ForkBuild

Build in 3D in your browser. Remix anything. Own your work.

Try it now: no account, no download.

Build a little place. Anyone can remix it. Walk inside it with friends.

ForkBuild is a 3D building game in the browser. You snap bricks into a house, a bridge or a whole village, publish it, and share a link. Anyone who opens it can make their own copy, credited to you, and build on it. Then you walk through what you made, together.

1. Try it now opens a little house with no roof and a job in four steps: a roof, a chimney, a path and a garden.
2. Publish is one sheet: your name, Others may remix it and Everyone can find it, already chosen.
3. Walk inside it puts your avatar at its door in a shared World.
4. Its link opens on the build itself, with its family tree and one Edit a Copy button for whoever opens it.

The three things every feature serves (docs/Pillars.md):

• Building feels joyful: fifty-nine bricks, quick and forgiving to place, on a computer or a phone.
• Every build has a family tree: a remix remembers what it came from, so credit travels with the work, and a weekly challenge gives everyone something to build together.
• Your work is yours, and lives in a world: builds stay on your device, signed with a key you hold, with no account; and each one is a place to walk into, alone or with friends. How that works, and the networks a build can go to, is in How your work stays yours.

Version 1.6.1, released 2026-10-29: see the release notes. It is about a first build that gets published: Publish in one sheet with remixing on, Try it now's house with a job in four steps, a first walk in daylight with a clearing round every build, and an Editor that places only on a click, lays rows with Shift+drag, picks a brick from the build and moves what you select by dragging it; and 1.6.1 holds the World in a seasonal challenge week's season all week. Update before 16 November 2026, the winter cabin's week, when older copies see other seasons and copies older than 1.5.0 other themes. 1.1.0 fixed two security problems in 1.0.0, so update any copy older than that. Every milestone is recorded in docs/Roadmap.md.

docs/VISION.md has the longer-term aim.

Features

Home

• A landing page with a slowly turning 3D village and ready-made builds (a castle, a harbor island, a village square, a house, a mill and a bridge) that open in the Editor as your own copy, with no account needed; the Repository, My Worlds and the Editor's New offer them too. Link previews and an installable web app manifest for the site.
• Your stamps: once you have published, Home shows facts about your own builds (published, remixed by others, challenges entered, a build of a hundred bricks or more), worked out on this device. Credit, never points or a ranking.
• A weekly build challenge: a new theme every Monday (a lighthouse, a bridge, a tiny home, …), each with a twist, with Join the challenge, which opens an empty plot tagged for the week with the theme's ideas pinned in the Build Library, and a Challenge page listing the entries found on this device and on Nostr and Arweave. Every fourth week is a remix week: an entry starts as a copy of one of last week's. No server decides the week: every copy of the app works out the same theme and tag from the date.

Editor

• Place, select (single, multi, marquee), move, rotate, tilt onto another side and delete bricks, with undo/redo, grid snapping and a placement preview.

• Shift+drag lays a row of bricks in one stroke; Alt-click (or a long press on a touch screen) picks up a brick from the build, colour and turn included; the number keys 3 to 9 hold the bricks used lately; dragging a selected brick moves it; and See the Whole Build brings a lost view back.

• Interactive transform gizmo, numeric transform input, snapping, and alignment and distribution tools.

• Groups, clipboard, brick colors with a palette of village colors, and a command palette (Ctrl/Cmd+K) that shares one action registry with the sidebar and keyboard shortcuts.

• Fifty-nine bricks, from half cubes, round bricks and logs to gable and cone roofs, framed and round windows, fences, benches, bushes and pine trees, furniture for inside (a table, a bed, a hearth and a shelf), and a lantern that lights up at night. Each looks like what it is made of: masonry courses, plaster, wood grain, roof tiles, glass or leaves, with a soft line along its edges, in whatever colour you paint it.

• A Build Library of bricks and ready-made structures, a personal blueprint library, structure placements, and document export/import.

• Save, autosave with crash recovery, and publishing to an immutable, content-hashed snapshot.

• A guided first build: six steps (place a brick, stack one, add something of your own, save, share a link, walk inside it) ticked off as you do them, ending in a small celebration. Home's Try it now house comes with a job in four short steps (a roof, a chimney, a path to the door and a garden), shown one at a time while the guide waits. Logging in is asked for only when you first publish.

• Walk inside it: once a build is published, one click opens World View with your avatar in front of its door, facing it; the door swings open as you walk up.

• Build with me makes a link that opens your build in a friend's Editor, so you build it together, live: each brick either of you places appears on both screens, and each sees where the other is pointing and what they have selected, until you press Stop. Undo takes back your own steps on every screen, never a friend's. Everyone who built is credited on the build, in every copy: published, its link and family tree say who built it with you, each name opening that person's page, and My Worlds lists the builds you helped make.

• Share a build the moment it's published: the link carries the signed build itself, so it opens on any device with no wallet or account, shows the build's title and a picture of it when pasted into a chat or a post, and downloads a PNG of it to post alongside.

World View

• A shared world where published creations are placed and streamed in around the camera, on deterministic terrain with vegetation, water and wildlife. Each published build gets a spot of its own, with room round it; the weekly challenge's plaza shows that week's entries round its square.
• Walk in the main menu opens that plaza, with the ready-made builds standing round the square while a week has few entries, so there is somewhere to walk before you've built anything.
• Day and night: every 40 minutes the sky turns through dusk to a moonlit night and back, the same for everyone; the sun and then the moon rise in the east and set in the west, lighting builds from where they stand and casting shadows near you (Shadows, on by default except on phones); at night the stars and the Milky Way come out and wheel across the sky; windows and lanterns light up after dark and crickets take over from the birds. Always day keeps it day. A visit's first look at World View is in fair morning light, easing into the shared sky over two minutes, and every build stands in a clearing, so you see its door as you arrive.
• An avatar you can walk, run and jump with, which collides with buildings and can climb stairs and slopes, with no name needed: until you choose one you walk as a guest only you can see; vehicles, an inventory, and catching and releasing animals.
• Residents: people a World's author adds, who stroll around their homes, walking round buildings, turn to greet you, and tell you what's around — with a Focus button to look at what they mention.
• Build here starts a new build in the Editor for the spot you're standing on; publishing it stands it there.
• Walk here with me makes a link that brings friends into the World you're in: they log in, click Join, and you see each other walking around, with no invitation to paste back and no lobby.
• Text and spatial search, a map, named regions and landmarks, and World Encounters with publications that connected peers are sharing.
• World View observes and navigates; editing happens in the Editor. Edit a Copy forks what you're looking at into the Editor. See docs/CapabilityMatrix.md.

Phones and tablets

• Touch controls in both views: a joystick and buttons for walking (with a hands-free Cruise), riding, storing vehicles, catching and decorating in World View, and tap-to-place with an Undo, Redo, Rotate, Delete and Multi-select bar in the Editor. On narrow screens the menu and side panels fold away so the 3D view fills the screen. See Touch screens.

Remixing and sharing

• Every published build is a fixed snapshot. A remix is a new build that records where it came from, subject to the original's license.
• Explore and each builder's page, with search, sorting, pagination and pictures of each build made on your device.

Friends

• An opt-in public lobby, one for everyone and one per World, for meeting people whose identity you don't know yet.
• Remembered peers, mutual-consent friendships, private one-sided follows (a Following page and notifications for new work by people you follow) and blocking.
• Chat with offline queuing, persistent history and read receipts, and voice calls.
• Avatar profiles, presence, gestures and per-audience visibility, all shared over authenticated peers.
• Collaborative World editing with signed membership grants.

Your data

• Everything lives in this browser. Your Data backs all of it up to one passphrase-encrypted file and restores it here or on another device, adding what's missing or replacing everything. Copy to another device shows a one-off QR code instead: scanning it with a phone, or opening its link in another browser, copies everything there directly, encrypted with a key only the code holds. Documents, structures and identities also export on their own pages, all at once or one at a time, and each of your publications in the Repository says where this device recorded distributing it. A reminder appears when the last backup is old, a backup can go to your device's share sheet, and Chrome and Edge can back up daily to a folder your cloud storage syncs. See Your Data.

How your work stays yours

Under the game, ForkBuild is open source and decentralized: builds are published through interchangeable storage and announcement networks, and nothing depends on a ForkBuild server being up. There are no accounts: identities are key pairs held on your device, and people connect to each other directly over authenticated peer connections. The only server the default setup uses is a rendezvous server that helps peers find each other, plus an anonymous, cookie-free visitor count once a day that you can turn off; see docs/Privacy.md for everything the app contacts.

• A build is a signed document kept on your device, in an open format (docs/Protocol.md) any copy of ForkBuild can open, check and remix with its maker's credit.
• Decentralized publication: content on Arweave or IPFS and announcements over Nostr or Arweave and anchoring evidence on Arweave, managed from the Signed Records page, plus (experimental, see below) Steem, Blurt and anchoring on Bitcoin, Base, Steem or Blurt. All of it is verified by content hash and signature, never taken on trust.
• Ed25519 identities (did:key) held on the device, signed with the audited noble-curves library. Private keys are encrypted with a passphrase (PBKDF2-SHA256 and AES-256-GCM through the browser's WebCrypto), offered whenever an identity is made; a first publish or walk needs only a name, and its identity shows as ⚠ Unprotected, with a reminder, until a passphrase is added. Export/import, succession, revocation and multi-device grants.
• Direct WebRTC peer connections found through rendezvous or a manual invitation, and authenticated with a challenge–response handshake.

Experimental

These areas work, but may change or be removed in a later version, and what they produce may not carry over. The app marks them with an Experimental banner, or, on the Signed Records page, an Experimental badge. The Signed Records page's tools panel and the Bitcoin Endpoint page are listed only after Show experimental tools is turned on in Network Settings (More → Advanced):

• external evidence and anchoring on Bitcoin, Base, Steem and Blurt (anchoring on Arweave is a regular feature), the Bitcoin and Base wallets, and their Network Settings;
• Steem as a place to store and announce builds (added in 1.1), and remote IPFS pinning;
• the Signed Records page's Wallet & Archive Tools panel.

The rest of the Signed Records page (the list and statuses, removing records that can't be used, announcing on Nostr or Arweave, storing on IPFS or Arweave, and a card's four tabs) is a regular feature.

Quick Start

ForkBuild has no build step, but it loads as native ES modules, so serve the repository folder over HTTP rather than opening index.html from disk. For example:

python3 -m http.server 8000

Then open http://localhost:8000/. Every script, including Vue and Three.js, is served from the repository's own vendor/ folder, so the app loads without internet access (its network features still need it). To host it, see docs/Deployment.md.

To run the tests you need Node.js 22 or later:

npm install
npm test

npm test runs every test file under Node (npm run test:node), the rendezvous worker's tests (npm run test:worker) and the few tests that need a real browser in headless Chromium (npm run test:browser; install Chromium once with npx playwright-core install chromium, or point CHROMIUM_PATH at an existing one). Pass a filter to run matching files only, for example npm run test:node -- Avatar. The same checks run on every pull request.

Peer discovery through rendezvous needs a rendezvous server; a reference Cloudflare Worker is in server/rendezvous-worker/.

Architecture

ForkBuild is layered as core / application / renderer / ui, with infrastructure adapters around them:

• core/: the pure domain model and value types. No Three.js, no Vue, no browser APIs.
• application/: use cases, sessions (Editor, World View, published world), commands and services.
• renderer/: Three.js rendering, driven incrementally by domain events.
• ui/: Vue 3 views and components; ui/main.js is the composition root.
• Adapters: storage, serializer, publisher, discovery, identity, peer, presence, collaboration, replication, placement, spatial, content, anchoring, and the Nostr, Arweave, Base and Steem integrations.

See docs/Architecture.md for the full description.

Documentation

• docs/Pillars.md: what ForkBuild is for, the three pillars every feature serves, and the words players see.
• docs/user/: user guides, including the Controls Reference.
• docs/Architecture.md: how the system is built today.
• docs/Principles.md: the design rules the code keeps.
• docs/Protocol.md: current serialized and wire formats.
• docs/Deployment.md: hosting requirements, the vendored libraries and the Content Security Policy.
• docs/CapabilityMatrix.md: what each surface (Editor, World View, published world) may do.
• docs/AnnouncementIndex.md: how announcements are recorded, synced in the background and shared between peers.
• docs/DeveloperFAQ.md: answers to questions contributors often have, with pointers into the code.
• docs/NowNextLater.md: what comes next, in order, at most three items each.
• docs/Roadmap.md: every milestone and why it was made. This is the project's changelog.

Security, privacy and contributing

• SECURITY.md: how to report a vulnerability, and what is in scope.
• docs/Privacy.md: what ForkBuild stores, and every server it can contact.
• CONTRIBUTING.md: how to set up, test and submit changes.
• docs/ReleaseNotes-1.6.md, docs/ReleaseNotes-1.5.md, docs/ReleaseNotes-1.4.md, docs/ReleaseNotes-1.3.md, docs/ReleaseNotes-1.2.md, docs/ReleaseNotes-1.1.md and docs/ReleaseNotes-1.0.md: what each release includes and changed, how to upgrade, and known limitations.

License

Mozilla Public License Version 2.0. See LICENSE.