Now with AI-powered app builder & hosting

BuildReleaseHostDeploy multiplayermultiplatformmultiplayermultiplatform
appsgameswebsapps in minutesusing AIin minutesusing AI

Real-time SDK, hosting, code editor, AI builder, app store, and payments — everything to go from idea to shipped, in one platform. Prototypes that grow into real software.

DevelopersIntegrate Neblla into your current code

// client.js — your front-end. Pair it with lobby.js,
// gathering.js, room.js for server logic. They talk via events.
window.onNeblla = neblla => {
  neblla.joinRoom('game-lobby');

  neblla.on('message', e => {
    console.log(e.user.publicInfo.name, e.data);
  });

  neblla.sendMessage({ move: 'ready' });
};

EveryoneCreate anything with AI

Make me a multiplayer trivia game with 4 categories and a scoreboard

Claude

Done! Your trivia game is live with real-time scoring and room support. Players can join from any device.

🔗 play.neblla.com/trivia-night

Platform

One platform.
Everything you need.

No infrastructure to manage. No boilerplate. Just your idea and a script tag — or just your idea and AI.

⚡

Realtime

Real-Time SDK

Rooms, messaging, an authoritative server, presenter role, and public info — all from a single neblla object. Multiplayer in 6 lines of code.

P2P & File Transfer

Messages and binary files travel directly between peers via WebRTC — no server hop, no quota consumed, no upload limits. Automatic socket fallback for messages.

Rooms & Presenter

Named or auto-generated rooms with presenter election, member tracking, and a 3-minute reconnection grace so users keep their seat across drops and tab reloads.

🌐

Host

Instant Hosting

Every app gets a live URL at neblla.com/id. Hot-served while active, auto-migrated to the edge when idle. Zero config.

Cross-Device Storage

.save() persists per device — and follows users across devices once they log in. State survives reloads, reconnections, and switches.

Custom Domains

Set your own domain for production apps. Sandbox mode available for localhost development. Full control over access.

🤖

AI for Builders

AI App Builder

Describe what you want and get a working app. Iterative "Edit with AI" to refine your creation. No coding experience needed.

Claude MCP Connector

Manage apps, files, and deployments directly from Claude. Full MCP integration — build and ship without leaving the conversation.

Bring Your Own Key

Plug your Anthropic API key in for unlimited AI edits using your own account. Free edits included for everyone to get started.

💳

Payments

Stripe Checkout

Sell digital products in a single call: neblla.buy(productId). Stripe handles checkout and payouts — you just set the price.

Consumables & Entitlements

Track purchases, spend with consume(), and validate other players' purchases. Built for in-app currencies, unlocks, and event tickets.

Anti-Cheat Verification

Continuous server-side checks plus P2P cross-verification between peers. Mismatches are reported automatically and corrected client-side.

🛡️

Trust & Anti-Cheat

Free: Prototype with friends

This is where you start, on purpose. Server-side code runs on one of the connected devices — zero infrastructure, zero deploy, zero cost. Ship a multiplayer app for family and friends in an afternoon, validate the idea, iterate. Built-in safeguards: private user data stays in the user's session, payments are server-mediated, cheaters get banned from the backoffice.

Pro: Scale without rewriting

When the concept clicks and you need real infrastructure, flip a config flag. The same code runs on Neblla's Cloudflare Workers. Same files, same events, same API — no migration, no platform swap. Easy entry, no ceiling.

Anti-cheat features (both tiers)

neblla.confirm(event, value) lets every client report what they saw locally; the server peer compares for unanimity. Mismatch → neblla.flag() auto-fires, bumping flagCount on every user in the room (one flag per room). Devs spot cheaters across rooms in the backoffice.

👑

Presenter vs Server

Presenter = UI host

A social role for asymmetric games — the bingo caller, the Jackbox screen. user.isPresenter tells your client.js who shows the host UI; address them with neblla.tellPresenter(data) (they get a 'messageToPresenter' event). The first device in the room is presenter; if they leave, the SDK promotes another. The presenter does not run the server/ files.

Server = runs server/*.js

The authority — runs server/lobby.js / server/gathering.js / server/room.js. In peer mode it's a device the SDK picks per room (best CPU + lowest median P2P latency); in infra mode it's a Neblla Node process. Address it via neblla.tellServer(data) (it gets 'messageToServer'); broadcasts come back as 'messageFromServer' / 'state'. No neblla.server, no user.isServer — its identity is closure-private so your code survives the peer→infra move.

Two roles, one model

In peer mode they may coincidentally be the same device, but they're separate roles: presenter is a client, server runs the server/ files. neblla.setState(state) from server/room.js replicates the authoritative state to everyone (and to the pre-agreed successor) so a hand-off is instant. Same code keeps working when you move the server to Neblla's infra entirely.

☁️

Neblla

App Store

Publish to the Neblla marketplace. Discover, fork, and remix apps built by the community. Coming to store.neblla.com.

User Login

Drop-in Google sign-in for your players via neblla.login(). Profiles and saves carry across devices — no auth code to write.

Free to Start

50K daily data units, hosting, editor, AI builder, P2P — all included. No credit card required. Upgrade only when you're ready.

Get Started

From zero to live in 4 steps

Whether you code by hand or let AI do the work.

Sign up

Create an app

Click "+", name it, then pick: generate with AI, start from a blank canvas, or fork a template.

Build

Use the Neblla editor, iterate with AI, or manage everything from Claude via MCP.

Ship

Hit publish. Your app is live with a URL, hosted and scaled automatically.

Pricing

Free to start. Scale when ready.

Pay only for real-time data. Hosting and tools included.

Free

Honestly, start here. We're not trying to sell you anything — most apps stay on Free, and the ones that grow scale to Pro without rewriting a line.

50K data units/day
Hosting included
Code editor & AI builder
WebRTC P2P (unlimited)
Claude MCP access

Pro

$10/mo

When the concept clicks. 20× the quota, server-side code on Cloudflare Workers, same simplicity.

1M data units/day
Everything in Free
Priority support
Custom domains (soon)

On-Demand

$10

10M extra data units for spikes, events, or safety net. Lasts a year.

10M data units (one-time)
Used after daily quota
Valid for 12 months
Stack with Free or Pro

A data unit = one character sent or received between your device and Neblla.
P2P messages are always free. Prices are per app.

Ready to build?

Join developers shipping multiplayer experiences with less code and more fun.

Documentation

API Reference

A Neblla app's canonical layout is six files: index.html, main.css, client.js on the front-end, plus three files in a server/ folder split by lifecycle phase — server/lobby.js (matchmaking), server/gathering.js (waiting window before a game starts), and server/room.js (authoritative game logic). Only index.html is strictly required; the rest exist as your app needs them. Client and server communicate through events only — never direct calls (tellServer/tellPresenter/sendMessage/setState + on('messageToServer'|'messageFromServer'|'messageToPresenter'|'message'|'state')). In client.js, set window.onNeblla to a callback and it fires once the SDK is ready. The server/ files are loaded by the SDK and run in an isolated scope (no DOM, no neblla.me) on the room's server peer — never the presenter. Pick the server mode in the Config tab: plain JS on a peer (default, inspectable), AssemblyScript→WASM on a peer (opaque to DevTools), or JS on Neblla's infra (coming soon). Click any item for full details.

Methods

on(event, callback)

Registers a listener. Use '*' for all events.

off(event, callback)

Removes a listener. Empty string clears all.

sendMessage(data)

Broadcasts to everyone in the room. From a client → 'message' (also to you, fromMe); from the server → 'messageFromServer'.

tellPresenter(data)

Private message to the room's presenter (UI host). They get 'messageToPresenter'.

tellServer(data)

Private message to the server (server/*.js). It gets 'messageToServer'.

setState(state)

(server) Publish the authoritative state — everyone gets 'state' and neblla.state.

sendFile(file, options?)

P2P-only binary file transfer. Send to one peer or every peer in the room.

setPublicInfo(info)

Updates your profile and broadcasts the change. Persists across rooms.

joinRoom(room)

Joins a named room. Fires 'joinRoom' on success.

leaveRoom()

Leaves the current room.

createRoom()

(legacy) Books + joins a fresh room in one step. New code uses bookRoom → joinRoom → startRoom.

bookRoom({ config? })

Reserves a unique room name (with an optional config) without joining. Returns a Promise.

startRoom(name?)

Presenter (or server/gathering.js): flip a gathering room into 'running' and boot server/room.js.

save(json)

Persists data locally — and across devices once logged in.

login(opts?)

logout()

Signs the user out and clears the persisted login token.

getFriends()

Force-refresh neblla.friends from the server.

getFriendRequests()

Force-refresh neblla.friendRequests.

requestFriend(target)

Send a friend request to a player currently in this app.

acceptFriend(requestId)

Accept a pending friend request.

rejectFriend(requestId)

Reject a pending friend request.

removeFriend(friendId)

Drop an existing friendship. Works whether the friend is online or not.

inviteToRoom(target)

Invite a friend currently in this app to your current room.

buy(productId, amount?)

Opens a Stripe Checkout popup for the given product.

consume(productId, amount?)

Spends a consumable purchase. Returns the new state.

validatePurchase(userId, productId)

Verifies a peer's purchase against the server.

getProducts()

Returns the public list of products configured for this app.

Properties

neblla.users

Everyone in the current room.

neblla.room

Current room object.

neblla.me

Your own user object (isPresenter, grantedScopes, …).

neblla.presenter

The current presenter (UI host) user, or null.

neblla.state

Latest authoritative state pushed by the server via setState().

neblla.gathering

(in the lobby) Rooms currently in their gathering window.

neblla.purchases

Your purchases keyed by productId.

neblla.friends

Your Neblla friends visible in this app, with online status.

neblla.friendRequests

Pending friend requests you've received.

Events

'message'

A peer broadcast (sendMessage from a client). { data, user, fromMe, time, p2p }.

'messageFromServer'

The server broadcast something (its sendMessage). The authoritative voice. { data, time }.

'messageToServer'

(server) A client called tellServer. Goes to lobby/gathering/room.js by phase. { data, user, time }.

'messageToPresenter'

A client called tellPresenter. Only the presenter device gets it. { data, user, time }.

'state'

The server published a new state via setState. Payload IS the state; neblla.state updated.

'joinRoom'

You successfully joined a room.

'leaveRoom'

You left a room.

'memberJoinedRoom'

A user joined (also for existing users on your join).

'memberLeftRoom'

A user left.

'publicInfo'

A user's public info changed.

'newPresenter'

The presenter (UI host) role changed.

'roomStarted'

A gathering room flipped to 'running'; server/room.js boots. { room, isMe }.

'newServerPeer'

The room's server peer was (re)assigned (first pick / hand-off / mid-game). { room, isMe }.

'gathering'

(in the lobby) The list of rooms in formation changed. { rooms }.

'reconnected'

Socket reconnected and the room has been re-synced.

'sessionExpired'

Server refused to re-issue a session — reload required.

'login'

Sign-in completed (also auto-login on reconnect). Includes grantedScopes.

'logout'

Sign-out completed.

'friendsUpdated'

Your friends list or any friend's online status changed.

'friendRequest'

Someone in this app sent you a friend request.

'friendAccepted'

A request you sent was accepted.

'friendRemoved'

A request was rejected, or a friendship was removed.

'roomInvite'

A friend invited you to their current room.

'purchase'

A room user bought, or anti-cheat corrected your state.

'fileStart'

A peer is about to send you a file.

'fileProgress'

Bytes received or sent during a file transfer.

'file'

A file transfer completed — file is a Blob.

Examples

See it in action

Download any example and start building on top of it.

💬

Chat

Real-time chat with user names and history.

📡

Events

Live events board with real-time updates.

🐺

Werewolf

Social deduction game with roles and voting.

♟️

Chess

Two-player chess with validation and sync.

🎨

Drawing Board

Collaborative whiteboard — everyone draws together.

Legal

Privacy Policy

Information We Collect

Developer info: email address and name to identify you as a user.

Subscription info: your Stripe customer ID and subscription ID.

What We Don't Collect

We do not store passwords, bank details, or payment info. Stripe handles that.

Third-Party Services

We use Stripe for payments and Google for authentication. These services may store cookies for their own purposes.

Data Sharing

We do not sell, share, or disclose your information. Contact [email protected].

My Apps

Pick one to edit, or create a new one.

⏳

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✨

Describe changes, ask questions, or paste errors. Selected files on the left are the context.

Public URL

play.neblla.com/

3–50 characters. Lowercase letters, digits and hyphens. Optional but unique.

Private

This app isn't listed in the public gallery. Toggle on and save to publish.

Cover image

No image

Choose image

Best on

Section Tags

Content per language (click the lang code to set as default fallback)

🛍

Select a product on the left
or create a new one.

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General

Features

Danger

Features

Turn off the SDK features your app does not use. Each disabled feature reduces SDK quota usage and hides its tab from this dashboard.

Domains

Habilitar localhost

Necesario durante el desarrollo local.

Dominios automáticos

Tu app responde en todas estas URLs sin que configures nada (por id y por slug, en los dominios de Neblla + Cloudflare).

Dominios propios

Restringe/añade dónde puede usarse el SDK. Un dominio por línea.

Capacity

Free: —

Extra: —

Breakdown will appear here once your app has traffic.

AI

Enable AI

Allow users to call AI via neblla.ai() (server-side and SDK).

Provider keys

Pick the active provider — only one runs at a time. Used when User token mode = Off.

Claude Not connected

API key

Anthropic key. Managed in your account.

Model

Max output tokens

Per response. Default 1024.

OpenAI Coming soon

API key

OpenAI key. Available once backend support lands.

Model

Max output tokens

Per response. Default 1024.

Rooms

Multiplayer rooms exposed via the SDK (neblla.bookRoom(), neblla.joinRoom(), neblla.room.setData()).

Room types

Pick which room types your app exposes — they're combinable. Ephemeral rooms exist only while users are connected (no DB, no chat history). Public rooms persist; anyone in your app joins. Private rooms persist with a whitelist managed by intra-room owners.

Ephemeral

Session-only rooms, destroyed when empty. Current default behaviour. No DB writes for room state or chat.

Public

Rooms persist across restarts. Anyone in your app can join. Chat history survives. Good for forums, lounges.

Private

Persisted rooms with a whitelist. Owners invite, kick, promote. Good for guilds, party chats.

Default type

Used when persistRoom() is called without a type.

Max data size (bytes)

Cap on JSON.stringify(room.data). LOBBY uses 10× this value.

Matchmaking

Decides WHEN a gathering room flips to running. Custom: you own server/gathering.js. No-code: pick a rule below and Neblla regenerates server/gathering.js for you on save (edits to that file are overwritten while no-code is on).

Mode

Conexión entre dispositivos

Por defecto los dispositivos se conectan directamente entre sí (P2P), sin pasar por Neblla: es gratis y no consume cuota. Si en una red no es posible la conexión directa, Neblla puede mediar el tráfico — eso sí consume cuota (no pasa por la RAM de tu app, es solo reenvío de red).

P2P directo entre dispositivos

Conexión directa (WebRTC). Gratis. Necesaria para la transferencia de ficheros P2P. Por defecto activado.

Si no hay P2P, que Neblla medie consume cuota

Mantiene la conexión en redes restrictivas (NAT simétrico, firewall) reenviando el tráfico por un relay de Neblla. Asumible para datos pequeños (p. ej. ajedrez); para file-transfer o drawing board puede ser caro — tú decides por app.

Server mode

Where the server/ files (server/lobby.js, server/gathering.js, server/room.js) run, and how exposed they are to inspection. Whatever you pick, the same code keeps working — that's the point of the events-only contract.

Peer · JavaScript Free · Default

Plain JavaScript. Runs on whichever connected device the SDK picks as the room's server peer. Inspectable from DevTools on that device — fine for casual social/party games.

Peer · AssemblyScript → WASM Free · Types required

You write server/lobby.ts, server/gathering.ts, server/room.ts in AssemblyScript. Compiled to WASM in your browser at save. Still runs on a peer, but state and logic are opaque to DevTools.

Neblla infra · JavaScript Beta

The server/ files run on a Neblla worker — one per room, no device involved. Uninspectable, no hand-offs. For competitive games, real money, tournaments, ranked. (Beta — the events-only contract is the same; your code doesn't change.)

Honesty caveat: AssemblyScript→WASM defeats casual cheaters (DevTools, console). It does not defeat motivated reverse-engineering with tools like Ghidra or Binary Ninja. For real-money or ranked games, the right answer is the Neblla infra mode.

Database — bring your own

By default Neblla stores each user's data, room data and communications on its own libSQL/Turso cluster (counts toward your storage quota). You can point Neblla at your own database instead — at no quota cost, fully under your control. Everything else (identity, friends, purchases, anti-cheat flags) stays on Neblla. Connection strings and tokens are encrypted at rest; the browser never sees them again after submit.

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Copiar configuración de otra app

Clona ajustes de comportamiento (funciones, salas, emparejamiento, IA, P2P, permisos, tema) de otra de tus apps. No copia identidad, dominios ni hosting.

Engine

What "Start migration" does: the migration runs in three phases. (1) Live bulk copy of all user data to your database. (2) Live delta copy of anything that changed during phase 1. (3) A brief lock (seconds) to copy the final delta and switch the pointer. Your app emits an 'app_maintenance' event during phase 3 so you can show your users a "we'll be right back" message. Total time depends on data volume; typical is minutes for an indie app.

Permissions

When users open your app, Neblla shows a consent screen for the data your app wants to read about them. Each scope below has a justification you write — it appears verbatim, in quotes, with your app's name, in the user's gallery permissions screen and in the consent popup. A clear, honest reason gets more yes's; vague or absent text makes users default to no. Max 200 characters per scope.

📧 See user email

Optional. Email is not required for any app to function — Neblla identifies users internally. Only ask for it if your use case truly needs it: cross-referencing accounts between your apps, importing data from systems outside Neblla, or sending email outside the platform. Users see this as a serious request and many will refuse without a strong reason.

👥 See user's friends list

Useful for social features: invite friends to a room, show who's online in your app, build leaderboards limited to friends. Users grant this more readily than email — but the explanation still helps.

📡 Be visible to friends inside this app

When granted, this user appears as online inside your app to their friends — enabling room invites, "play with friends" lobbies, and presence indicators. Without this, friends can read each other's friend list but can't tell who's currently in your app.

Inbox

Bidirectional messaging between users and you via neblla.inbox().

Max inbox per user

Leave empty for account default.

Max outbound per user

Leave empty for account default.

Danger zone

Delete this app

Permanently remove the app, all its files and its gallery listing. This cannot be undone.

No messages.

Select a message to read.

Settings

Account

Public Info

Your public name and picture. The name will appear as the owner of all your apps.

✎

Preferred language

Messages from other users will be automatically translated into this language.

Email Addresses

Manage email addresses linked to your account. The primary email is used for notifications.

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Password

Choose a strong password — at least 8 characters.

API Token

Your token expires after 15 days of inactivity. Rotating invalidates the current one immediately.

🤖

Anthropic Claude

Add your API key for unlimited AI-powered file edits using your own account.

Not connected

Your key is stored encrypted and only used for AI edits you request. It never leaves Neblla's backend and is not shared with the client.

Get your API key at console.anthropic.com.

💳

Stripe Connect

Accept payments directly in your apps. You keep the money — Neblla takes a small platform fee.

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🌐

GoDaddy

Point a custom domain you own to any Neblla app.

Coming soon

Connect your GoDaddy account and auto-configure DNS for any domain you own. Your apps get a real address — no copy-pasting CNAME records.

Delete Account

This will permanently delete your account, all your apps, and all associated data. This cannot be undone.

BuildReleaseHostDeploy multiplayermultiplatformmultiplayermultiplatform appsgameswebsapps in minutesusing AIin minutesusing AI

One platform.Everything you need.

Realtime

Real-Time SDK

P2P & File Transfer

Rooms & Presenter

Host

Instant Hosting

Cross-Device Storage

Custom Domains

AI for Builders

AI App Builder

Claude MCP Connector

Bring Your Own Key

Payments

Stripe Checkout

Consumables & Entitlements

Anti-Cheat Verification

Trust & Anti-Cheat

Free: Prototype with friends

Pro: Scale without rewriting

Anti-cheat features (both tiers)

Presenter vs Server

Presenter = UI host

Server = runs server/*.js

Two roles, one model

Neblla

App Store

User Login

Free to Start

From zero to live in 4 steps

Sign up

Create an app

Build

Ship

Free to start. Scale when ready.

Ready to build?

API Reference

on(event, callback)

off(event, callback)

sendMessage(data)

tellPresenter(data)

tellServer(data)

setState(state)

sendFile(file, options?)

setPublicInfo(info)

joinRoom(room)

leaveRoom()

createRoom()

bookRoom({ config? })

startRoom(name?)

save(json)

login(opts?)

logout()

getFriends()

getFriendRequests()

requestFriend(target)

acceptFriend(requestId)

rejectFriend(requestId)

removeFriend(friendId)

inviteToRoom(target)

buy(productId, amount?)

consume(productId, amount?)

validatePurchase(userId, productId)

getProducts()

'message'

'messageFromServer'

'messageToServer'

'messageToPresenter'

'state'

'joinRoom'

'leaveRoom'

'memberJoinedRoom'

'memberLeftRoom'

'publicInfo'

'newPresenter'

'roomStarted'

'newServerPeer'

'gathering'

'reconnected'

BuildReleaseHostDeploy multiplayermultiplatformmultiplayermultiplatform
appsgameswebsapps in minutesusing AIin minutesusing AI

One platform.
Everything you need.