mythoi

a text-based game engine for interactive fiction, visual novels, muds, roguelikes, and beyond

our tools

Apollo: A Language Built for Text-Based Games

Built for Game Creators. Apollo is our custom programming language designed specifically for text-based games. While you can extend it with C++ if needed, Apollo handles the heavy lifting: managing game objects, running multiple things at once, and letting you test ideas quickly. Other languages make you build everything from scratch. Apollo gives you the tools game designers actually need, not generic programming features you'll never use.

Morpheus: The Engine That Runs Your Game

The Foundation. Morpheus is the runtime engine powering your game. It handles all the behind-the-scenes work: managing game objects, running multiple actions at once, saving and loading, networking for multiplayer. Inspired by classic systems from Bell Labs, it's built to be rock-solid and flexible. You focus on creating your game world; Morpheus handles the technical complexity.

Combinatory Categorial Grammar: Parsing Without the Pain

Commands That Just Work. Games like interactive fiction and MUDs need to understand player commands. Parsing is notoriously hard, and traditional tools (looking at you, Bison) produce cryptic black boxes. Our CCG parser is different: pick a pattern from our glossary, specify what happens, done. As simple as LPMUD's add_action, but modern. No grammar files, no lexer theory. As a game designer, focus on writing puzzles, not solving them.

Prometheus: Craft Text-Based Games Like Never Before

Write Stories That Live. Prometheus is your all-in-one IDE for text-based games, interactive fiction, and visual novels, featuring first-class mapping, a stellar code editor, and a built-in runtime console. Bring your branching narratives and immersive worlds to life with ease.

Alcibiades: Command-Line Power, Your Way

CLI Done Right. Love the terminal? Alcibiades lets you harness our entire ecosystem without a GUI. Write Apollo in your favorite editor with VS Code and Vim syntax/language support (we were going to provide Emacs too, but we got chased out of the room). Add JSON metadata, and run, test, or deploy with a single command.

Seamless Deployment: Web, Mobile, and Standalone

Deploy Anywhere. Single-player games run on web, iOS, Android, or as standalone apps. Multiplayer games can use SSH or WebSocket servers. Because it's all text-based, you can even deploy to Discord bots or Twitch chat. Our tutorials show you how for each genre. Whether you're shipping a roguelike or hosting a MUD, we've got you covered.

frequently asked questions

What is Mythoi?

Mythoi is a text-based game engine designed for interactive fiction, visual novels, MUDs (multi-user dungeons), and narrative-driven games. Leveraging Apollo (our custom language) and Morpheus (our runtime framework), it gives creators powerful tools to build immersive text-based experiences that run anywhere: from web browsers to mobile devices to standalone apps.

What kinds of games can I make with Mythoi?

Mythoi excels at text-based games: interactive fiction (like classic text adventures), visual novels, MUDs (multi-user dungeons), roguelikes, choice-driven narratives, and story-heavy RPGs. Our engine also supports rule-heavy simulations and game prototyping for tabletop RPG designers, CRPG developers, and anyone who wants to test game mechanics quickly.

Text-Based Game Engine, WTF?

Even without 3D graphics, games need object handling, concurrency, AI, pathfinding, networking, and more. We built a modular runtime that handles these fundamentals across all text-based genres. Extend it with dynamic modules like our CCG parser, SSH server, or WebSocket server. We provide working examples for popular genres. Whether you're building a roguelike, MUD, or visual novel, Mythoi handles the technical heavy lifting.

Wait, what's with the graphics mentions? I thought you were a text-based game engine?

Text-based doesn't mean text-only. Some MUDs use custom clients for graphics. Interactive fiction plus images equals visual novel. We'd be shortsighted to exclude these use cases. Our SSH support (not the zombified telnet protocol) enables separate communication channels for graphics, like MUD protocols do. Web deployments can use custom clients that integrate graphics seamlessly. Our visual novel framework includes examples.

Isn't this overkill for text-based games?

Games without 3D graphics still need solid infrastructure. Apollo and Morpheus are built for text-based games, interactive fiction, and visual novels, but also support advanced rule engineering and simulations. These genres are our sandbox for crafting immersive, rule-driven experiences with MUD-inspired flair.

Is Apollo a general-purpose language?

Yes, Apollo is a general-purpose language with prototype-based design, built-in concurrency, and automatic memory management. But its runtime is laser-focused on text-based games, interactive fiction, visual novels, and simulations. For TTRPG, CRPG, or JRPG designers, Apollo slashes playtesting time: build stories, combat systems, or NPCs in hours, not days. While Apollo can handle broader use cases, our runtime is optimized for game creation.

Do I need to use Prometheus to work with Apollo?

No, Prometheus is our tailored IDE for crafting text-based games with stellar mapping and editing tools. Prefer the terminal? Use Alcibiades for command-line workflows and import your Codex into Prometheus anytime for mapping support.

What documentation will Apollo offer?

Full EBNF/PEG grammar, detailed API docs, written and video tutorials. We're including a PDF with Apollo insights to supercharge AI-assisted coding. Full examples and tutorials for multiple genres: Interactive Fiction, MUDs, roguelikes, war games, and BBS doors.

What runtime environments does the Mythoi platform support?

Single-player games run on macOS, Windows, Linux, and FreeBSD with standalone apps supporting text, graphics, and audio. Deploy to the web with an Apollo Codex for instant, no-install gameplay. iOS and Android deliver seamless mobile experiences. Multiplayer games can be deployed as server/client over WebSocket or as a fully terminal-based offering with our SSH module.

Is Mythoi Z-Machine compatible?

Not anymore. Early builds supported Z-Machine output, but feedback showed fans of classic tools prefer open-source options. We're focused on propelling text-based games forward with a modern, high-performance runtime built for today's stories.

Is Mythoi Z-Machine compatible?

When will Mythoi products be available?

As of February 2026, we're gearing up for a Kickstarter! Check back soon for information.

Weren't you guys just doing an interactive fiction engine before?

Life happened. Personal and professional challenges last year pushed everything back about 12 months. But we made good use of the time. We'd always planned to build a full text-based game engine, but we were starting with just the interactive fiction use case. The delay gave us the opportunity to leverage our microkernel-based approach and expand the initial scope to include MUDs, roguelikes, and more from day one. Silver lining: you get a more complete engine at launch.

Where are you located?

Our principal is in Seattle. He's been working on these core systems for 30 years. He once rewrote Apollo's entire lexer/parser in an afternoon. When you know the problem space inside and out, you can move fast.

What is your future roadmap?

Check out our Kickstarter for future plans and roadmap details!

How do I stay in the loop?

Join our newsletter to catch exclusive updates on our soft launch! Follow us on X, our forum, or Discord. For press inquiries, email pr@mythoi.io.

Cool story bro, but I hate inheritance and boomer OOP garbage from the 90s

Apollo doesn't force inheritance or hierarchies. Use them if you want, or ignore them completely and use a flat object structure with ECS (Entity Component System). Apollo's inheritance is ephemeral: objects cloned from archetypes are property bags with an archetype association (like the flyweight pattern), which helps with serialization. Apollo's prototype-based design gives you flexibility: classic OOP, composition patterns, or something entirely different.

I want to see it!

Head on over to Kickstarter, we'll have lots to see there!

Are you all mad?

as hatters.