# Fifth Door

> Fifth Door hosts static web games and gives them players. Creators build with any editor and coding agent, publish with the Fifth Door MCP server, and can use the Platform SDK for play-time services: identity, saved progress, shared records, multiplayer, in-game LLM calls, daily puzzles, notifications. Hosted agents that cannot run MCP create games with the Partner API.

## Play

- [Discover](https://play.fifthdoor.com/discover): browse and play published games in the browser
- [Make a game](https://play.fifthdoor.com/create): describe a game in plain words and play it

## Docs

- [Build for Fifth Door](https://play.fifthdoor.com/docs): overview and quickstart
- [Publish from your editor](https://play.fifthdoor.com/docs/mcp.md): install the MCP server, sign in, publish, and every tool
- [Partner API](https://play.fifthdoor.com/docs/partners.md): REST for hosted agents (Muse first): OAuth sign-in, create from a prompt, poll, iterate
- [Platform SDK docs index](https://api.beta.fifthdoor.com/api/platform/sdk/latest/index.json): the current release's reference, capability topics, and guides as JSON; each entry's doc is at https://api.beta.fifthdoor.com/api/platform/sdk/latest/docs/<id> as { version, topic, markdown }
- [Platform SDK reference](https://api.beta.fifthdoor.com/api/platform/sdk/latest/docs/platform-sdk)
- [Setting up a project](https://api.beta.fifthdoor.com/api/platform/sdk/latest/docs/setup): adding the SDK to a project outside Studio

## Blog

- [AI Game Jams: How to Enter One with a Game You Made with AI](https://play.fifthdoor.com/blog/ai-game-jam): What an AI game jam is, how to check if a jam allows AI, how to scope a jam game, and how to enter the Fifth Door weekly jam from your editor.
- [How to Make an RPG with AI (Start Small, Ship It)](https://play.fifthdoor.com/blog/make-an-rpg-with-ai): Make an RPG with AI by scoping small: four RPG prompts, the order to build systems, AI-driven NPC dialogue, saves, and art on Fifth Door.
- [AI Games on Mobile: Browser Play + Android App Guide](https://play.fifthdoor.com/blog/ai-games-mobile-browser): Play AI games on mobile via Fifth Door: Android app on Google Play, or mobile browser Discover on iPhone and Android. Not a generic best-mobile-games list.
- [How to Make a Quiz or Trivia Game with AI](https://play.fifthdoor.com/blog/make-a-quiz-game-with-ai): Make a quiz or trivia game with AI: formats that play well, five copyable prompts, how to fact-check questions, and adding leaderboards or rooms on Fifth Door.
- [How to Add a Leaderboard to a Browser Game Without a Backend](https://play.fifthdoor.com/blog/add-leaderboard-to-browser-game): Add a leaderboard to a browser game without running a server. Daily and friends boards, ranked reads, and the prompt to give your agent on Fifth Door.
- [How to Make a Game with Claude Code (and Put It Online)](https://play.fifthdoor.com/blog/make-a-game-with-claude-code): Make a game with Claude Code: the first prompt, a play-and-fix loop, art and sound, and publishing to a public link with the Fifth Door MCP server.
- [Free AI Games Online with No Download (Browser Play Guide)](https://play.fifthdoor.com/blog/free-ai-games-online-no-download): Play free AI games online with no download via Fifth Door Discover in your browser. Android users can also install the Play Store app. Instant play FAQ.
- [AI Game Ideas: 40 Small Games You Can Make with AI Today](https://play.fifthdoor.com/blog/ai-game-ideas): 40 AI game ideas scoped to build in one session: arcade, puzzle, daily, platformer, story, party, and games that use AI or the camera while you play.
- [How to Make a Daily Puzzle Game Like Wordle with AI](https://play.fifthdoor.com/blog/make-a-daily-puzzle-game-with-ai): Make a daily puzzle game like Wordle with AI: the five rules of a good daily, copyable word, number, and trivia prompts, and same-puzzle-for-everyone on Fifth Door.
- [How to Make a Platformer Game with AI (Prompts That Feel Good)](https://play.fifthdoor.com/blog/make-a-platformer-with-ai): Make a platformer game with AI: what to put in the prompt, five copyable platformer prompts, follow-ups that fix floaty jumps, and how to share it on Fifth Door.
- [How to Publish a Vibe-Coded Game (Claude Code, Cursor, Codex)](https://play.fifthdoor.com/blog/publish-vibe-coded-game): Get a game built with Claude Code, Cursor, or Codex off localhost. Compare hosting options and publish to Fifth Door from your editor with the MCP server.
- [Best AI Browser Games 2026 (Playable Games, Not Chat RPGs)](https://play.fifthdoor.com/blog/best-ai-browser-games-2026): Best AI browser games in 2026, scoped to playable AI-made games. Use Fifth Door Discover shelves and criteria lists. Android app available; iPhone via browser.
- [How to Make a Multiplayer Game with AI (Friends Join by Link)](https://play.fifthdoor.com/blog/make-a-multiplayer-game-with-ai): Make a multiplayer game with AI by describing how players join, take turns, and win. Fifth Door hosts rooms, invites, and leaderboards. Prompts and a test plan.
- [Rosebud AI Alternatives for Prompt-to-Playable Games](https://play.fifthdoor.com/blog/rosebud-ai-alternatives): Fair look at Rosebud AI alternatives for creators who want prompt-to-playable browser games, sharing, and discovery. Includes how Fifth Door compares on create + Discover.
- [Best Prompts for an AI Game Generator (Examples That Play)](https://play.fifthdoor.com/blog/ai-game-generator-prompts): Best prompts for an AI game generator: genre, goal, action, feel, and one constraint. Copyable examples for arcade, puzzle, adventure, and party-style games.
- [Infinite AI Arcade: How to Discover Endless AI-Made Games](https://play.fifthdoor.com/blog/infinite-ai-arcade): Looking for an infinite AI arcade? Browse Fifth Door Discover (Featured, For You, Top, Daily New) in browser or the Android app. Habit guide, not fake counts.
- [No-Code AI Game Creator: Make Playable Games from Prompts](https://play.fifthdoor.com/blog/no-code-ai-game-creator): Use a no-code AI game creator to describe an idea and get a playable browser game. Learn the Fifth Door create loop, templates, sharing, and Discover.
- [AI Game Maker vs Game Engine: Which Should You Use?](https://play.fifthdoor.com/blog/ai-game-maker-vs-game-engine): AI game maker vs game engine explained for creators: when to use prompt-to-playable tools like Fifth Door, and when Unity or Godot still win.
- [Best AI Game Makers 2026: How to Choose (Prompt to Playable)](https://play.fifthdoor.com/blog/best-ai-game-makers-2026): A criteria-based guide to AI game makers in 2026: prompt-to-playable, share, and discovery. Includes Fifth Door's create + Discover angle without fake rankings.
- [Free AI Game Maker Online: What to Look For in 2026](https://play.fifthdoor.com/blog/free-ai-game-maker): Looking for a free AI game maker online? Learn what "free" usually covers, how to evaluate hosted prompt-to-playable tools, and how to start creating on Fifth Door.
- [AI-Generated Browser Games to Play (Free, Instant Sessions)](https://play.fifthdoor.com/blog/ai-generated-browser-games-to-play): Play AI-generated browser games on Fifth Door Discover: Featured, For You, Top, and Daily New. Open in your browser, or install the Android app. No fake rankings.
- [What Is an AI Game Generator? (Definition for Creators)](https://play.fifthdoor.com/blog/what-is-an-ai-game-generator): An AI game generator turns a plain-language idea into a playable game. Learn what it is, what it is not, and how Fifth Door fits the prompt-to-playable category.
- [How to Turn a Text Prompt into a Playable Game](https://play.fifthdoor.com/blog/text-prompt-to-playable-game): Turn a text prompt into a playable browser game: write a clear idea, let an AI agent build it, playtest, iterate, and share a link on Fifth Door.
- [How to Make a Game with AI Without Coding (Prompt to Playable)](https://play.fifthdoor.com/blog/make-a-game-with-ai-without-coding): Learn how to make a game with AI on Fifth Door: describe an idea, play it in the browser, share a link, and keep creating on Discover.

## Packages

- [@fifth-door/mcp](https://www.npmjs.com/package/@fifth-door/mcp)
- [@fifth-door/platform-sdk](https://www.npmjs.com/package/@fifth-door/platform-sdk)