Unity Framework — Coming Soon

Build your
monster-catching
game.

OpenMon is the complete Unity framework for Pokémon-like games — battle systems, stat engine, monster roster, and more. Build from scratch or bring your existing project. Ship commercially, on any platform, fully yours.

The Problem

Building a Pokémon-like game from scratch is brutal.

Battle systems. Type matchups. Stat formulas. Wild encounters. Evolution logic. UI. Save systems. That’s months of engineering before you write a single line of your actual game.


The Solution

OpenMon ships all of that ready to use.

Drop OpenMon into Unity. Your framework is ready. Design your world, create your monsters, write your story — and ship a game that’s entirely, commercially yours.

Everything You Need

One framework. Full creative control.

Complete Battle Engine

Turn-based battles, type matchups, stat formulas, moves, abilities, status effects — all built-in and ready to customize.

Full Game Systems

Wild encounters, trainer battles, evolution, items, Pokédex-style registry, save system, and overworld — all included.

Commercially Yours

Built for original IP from the ground up. Design your assets, own your game, publish on Steam, Unity, or Epic — no restrictions.

Unity Powered

Leverage Unity’s engine, asset pipeline, and cross-platform deployment. Professional-grade tools, by developers for developers.

How It Works

From idea to shipped game, in three steps.

1

Set Up

Drop OpenMon into your Unity project. The full framework is ready — battles, encounters, evolution, UI, and more out of the box.

2

Build Your World

Design your monsters, maps, moves, and story using OpenMon’s data-driven tools. No engine programming required.

3

Ship It

Your game, your assets, your IP. Publish on Steam, the Unity Asset Store, or the Epic Games Store — with zero restrictions.

Demo

See It in Action

A look at the full framework running inside Unity.

Bonus Feature

Already have a Pokémon Essentials project?

OpenMon imports PE projects directly. Your maps, events, mechanics, stats, and levels transfer automatically — zero manual porting. Swap in original assets and you’re ready to publish commercially.

Your World

Original monsters.
Zero copyright risk.

Design your own roster of monsters — inspired by the genre, owned entirely by you. OpenMon handles battle mechanics, stat systems, and animations. You just create.

Original monster design — OpenMon creature capture game engine for Unity

Front

Custom monster sprite — fakemon creator and monster taming engine for Unity games

Profile

Example original monster — not affiliated with any existing IP

Coming to Every Major Platform

OpenMon will launch on the Unity Asset Store and Fab by Epic Games. We’re applying for an Epic MegaGrant to bring the full framework to Unreal Engine.

Unity Asset Store
Fab by Epic Games
Epic MegaGrant Applicant

Editions

Five editions. One engine.

Every edition ships the full framework. Each step up unlocks a real capability — not a licence clause.

Starter
Learn the engine with a free account on openmon.io. Free games only: commercial use needs a paid edition.
Freewith an account · only on openmon.io
  • Full framework: battle, stats, monsters, grid worlds, save
  • Visual scripting (runtime + editor)
  • Up to 77 monsters, 301 moves and 74 abilities (everything its demo uses)
  • Starter demo: 77 species, 301 moves
  • Remove the OpenMon splash screen
  • No in-game watermark
  • Online & multiplayer (Nakama)
  • Pokémon Essentials importer
  • Full C# source
  • Private git repo access
  • Continuous updates, straight from main
  • Experimental features before release
  • Cartridge importers (HGSS, FireRed, B/W)
Most popular
Indie
Ship a commercial single-player game, your brand only. Bring your Essentials project with you.
$99one-time
  • Full framework: battle, stats, monsters, grid worlds, save
  • Visual scripting (runtime + editor)
  • Unlimited monsters
  • MIT Licensed Demo (separate download)
  • Remove the OpenMon splash screen
  • No in-game watermark
  • Online & multiplayer (Nakama)
  • Pokémon Essentials importer
  • Full C# source
  • Private git repo access
  • Continuous updates, straight from main
  • Experimental features before release
  • Cartridge importers (HGSS, FireRed, B/W)
Pro
Multiplayer, trading and online battles.
$199one-time

On sale once it passes its release gate.

  • Full framework: battle, stats, monsters, grid worlds, save
  • Visual scripting (runtime + editor)
  • Unlimited monsters
  • MIT Licensed Demo (separate download)
  • Remove the OpenMon splash screen
  • No in-game watermark
  • Online & multiplayer (Nakama)
  • Pokémon Essentials importer
  • Full C# source
  • Private git repo access
  • Continuous updates, straight from main
  • Experimental features before release
  • Cartridge importers (HGSS, FireRed, B/W)
Source
Studios and plugin authors who need the code.
$399one-time

Rises to $499 after 25 reviews averaging 4.2.

  • Full framework: battle, stats, monsters, grid worlds, save
  • Visual scripting (runtime + editor)
  • Unlimited monsters
  • MIT Licensed Demo (separate download)
  • Remove the OpenMon splash screen
  • No in-game watermark
  • Online & multiplayer (Nakama)
  • Pokémon Essentials importer
  • Full C# source
  • Private git repo access
  • Continuous updates, straight from main
  • Experimental features before release
  • Cartridge importers (HGSS, FireRed, B/W)
Studio
Source plus the repo: every commit, every experiment.
$59912 months included · then $199/year
  • Full framework: battle, stats, monsters, grid worlds, save
  • Visual scripting (runtime + editor)
  • Unlimited monsters
  • MIT Licensed Demo (separate download)
  • Remove the OpenMon splash screen
  • No in-game watermark
  • Online & multiplayer (Nakama)
  • Pokémon Essentials importer
  • Full C# source
  • Private git repo access
  • Continuous updates, straight from main
  • Experimental features before release
  • Cartridge importers (HGSS, FireRed, B/W)
FeatureStarterFreeIndie$99Pro$199Source$399Studio$599 + $199/yr
Full framework: battle, stats, monsters, grid worlds, save✓✓✓✓✓
Visual scripting (runtime + editor)✓✓✓✓✓
Unlimited monsters77✓✓✓✓
MIT Licensed Demo (separate download)77 / 301✓✓✓✓
Remove the OpenMon splash screen✗✓✓✓✓
No in-game watermark✗✓✓✓✓
Online & multiplayer (Nakama)✗✗✓✓✓
Pokémon Essentials importer✗✓✓✓✓
Full C# source✗✗✗✓✓
Private git repo access✗✗✗✗✓
Continuous updates, straight from main✗✗✗✗✓
Experimental features before release✗✗✗✗✓
Cartridge importers (HGSS, FireRed, B/W)✗✗✗✗✓
Or by subscriptionGet OpenMon with Yakuza.sh — the AI copilot for Unity.Every paid Yakuza.sh plan includes an edition: Indie → Indie, Studio → Pro, Team → Source, Enterprise → Studio. Rent-to-own: after 6 months in a row on Indie, or 3 on Studio or Team, that version is yours to keep forever; updates continue while your plan is active.See Yakuza.sh plans →

Start with any edition. Upgrade later by paying the difference.

Indie and every edition above it let you sell your game with no royalties; Starter is for evaluation and non-commercial use. The full demo is the MIT Licensed Demo, a separate download from Indie up. Yakuza.sh subscribers get an edition bundled with their plan — see yakuza.sh.

Get Early Access

Be the first to know when OpenMon launches. No spam — just the important stuff.

Frequently Asked Questions

Everything you need to know about building monster-catching games with OpenMon.

Can I use OpenMon to make a monster-catching game?

Absolutely. OpenMon is a complete monster capture engine built for Unity that gives you everything needed to create a game in the style of classic creature-catching RPGs. It ships with a fully featured turn-based battle system, 668+ moves, type matchups, stat formulas, wild encounters, evolution logic, a save system, and grid-based overworld navigation. Whether you want to build a single-player adventure or a full monster-catching MMO, OpenMon provides the framework so you can focus on your creative vision instead of re-engineering core systems from scratch.

How does OpenMon compare to Pokemon Essentials?

Pokemon Essentials is a popular RPG Maker XP toolkit, but it ties your project to Ruby scripting, 2D-only rendering, and copyrighted assets that prevent commercial release. OpenMon is the leading Pokemon Essentials alternative built on Unity 6, giving you access to modern 2D and 3D rendering, C# scripting, cross-platform deployment, and a professional asset pipeline. OpenMon even includes an importer that can convert your existing Pokemon Essentials project directly into the Unity framework, preserving your maps, events, stats, and mechanics. If you have ever searched for a way to take your fan game to the next level, OpenMon is that bridge.

Can I publish my game commercially with OpenMon?

Yes, that is precisely what OpenMon was designed for. Unlike fan game tools that rely on copyrighted IP, OpenMon is built for original IP from the ground up. You design your own monsters, your own world, and your own story. The game you ship is entirely yours. Publish on Steam, the Epic Games Store, console marketplaces, mobile stores, or anywhere else Unity deploys to. Commercial release needs the Indie edition or above; Starter is for evaluation and non-commercial use. There are no royalties, no revenue shares, and no restrictions on commercial distribution. If you want to sell a monster-catching game legally, OpenMon is the framework that makes it possible.

Does OpenMon work with Unreal Engine?

OpenMon is currently built for Unity 6 (URP), which is the most widely used game engine in the indie space. However, we are actively applying for an Epic MegaGrant to fund a full Unreal Engine port. If you are searching for a monster-catching game engine for Unreal, join our waitlist to be notified when the UE5 version launches. In the meantime, Unity gives you access to every major platform including PC, console, mobile, and web.

What is the difference between OpenMon and RPG Maker?

RPG Maker is a general-purpose 2D RPG tool that requires extensive scripting and plugins to support creature-catching mechanics. OpenMon is purpose-built for the monster-catching genre, running on Unity with professional-grade tools. You get a complete turn-based battle system, monster roster management, a grid-based tile engine, evolution chains, abilities, type matchups, a trainer AI system, and a visual scripting tool for NPC behavior, all out of the box. If RPG Maker is a blank canvas, OpenMon is a fully assembled monster game framework where you design the content and ship a polished product.

Can I import my Pokemon Essentials project into Unity?

Yes. OpenMon includes a dedicated Pokemon Essentials importer that reads PE v20, v21, and v21.1 project files and converts them into Unity-native data. Your maps, events, trainer configurations, wild encounter tables, move definitions, and stat structures all transfer automatically. Once imported, you swap in original monster designs and assets to replace any copyrighted material, and your project is ready for commercial release. This is the fastest path from a Pokemon Essentials fan game to a fully original, publishable title on Unity.

Does OpenMon support multiplayer or MMO?

Yes. OpenMon includes an optional online layer powered by Nakama, an open-source multiplayer server. This gives you real-time world synchronization, player-vs-player battles, social features, a virtual economy, live ops, and persistent cloud saves. If you have ever dreamed of building your own monster-catching MMO or a multiplayer experience similar to PokeMMO, OpenMon provides the complete networking infrastructure so you can focus on game design instead of server engineering. The online module is fully optional, so single-player-only games work with zero networking overhead.

Is OpenMon open source?

OpenMon will offer options including full source access, so you can extend, modify, or learn from the engine internals. The documentation at openmon.io/docs Editions is freely available and covers the full architecture, API reference, guides for creating monsters, building worlds, and configuring battles. OpenMon will be distributed through the Unity Asset Store and Fab by Epic Games. Join the waitlist to be notified when it launches.

Can I convert my Pokemon Essentials fan game to sell on Steam?

Yes. OpenMon includes a one-click importer for Pokemon Essentials v20, v21, and v21.1 projects. It converts your maps, events, trainers, encounters, moves, and stats into Unity-native data automatically. Once imported, you replace the copyrighted Pokemon assets with your own original monster designs, art, and names. The result is a fully original game that you own and can sell commercially on Steam, the Epic Games Store, consoles, or mobile. Developers behind projects like Pokemon Reborn, Insurgence, Infinite Fusion, and Unbreakable Ties face the same problem — years of work with no path to market. OpenMon is that path.

Is OpenMon better than making a game in RPG Maker?

RPG Maker is a general-purpose 2D RPG tool that requires extensive scripting and community plugins for any monster-catching mechanics. OpenMon is purpose-built for the monster-catching genre, running on Unity 6 with professional-grade tools. You get a complete turn-based battle system with 668+ moves, type matchups, stat formulas, abilities, evolution chains, a grid-based tile engine, visual scripting for NPC events, and an optional online multiplayer layer — all out of the box. RPG Maker also limits you to Windows-only distribution, while Unity deploys to PC, Mac, Linux, mobile, web, and consoles. If you are building a monster-catching game specifically, OpenMon saves you 12-18 months of engineering.

What monster-catching games have been funded on Kickstarter?

The monster-catching genre is thriving on Kickstarter. Elestrals Awakened raised $1.4M in 2025, making it the most-funded monster catcher of the year. Monsterpatch, a cozy monster collector, hit 1,500% of its funding goal. Tomo: Endless Blue brought open-world voxel exploration to the genre and found its audience immediately. On the commercial side, Temtem built a $500M+ franchise, Palworld earned $400M+ in 2024, Coromon succeeded as a small indie on Steam, and Cassette Beasts was critically acclaimed. OpenMon gives you the same production-grade foundation these games were built on — battle systems, monster databases, grid worlds, save systems, and multiplayer — ready to use on day one.

Where does OpenMon come from?

OpenMon grew out of the remains of YAPU (Yet Another Pokémon Unity), the MIT-licensed project Varguiniano published on GitHub in December 2024 as a learning resource. YAPU already had a solid base: the first three generations of creatures, single and double battles, graph-based NPCs and events, a day-night cycle, weather, breeding, quests and multiple save files. I spent two years finishing it and turning it into a commercial engine. These are the improvements I made:

New features

  • Pokémon Essentials importer for v20, v21 and v21.1 projects: maps, events, trainers, wild encounters, moves and stats, proven end to end against a complete v21.1 project with 898 species.
  • Cartridge importers for FireRed, HeartGold/SoulSilver and Black/White, in the Studio edition.
  • Online mode on a Nakama server: accounts, a shared world, battles, rosters, economy, social features, housing, persistence and server-side anti-cheat. Multiplayer was on YAPU's roadmap.
  • Battle AI trained with reinforcement learning (Unity ML-Agents), next to the classic AIs. It was on YAPU's roadmap too.
  • OpenMon Hub, an editor window to set up the project and reach every tool.

Paid libraries replaced, libraries rewritten

  • Odin Inspector (paid), which every YAPU editor tool depended on, replaced with NovaInspector, built on the open-source TriInspector (MIT) and integrated across 875 files. Not a single file of the engine uses Odin anymore.
  • Text Animator (paid) replaced with my own text animator, written from scratch.
  • DOTween replaced with NovaMotion, OpenMon's own tweening library: proprietary, usable only with OpenMon and not redistributable on its own.

Architecture and code quality

  • The engine split into independent modules with their own assemblies (Core, Foundation, Online, Importer and Setup): the core never depends on the online layer or the importer, and online is opt-in.
  • Clean code with design patterns, architecture changes and code improvements throughout.
  • An engine with no copyrighted content: the game content lives in a separate download, the MIT Licensed Demo.
  • More than 6,000 automated tests in 751 test files.
  • Compiled editions: Indie and Pro with a readable public API and XML documentation, and Starter fully obfuscated.

Anyone who wants to use the original YAPU is free to do so: