Floptle

Floptle is a free, open-source game engine. Host a game with one line of Lua and your friends join with a six-character code, through our relay, from anywhere. Nobody opens a port and you rent no server. Around that sits a whole engine in one native binary for Windows, macOS and Linux: worlds you can carve, an editor, Lua, shaders, physics and audio, and a command line an AI assistant can drive.

New to game development? The tutorials check your work. The editor has a Learn tab with follow-along projects, a 3D platformer, a top-down RPG, Flappy, and each step ticks itself off as your project comes to match it. You are never left wondering whether you did a step right, and the docs one tab over always match the version you are running. It is the way I would want to learn an engine from zero.

Your CI and your AI assistant can drive it using the Floptle CLI (command line interface) Ask whether a project loads, play it headless and get every error with its file and line, render a frame to a PNG, read a scene tree, or change a project through the editor's own scripting API, all without opening the editor. Every command reports whether it needs a display and whether it writes to your project, and floptle help --json describes the whole surface, so an assistant reads the interface once instead of guessing at it.

Carve terrain, down to whole planets. Most engines hand you a heightmap. Floptle stores terrain as a real 3D signed-distance field, so caves, overhangs, tunnels, and floating islands all work, and you can edit any of it while the game is running.

Online multiplayer is one component and one line of Lua. Add the 🌐 Networked component to a node, call net.host{ maxPlayers = 4 }, and you have a real client talking to a real server. No plugin, no service to sign up for, no separate networking library to learn. You pick a replication mode per node and a project that does not use a mode never pays for it.