You spent a weekend vibe-coding a game. Claude Code or Cursor wrote most of it, Rosebud or Lovable maybe generated the first pass, and now you have something that actually plays: a runner, a puzzle game, a small roguelike. It works in the browser, it's fun for two minutes, and then you hit the wall every small game hits at the same point: it has no memory. Nobody's score is saved anywhere, there's no leaderboard to compete on, and if a player closes the tab their progress is gone.

The instinct is to add a real backend. Then you remember what that involves: a Firebase project or a Supabase project, an auth flow, a database schema for scores and saves, security rules so one player can't overwrite another player's data, and a client SDK wired into a codebase an AI agent wrote in an afternoon. For a small game you're not sure anyone will play, that's a lot of infrastructure to stand up before you find out if the leaderboard even matters.

This post covers what that setup actually costs, and a shorter path if your game is published through Sprixen's Game Creator: a hosted backend called Sprixen Live that gives a published game guest/login identity, cloud save, leaderboards, achievements, inventory, analytics and multiplayer rooms through one SDK object, with no database or auth provider to configure yourself.

What "add a leaderboard" actually requires with a generic backend

A leaderboard sounds like one table: player, score, done. In practice, doing it safely means:

Identity. You need to know who submitted a score, even if they never made an account, or anyone can spam the board with fake entries under any name.
A database with rules. Firestore or Supabase's Postgres both work, but you have to write the schema and, more importantly, the security rules that stop a player from writing an arbitrary score directly from the browser console. This is the part that's easy to get wrong: without server-side validation, "submit score" is just "write any number you want to a public table."
A submit endpoint or rule, not just a raw write. The safer pattern is a small serverless function that validates the score against something (a session, a replay, a rate limit) before it lands in the table. That's another service to deploy and keep alive.
A read query with ordering and pagination for the actual leaderboard view.

None of this is exotic. Any competent AI coding agent can write a Firebase or Supabase leaderboard in an hour if you ask precisely. The real cost is what happens after: a second project to sign into, a second dashboard to check when something breaks, and a security surface (auth rules, API keys, CORS) that has nothing to do with your game and everything to do with keeping the backend from being abused.

The Sprixen Live path: one SDK object, no database to design

If your game is built and published through Sprixen's AI Game Builder, publishing it gives it a public URL under sprixen.com/play/<slug>, and every published game template already includes a client file, src/sprixen-live.js, that exposes a window.SprixenLive object. There's no separate account to create for the backend and no schema to design. You turn on the features you want in the project's Live tab (or via the API), and the SDK talks to Sprixen's own service.

Initialize it once, near the top of your game's boot code:

await SprixenLive.init({
  gameSlug: 'your-published-game-slug',
  loginMode: 'guest_allowed',
  features: ['cloudSave', 'leaderboards', 'achievements', 'inventory', 'analytics']
});

loginMode: 'guest_allowed' is the important default for a small game: a player gets an identity the moment they load the page, no signup form in the way. If you want saves and scores tied to a real account instead (so progress survives a cleared browser), the other modes are login_for_save, which only prompts when the player tries to save, login_required, and creator_custom for a login flow you build yourself.

Cloud save

Save and load take a slot name so a game can support multiple save files, plus an optional checkpoint label:

await SprixenLive.save('default', { level: 3, hp: 7, inventory: ['sword'] }, 'level-3-start');

var save = await SprixenLive.load('default');
if (save) {
  restoreGameState(save.data);
}

There's no schema to define ahead of time. The payload is whatever JSON your game state serializes to, per player, per slot.

Leaderboards

await SprixenLive.submitScore('speedrun', 142, { mode: 'endless', seed: 8831 });

The first argument is the leaderboard key (create it once from your project's Live tab, or via the API if you're scripting setup), the second is the score, and the third is optional metadata that shows up next to the entry in your creator dashboard. Reading the board back is a plain public GET (/v1/live/games/<slug>/leaderboards/<key>) if you want to render it yourself, or you can use whatever UI the game template already provides.

Achievements

await SprixenLive.unlockAchievement('first_win');

One call, one key you defined ahead of time. Unlocks are idempotent from the player's side, calling it twice doesn't double-award anything.

Analytics

SprixenLive.track('match_started', { mode: 'casual' });

This is fire-and-forget event tracking, useful for answering "does anyone actually reach level 3" without wiring up a separate analytics tool for a game this small.

Public lobbies and invite links

If the game supports more than one player in the same session, Sprixen Live also handles lobby creation and discovery:

var lobby = await SprixenLive.createLobby({ name: 'Casual Room', maxPlayers: 2, isPublic: true });
var lobbies = await SprixenLive.listLobbies();

And for real-time rooms, connectRoom gives you a server-authoritative connection rather than a peer-to-peer one, which matters the moment you care about someone cheating on position or score:

var room = await SprixenLive.connectRoom('generic_room', {
  maxPlayers: 4,
  inviteCode: new URLSearchParams(location.search).get('invite') || undefined
});

room.send('state_update', { payload: { x, y, hp }, seq: tick });
room.onStateChange(function(state) {
  // render remote players from state.players
});

For a 2D platform brawler specifically, there's also a purpose-built physics-authoritative room (rift_clash) rather than the generic identity/relay room shown above; that one runs the actual game physics server-side, not just player identity and chat.

What you get and what you're giving up

The honest tradeoff: this only removes setup cost for games published through Sprixen's own Game Creator. That's where the SDK file is injected automatically and where the runtime config, login mode, feature toggles and per-game limits (max players per room, max concurrent players) are already wired to a project you own in Sprixen. It is not, today, a drop-in npm package you add to an arbitrary Phaser or Godot project hosted somewhere else.

Sprixen Live does expose a public SDK file at /v1/live/sdk.js and the underlying API supports registering an app with sourceType: "external", meaning a game built and hosted outside the Game Creator can technically call the same save, score and lobby endpoints with its own client key. But this path is early: there's no published npm package, no dedicated quickstart for external games, and no self-serve screen for it yet in the product. If you're already all-in on the Sprixen Game Creator, the leaderboard-and-save path above works today. If your game lives entirely outside Sprixen and you just want a hosted backend, treat this as a feature to watch rather than a finished integration, and evaluate it against the alternatives below.

How the alternatives compare

None of these are wrong choices. The right one depends on how much of your game already lives inside Sprixen, and how much control you want over the backend's shape.

Option	Setup for a small HTML5 game	Real-time multiplayer	Best fit
Firebase (Firestore + Auth)	Create project, write security rules, wire client SDK by hand	Not built for it; you'd layer Realtime Database or a separate service on top	You want full control and are comfortable owning the security rules
Supabase	Create project, design Postgres schema, write Row Level Security policies, wire client SDK	Realtime channels exist but aren't a game-server room model	You already know SQL and want a backend you can query and inspect directly
PlayFab	Full game-backend platform, more concepts to learn (titles, entities, CloudScript)	Yes, with a real multiplayer server product on top	A larger or commercial project that needs the deep feature set and can absorb the learning curve
Nakama / Heroic Labs	Self-hostable open-source game server; free to run, but you own the ops	Yes, mature and widely used	You want an open-source server you fully control and don't mind running it yourself
Colyseus	Open-source multiplayer framework; you write the room server logic yourself	Yes, this is its whole purpose	You want to write your own authoritative game server in JavaScript/TypeScript
Playroom	Lightweight multiplayer SDK aimed at quick web games, minimal server-side setup	Yes, peer-to-peer style, good for casual local-feel multiplayer	A quick party-style game where you don't need persistent saves or leaderboards, just players in a room
Sprixen Live	Already wired into a published Game Creator project; toggle features, no schema or rules to write	Yes, server-authoritative rooms plus lobbies, invites and matchmaking	A game you built and published through Sprixen's Game Creator

If you're not using the Game Creator at all, and your game was built in Claude Code or Cursor as a standalone Phaser or vanilla JS project, Firebase or Supabase remain the more mature choice today for anything beyond a toy leaderboard. See this walkthrough for how that Phaser + Cursor setup usually looks, and this one for wiring Claude Code to Sprixen for the art side even if you're not using the Live backend.

A worked example, start to finish

Say you built a simple endless runner and want a leaderboard plus a "resume where you left off" save. Assuming the game is already a Sprixen Game Creator project and published:

In your project's Live tab, turn on Sprixen Live and enable cloudSave and leaderboards. Create a leaderboard with key high_score.
In your game's startup code, call SprixenLive.init once with loginMode: 'guest_allowed' so players don't hit a signup wall before their first run.
On game over, call SprixenLive.submitScore('high_score', finalScore).
On boot, call SprixenLive.load('default') to check for a save, and offer a "continue" option if one exists.
Periodically (every level, or every 30 seconds) call SprixenLive.save('default', currentState) so a crash or closed tab doesn't lose progress.

That's the entire integration. No database migration, no auth provider, no security rule to write by hand, because the rule ("a player can only write their own save and score, under their own identity") is already enforced server-side by Sprixen Live.

When to skip this and just use Supabase

If your game isn't published through Sprixen, or you specifically want a backend you can query with raw SQL, extend with your own tables (a marketplace, a friends system with custom logic, cross-game data), or self-host, Supabase or Firebase are still the right call. They're general-purpose, well-documented, and not tied to any one game platform. Sprixen Live trades that generality for zero setup, in exchange for living inside the Sprixen ecosystem.

FAQ

Does Sprixen Live work if my game wasn't built with Sprixen's Game Creator?

The underlying API supports registering an external app (sourceType: "external") and a public SDK file exists at /v1/live/sdk.js, so it's technically reachable. But there's no polished onboarding for that path yet, no published npm package, and no self-serve setup screen. Today, the smooth path is a game built and published through the Sprixen Game Creator.

Do players need to create an account to use cloud save or the leaderboard?

No, if you set loginMode: 'guest_allowed'. A guest identity is created automatically. If you want progress to survive a cleared browser or a new device, use login_for_save or login_required instead so players are prompted to log in at the right moment.

How is this different from just writing scores to Firebase myself?

Functionally, both end up storing a score against a player identity. The difference is what you have to build to get there: with Firebase or Supabase you design the schema, write the security rules, and deploy any validation logic yourself. With Sprixen Live, the identity, storage and validation already exist behind the SDK calls, at the cost of only working for games published through Sprixen.

Can I see who's on the leaderboard and moderate bad actors?

Yes. Every game project has a Live tab with an Overview, Players, Rooms, Data and Analytics view, and creator-only moderation endpoints to ban or mute a specific player if needed.

What does this cost?

Sprixen Live is included in the existing $10/month plan alongside asset generation; there's no separate line-item price for turning on cloud save, leaderboards or achievements on a project you already publish.

Is the multiplayer connection actually secure, or can a player just send a fake score from the browser console?

Score submissions go through Sprixen's server, tied to the player's session, not a raw client-side write to a public database. For real-time rooms, state is server-authoritative rather than trusting whatever position a client reports, which is the same reason you wouldn't want a naive peer-to-peer setup for anything competitive.

How to Add Leaderboards and Cloud Save to a Vibe-Coded Browser Game (No Backend Setup)