null,
        "author": "Kenney",
        "authorUrl": "https://kenney.nl",
        "sourceUrl": "https://kenney.nl/assets/1-bit-pack"
      }
    }
  ]
}

`GET /api/games/:slug/credits`

Generate an attribution/credits list for all in_use assets in a game, grouped by pack.

Query parameters:

Param	Type	Description
`all`	string	Set to `true` to include all packs (including those that don’t require attribution like CC0). Default: only packs where `attributionRequired` is true.

Response:

{
  "gameSlug": "my-game",
  "generatedAt": "2026-03-20T12:00:00Z",
  "packs": [
    {
      "name": "Kenney Tiny Town",
      "author": "Kenney",
      "authorUrl": "https://kenney.nl",
      "license": "CC-BY-4.0",
      "sourceUrl": "https://kenney.nl/assets/tiny-town",
      "attributionText": "Kenney (https://kenney.nl) — CC-BY-4.0",
      "assetsUsed": ["tiles/grass.png", "tiles/road.png", "buildings/house.png"]
    }
  ],
  "markdown": "## Third-Party Assets\n\n**Kenney Tiny Town** by Kenney (https://kenney.nl) -- CC-BY-4.0\nSource: https://kenney.nl/assets/tiny-town\nCredit: Kenney (https://kenney.nl) — CC-BY-4.0\nAssets: tiles/grass.png, tiles/road.png, buildings/house.png\n"
}

The markdown field is ready to embed in a credits screen or write to an ATTRIBUTION.md file.

Usage Guide

Search → Download → Track → Credit

Search the catalog via POST /api/asset-packs/search with your style constraints and asset needs
Evaluate results — check styleDescription, styleAnalysis.aspects, sample images, and score
Download via POST /api/asset-packs/:slug/download with the asset IDs you want — pass gameSlug to link the download to a game
Track — the downloadPackAssets() client helper auto-calls POST /api/games/:slug/assets/track; or call it manually
Mark used — after wiring an asset into game code, call PUT /api/games/:slug/assets/mark-used with the source files that reference it
Generate credits — call GET /api/games/:slug/credits before shipping to get a formatted attribution list

License compliance

Packs with downloadType: 'agent' can be fetched automatically
Packs with manual, donate, or paid download types appear in search results but require human action to acquire
Only redistributable tier packs should be downloaded into games; reference_only and unknown packs are for inspiration only
For packs where attributionRequired is true, add the pack’s attributionText to your credits
Call GET /api/games/:slug/credits to auto-generate the full attribution list from tracked usage
When removing an asset, call mark-used with status: "removed" to preserve audit history