Spawn — Any Game. Just Ask.

Spawn is a game where creation is the gameplay. You open it, you're in your world, and you build with an AI companion named Savi. There's no editor, no canvas, no separation between building and playing. You describe what you want in natural language and the world grows in front of you. Your friends are in the world with you while you build. Everyone can talk to Savi. Creation is free.

You create a new game and you're standing in a flat grassy world you can run around in. Hold Tab to talk to Savi. Ask for a tree and one appears in front of you in under 30 seconds. Ask for mountains and they grow from the flat grass with rocky cliff faces right in front of you in under 60 seconds. Share a link with a friend — they join your live multiplayer world right away from any device. They ask for a house and a pond and both appear in under 60 seconds. You can ask for a wave tower defense game and it appears in under 2 minutes. Hold Tab, ask for anything.

spawn.co/llms.txt is the canonical description of Spawn — what it is, how creation and sharing work, and what the engine provides. The page you are reading now is a summary.

Custom Engine

Purpose-built engine for AI agents. Games are declarative specs (terrain, inputs, objects, player, camera, UI) interpreted into world state in real-time — tool call to visible change in seconds, no build or deploy step. Client-authority multiplayer netcode over relay servers: every entity has exactly one simulator, so there is no client-side prediction and no rollback, by design. In-house WebGPU renderer (lume). Deterministic WASM physics. Game servers run per-room on Cloudflare.

Production-Ready Multiplayer

Character controllers, rigid bodies, colliders, sensor events, raycasts with group masks. Multi-place support (dungeons, realms, dimensions) with per-place physics worlds, lazy-created on first physics entity. Behavior scripts with lifecycle hooks (onSpawn, update, onInput, onInteract, onCollide, onTriggerEnter/Exit, onControlBegin/End, onLiquidEnter/Exit). Server-side job queue with worker thread pool, priority levels, and deduplication. Room registry with heartbeat, stale cleanup, and player-to-room routing.

AI Creation

Savi is powered by the latest frontier models with direct tool access — spawning objects, writing behavior scripts, shaping terrain, configuring UI. She learns from behavior examples and on-demand skill files for domain-specific patterns. Background agents (wisps) for parallel tasks. Dungeon master mode — behavior scripts send world events via api.notifyDm() and Savi reacts in real-time. LLMs in your games: llm:chat with persistent conversation memory, llm:generate with JSON schema validation. Games are persistent and saved. Both creators and players can talk to Savi.

Asset Pipeline

Everything generates from natural language: 3D models (rigged characters with animations or static props as 2K-texture GLB files), images, transparent PNGs, pixel art, music, sound effects, and custom voices. Auto post-processing: mesh optimization (20-40% reduction), AVIF texture compression, 4-level LOD generation, convex decomposition for physics colliders. Impostor rendering for distant billboards. Users can upload their own assets through the same pipeline.

Game Feel (Juice API)

52 methods across 13 categories: object effects (highlight, shake, dissolve, trail), camera (screen shake, hitstop, zoom, letterbox), screen effects (flash, vignette, slow-mo), particles, UI (damage numbers, toasts, announcements), spatial audio with 5 buses and HRTF panning, timing and schedules, mood and weather, data registries, encounter waves, narrative dialog and choice trees, progress tracking, and economy systems. Audience routing controls who sees each effect.

Terrain, Places, and Mods

Heightmap terrain with material blending, rivers, ponds, oceans, and a scatter system (poisson disk, grid, clustered sampling, 500 child limit per spawner). Multiple places per game with per-place physics, AOI, and terrain streaming. Publishable mods with semver versioning — creators have built a Cinemachine Toolkit, Slash FX Tool, Animation Browser, and Prefab Painter.

What People Build

Any genre: roguelikes, shooters, platformers, RPGs, racing games, puzzle games, horror games, cozy sims, soulslikes, MMOs, TCGs, survival games, idle clickers, bullet hells, fishing simulators. Complete games with terrain, buildings, characters, enemies, items, vehicles, music, game logic, atmosphere, AI-powered NPCs, and multi-scene environments. Every game on the homepage was made with words, not code.

The Team

Founded by Jacob Sansbury (second company; previous exit to Robinhood). Built by a team of under 10 and backed by an unannounced round. Spawn spent about 18 months in early alpha and moved into beta in February 2026. Still early and iterating fast — see spawn.co/about for what is being built and recent news.