Add ENet multiplayer (movement/combat sync) and matchmaking API

Networked play, end to end: connect, get matched, spawn, fight, respawn.

Godot side:
- Replace the single hardcoded Player with per-peer networked ships
  (MultiplayerSpawner + custom spawn_function), driven by client-side
  prediction with server reconciliation for movement.
- Server-authoritative combat: bullets, health, death/respawn all decided
  by the server and broadcast to every peer over RPC.
- Fix a Camera2D bug where Godot auto-promotes the first camera to ever
  enter the scene tree as the active one regardless of its own `current`
  value — with MultiplayerSpawner catch-up replication that was almost
  never the local player's own ship. `make_current()` on the owner's
  camera fixes it; property assignment doesn't reliably override the
  auto-claim.
- Fix two "late joiner never learns already-established state" gaps
  (health, visibility) by folding both into the existing per-tick
  position broadcast instead of relying on one-shot RPCs that only reach
  peers already connected when they fire.
- Make the 2 offered factions in team select match for every player in
  a match: the server decides once and clients either read it directly
  (server's own instance) or request it over RPC, rather than each
  client rolling its own random pair.
- New MatchmakingClient autoload wires the main menu's CASUAL/RANKED
  buttons to the matchmaking API instead of connecting directly.

New matchmaking-api/ (FastAPI + Postgres, Docker Compose):
- Queue/match/stats/ranks endpoints. In-memory matchmaking queue in a
  single API process — no Redis until there's an actual reason to shard
  the queue across instances.
- Background loop forms a match once enough players are queued for a
  mode, assigns the first available registered game server.
- No real server pool yet: one dev server is auto-seeded from
  DEV_SEED_SERVER_IP/PORT; POST /servers/register exists for real
  servers to self-register later but nothing calls it yet.

Docs: CLAUDE.md and overview/tech.md updated to match — networking
checklist mostly checked off, matchmaking backend section rewritten to
describe what was actually built vs. the original Go/Redis plan, and
Current Tasks reordered around what's actually left (bot fill, real
server pool, ranked/MMR refinement, lag compensation).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

CLAUDE.md

@@ -14,19 +14,26 @@
 | `money.md` | Monetization strategy |
 | `structure.md` | Project file tree, scene graph, input map |
 
+Matchmaking API (`matchmaking-api/`, separate FastAPI + Postgres service, own
+`README.md`) is a second codebase alongside the Godot project — see its
+README for how to run/extend it.
+
 ## Completed
 
 1. **Server browser** — player name input, race toggles, server list (Trench Wars 0/32), JOIN button; stores name + race in `GameConfig` autoload
 2. **Main menu** — CASUAL / RANKED (disabled) buttons, callsign input, rank badge, QUIT; clears player state on load
 3. **In-game pause menu** — ESC / controller Start button toggles overlay; game keeps running; RESUME, SETTINGS (stub), SELECT TEAM (stub), QUIT TO MENU, QUIT TO DESKTOP
-4. **Team & ship selection** — shows on world load before player spawns; 2 races randomly offered per match; ship grid with sprites; player spawns with chosen ship after selection
+4. **Team & ship selection** — shows on world load before player spawns; 2 races randomly offered per match, decided once by the server so every player sees the same pair; ship grid with sprites; player spawns with chosen ship after selection
 5. **Real race art wired in** — Terran Republic, Mechanos Sovereignty, and Vorg Swarm each have their own 5-ship roster (Interceptor/Gunship/Bomber/Support/Heavy) with real sprites cropped from uploaded concept sheets (`assets/images/ships/<race>/`); placeholder `example_ships` removed
+6. **Multiplayer networking (movement + combat)** — ENet authoritative server; networked ship spawning with client-side prediction + server reconciliation for movement; server-authoritative bullets, health, death/respawn all broadcast to every peer (see `overview/tech.md`)
+7. **Matchmaking API + client wiring** — FastAPI + Postgres service (`matchmaking-api/`) for casual/ranked queueing; main menu CASUAL/RANKED buttons queue via the API, poll for a match, then connect to the assigned server. Currently only one dev server is registered (auto-seeded on API startup) — see Current Tasks
 
 ## Current Tasks
 
 - [ ] Asteroids and environment hazards
-- [ ] Bot fill for casual (minimum 7v7, bots fill empty slots — see `bots.md`)
+- [ ] Bot fill for casual (minimum 7v7, bots fill empty slots — see `bots.md`) — next logical step now that matchmaking works, since `CASUAL_TEAM_SIZE` is set low (1) for solo/duo testing on the assumption bots will pad real matches later
 - [ ] Sound effects (thrust, shoot, explosion, UI)
-- [ ] Multiplayer networking — ENet authoritative server (see `tech.md`)
+- [ ] Real game-server pool — servers self-register with the matchmaking API (`POST /servers/register` already exists, nothing calls it yet) instead of one hardcoded dev entry
 - [ ] Galaxy war meta / sector control for casual (see `multiplayer.md`)
-- [ ] Ranked matchmaking + MMR
+- [ ] Ranked matchmaking refinement — MMR-window widening, real account-linked MMR (currently a naive nearest-neighbor sort on a per-callsign stub); GodotSteam auth + VAC still not started
+- [ ] Lag compensation (basic rewind) — matters once testing moves beyond localhost

matchmaking-api/.env.example

@@ -0,0 +1,14 @@
+DATABASE_URL=postgresql+asyncpg://matchmaking:matchmaking@postgres:5432/matchmaking
+
+# Real-value targets per overview/bots.md (casual min 7v7) and overview/racesclasses.md (ranked 5v5).
+CASUAL_TEAM_SIZE=7
+RANKED_TEAM_SIZE=5
+
+# Registered on API startup so local matchmaking has somewhere to assign
+# players to before real game servers self-register via POST /servers/register.
+# This IP is handed straight to game CLIENTS to connect their ENet peer to —
+# clients run on the host, not in Docker, so it must be host-reachable
+# (127.0.0.1 for local dev), not a docker-internal alias like
+# host.docker.internal (that only resolves from inside the api container).
+DEV_SEED_SERVER_IP=127.0.0.1
+DEV_SEED_SERVER_PORT=7777

matchmaking-api/.gitignore

@@ -0,0 +1,4 @@
+__pycache__/
+*.pyc
+.env
+.venv/

matchmaking-api/Dockerfile

@@ -0,0 +1,10 @@
+FROM python:3.12-slim
+
+WORKDIR /app
+
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+COPY app ./app
+
+CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000"]

matchmaking-api/README.md

@@ -0,0 +1,81 @@
+# Spacewar Matchmaking API
+
+FastAPI service for matchmaking, stats, and ranks (chat planned — see below).
+One process, one Postgres database, no Redis: matchmaking tickets live
+in-memory in the API process, which is enough at this scale — add Redis
+later only if the API needs to run as more than one instance.
+
+## Run it
+
+```
+cp .env.example .env   # already done for local dev; edit if needed
+docker compose up -d
+```
+
+API is at `http://localhost:8100`, interactive docs at `/docs`. Postgres is
+exposed on host port `5433` (mapped from its usual `5432`, to avoid clashing
+with any other local Postgres) for local inspection.
+
+```
+docker compose down          # stop
+docker compose down -v       # stop + wipe the postgres volume
+```
+
+Code in `app/` is bind-mounted with `--reload`, so edits take effect without
+rebuilding the image. Rebuild (`docker compose up -d --build`) only when
+`requirements.txt` changes.
+
+## How matchmaking works right now
+
+- `POST /matchmaking/queue/join` `{callsign, mode, mmr?}` — creates the
+  player row if it doesn't exist yet, returns a `ticket_id`.
+- `GET /matchmaking/queue/status/{ticket_id}` — poll this; once matched it
+  returns the assigned server's `server_ip`/`server_port`/`team`.
+- `POST /matchmaking/queue/leave?ticket_id=...` — cancel a queued ticket.
+
+A background loop (`app/queue_manager.py`) runs every 2s, and once enough
+players are queued for a mode (`CASUAL_TEAM_SIZE`/`RANKED_TEAM_SIZE` × 2) it
+forms a match, splits them into two teams, and assigns the first available
+`GameServer` for that mode.
+
+There's no real game-server pool yet — one dev server is auto-seeded on API
+startup from `DEV_SEED_SERVER_IP`/`DEV_SEED_SERVER_PORT` (defaults to
+`127.0.0.1:7777`, i.e. a Godot server run on the host via
+`godot4 --headless --path spacewar -- --server`). That IP is handed straight
+to game clients to connect to, so it must be reachable from wherever the
+*client* runs, not the API container — `host.docker.internal` would resolve
+inside the api container but not on the client's machine, which is why this
+isn't a docker-internal address. Real servers should eventually call
+`POST /servers/register` on boot and periodically as a heartbeat — that
+endpoint exists but nothing calls it yet.
+
+## Client integration
+
+The Godot client is wired up (`spacewar/autoload/matchmaking_client.gd`):
+CASUAL/RANKED on the main menu calls `POST /matchmaking/queue/join`, polls
+`GET /matchmaking/queue/status/{ticket_id}` every 1.5s, and once `matched`
+connects `NetworkManager` directly to the returned `server_ip`/`server_port`.
+Point it at a non-default API with `godot4 ... -- --matchmaking-api=http://host:port`.
+
+## Adding a new domain (stats/ranks did this; chat will too)
+
+1. Add/extend a model in `app/models.py` if it needs its own table.
+2. Add request/response shapes to `app/schemas.py`.
+3. Add a router file under `app/routers/`, `include_router()` it in
+   `app/main.py`.
+
+Chat isn't scaffolded yet (no data model or requirements decided), but it
+fits the same shape — likely a WebSocket router using FastAPI's native
+support, in this same service.
+
+## Not set up yet, on purpose
+
+- **Migrations**: tables are created via `Base.metadata.create_all()` on
+  startup. Fine while the schema is still moving; switch to Alembic before
+  this holds real data.
+- **Auth**: `callsign` is the only player identity, matching the game
+  client's current state (no accounts yet). Real identity arrives with the
+  GodotSteam auth checklist item in `overview/tech.md`.
+- **Ranked MMR-window widening / bot-fill timeouts**: current matching is a
+  simple threshold (enough players queued → form a match). Refine once
+  there's real queue volume to tune against.

matchmaking-api/app/config.py

@@ -0,0 +1,14 @@
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+
+class Settings(BaseSettings):
+    model_config = SettingsConfigDict(env_file=".env", extra="ignore")
+
+    database_url: str
+    casual_team_size: int = 7
+    ranked_team_size: int = 5
+    dev_seed_server_ip: str = "127.0.0.1"
+    dev_seed_server_port: int = 7777
+
+
+settings = Settings()

matchmaking-api/app/database.py

@@ -0,0 +1,19 @@
+from collections.abc import AsyncGenerator
+
+from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
+from sqlalchemy.orm import DeclarativeBase
+
+from app.config import settings
+
+
+class Base(DeclarativeBase):
+    pass
+
+
+engine = create_async_engine(settings.database_url, echo=False)
+async_session = async_sessionmaker(engine, expire_on_commit=False)
+
+
+async def get_db() -> AsyncGenerator[AsyncSession, None]:
+    async with async_session() as session:
+        yield session

matchmaking-api/app/main.py

@@ -0,0 +1,58 @@
+import asyncio
+from contextlib import asynccontextmanager
+
+from fastapi import FastAPI
+from sqlalchemy import select
+
+from app.config import settings
+from app.database import Base, async_session, engine
+from app.models import GameServer, Mode, ServerStatus
+from app.queue_manager import queue_manager
+from app.routers import matchmaking, ranks, servers, stats
+
+
+async def _seed_dev_server() -> None:
+    async with async_session() as db:
+        for mode in (Mode.casual, Mode.ranked):
+            existing = (
+                await db.execute(
+                    select(GameServer).where(
+                        GameServer.ip == settings.dev_seed_server_ip,
+                        GameServer.port == settings.dev_seed_server_port,
+                        GameServer.mode == mode,
+                    )
+                )
+            ).scalars().first()
+            if existing is None:
+                db.add(
+                    GameServer(
+                        ip=settings.dev_seed_server_ip,
+                        port=settings.dev_seed_server_port,
+                        mode=mode,
+                        status=ServerStatus.available,
+                    )
+                )
+        await db.commit()
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    async with engine.begin() as conn:
+        await conn.run_sync(Base.metadata.create_all)
+    await _seed_dev_server()
+    matching_task = asyncio.create_task(queue_manager.run_matching_loop())
+    yield
+    matching_task.cancel()
+
+
+app = FastAPI(title="Spacewar Matchmaking API", lifespan=lifespan)
+
+app.include_router(matchmaking.router)
+app.include_router(stats.router)
+app.include_router(ranks.router)
+app.include_router(servers.router)
+
+
+@app.get("/health")
+async def health() -> dict:
+    return {"status": "ok"}

matchmaking-api/app/models.py

@@ -0,0 +1,67 @@
+import enum
+import uuid
+from datetime import datetime
+
+from sqlalchemy import DateTime, ForeignKey, Integer, String
+from sqlalchemy import Enum as SAEnum
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.database import Base
+
+
+class Mode(str, enum.Enum):
+    casual = "casual"
+    ranked = "ranked"
+
+
+class ServerStatus(str, enum.Enum):
+    available = "available"
+    full = "full"
+    offline = "offline"
+
+
+# No account/auth system yet (GodotSteam auth is still on the networking
+# checklist), so callsign is the identity key for now — same as the game
+# client itself, which only has a free-text name field today.
+class Player(Base):
+    __tablename__ = "players"
+
+    id: Mapped[uuid.UUID] = mapped_column(primary_key=True, default=uuid.uuid4)
+    callsign: Mapped[str] = mapped_column(String(32), unique=True, index=True)
+    mmr: Mapped[int] = mapped_column(Integer, default=1000)
+    wins: Mapped[int] = mapped_column(Integer, default=0)
+    losses: Mapped[int] = mapped_column(Integer, default=0)
+    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)
+
+
+class GameServer(Base):
+    __tablename__ = "game_servers"
+
+    id: Mapped[uuid.UUID] = mapped_column(primary_key=True, default=uuid.uuid4)
+    ip: Mapped[str] = mapped_column(String(255))
+    port: Mapped[int] = mapped_column(Integer)
+    mode: Mapped[Mode] = mapped_column(SAEnum(Mode))
+    status: Mapped[ServerStatus] = mapped_column(SAEnum(ServerStatus), default=ServerStatus.available)
+    last_heartbeat: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)
+
+
+class Match(Base):
+    __tablename__ = "matches"
+
+    id: Mapped[uuid.UUID] = mapped_column(primary_key=True, default=uuid.uuid4)
+    mode: Mapped[Mode] = mapped_column(SAEnum(Mode))
+    server_id: Mapped[uuid.UUID] = mapped_column(ForeignKey("game_servers.id"))
+    started_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)
+
+    players: Mapped[list["MatchPlayer"]] = relationship(back_populates="match")
+
+
+class MatchPlayer(Base):
+    __tablename__ = "match_players"
+
+    id: Mapped[uuid.UUID] = mapped_column(primary_key=True, default=uuid.uuid4)
+    match_id: Mapped[uuid.UUID] = mapped_column(ForeignKey("matches.id"))
+    player_id: Mapped[uuid.UUID] = mapped_column(ForeignKey("players.id"))
+    team: Mapped[int] = mapped_column(Integer)  # 0 or 1
+
+    match: Mapped["Match"] = relationship(back_populates="players")

matchmaking-api/app/queue_manager.py

@@ -0,0 +1,106 @@
+import asyncio
+import uuid
+from dataclasses import dataclass, field
+from datetime import datetime
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.config import settings
+from app.database import async_session
+from app.models import GameServer, Match, MatchPlayer, Mode, ServerStatus
+
+
+@dataclass
+class Ticket:
+    ticket_id: uuid.UUID
+    player_id: uuid.UUID
+    callsign: str
+    mode: Mode
+    mmr: int
+    queued_at: datetime = field(default_factory=datetime.utcnow)
+    status: str = "queued"  # queued | matched | cancelled
+    server_ip: str | None = None
+    server_port: int | None = None
+    team: int | None = None
+
+
+class QueueManager:
+    """In-memory matchmaking queue. No Redis: a single API process holds all
+    ticket state, which is fine at this scale and simpler to run — see
+    memory/spacewar_networking_plan for why Redis was deferred rather than
+    included from the start.
+    """
+
+    def __init__(self) -> None:
+        self._tickets: dict[uuid.UUID, Ticket] = {}
+        self._lock = asyncio.Lock()
+
+    async def join(self, player_id: uuid.UUID, callsign: str, mode: Mode, mmr: int) -> Ticket:
+        ticket = Ticket(ticket_id=uuid.uuid4(), player_id=player_id, callsign=callsign, mode=mode, mmr=mmr)
+        async with self._lock:
+            self._tickets[ticket.ticket_id] = ticket
+        return ticket
+
+    async def leave(self, ticket_id: uuid.UUID) -> bool:
+        async with self._lock:
+            ticket = self._tickets.get(ticket_id)
+            if ticket is None or ticket.status != "queued":
+                return False
+            ticket.status = "cancelled"
+            return True
+
+    def get(self, ticket_id: uuid.UUID) -> Ticket | None:
+        return self._tickets.get(ticket_id)
+
+    def _waiting(self, mode: Mode) -> list[Ticket]:
+        tickets = [t for t in self._tickets.values() if t.mode == mode and t.status == "queued"]
+        if mode == Mode.ranked:
+            # Simple MMR-sorted grouping. No widening-window-by-wait-time yet
+            # (real ranked matchmaking will want that) — nearest-neighbor by
+            # mmr is a reasonable placeholder until ranked queue volume
+            # exists to tune against.
+            tickets.sort(key=lambda t: t.mmr)
+        else:
+            tickets.sort(key=lambda t: t.queued_at)
+        return tickets
+
+    async def _try_form_match(self, mode: Mode, team_size: int, db: AsyncSession) -> None:
+        required = team_size * 2
+        async with self._lock:
+            waiting = self._waiting(mode)
+            if len(waiting) < required:
+                return
+            group = waiting[:required]
+
+            server = (
+                await db.execute(
+                    select(GameServer).where(GameServer.mode == mode, GameServer.status == ServerStatus.available)
+                )
+            ).scalars().first()
+            if server is None:
+                return  # no server free this cycle; leave everyone queued and retry next tick
+
+            match = Match(mode=mode, server_id=server.id)
+            db.add(match)
+            await db.flush()
+
+            for i, ticket in enumerate(group):
+                team = i % 2
+                db.add(MatchPlayer(match_id=match.id, player_id=ticket.player_id, team=team))
+                ticket.status = "matched"
+                ticket.server_ip = server.ip
+                ticket.server_port = server.port
+                ticket.team = team
+
+            await db.commit()
+
+    async def run_matching_loop(self) -> None:
+        while True:
+            await asyncio.sleep(2)
+            async with async_session() as db:
+                await self._try_form_match(Mode.casual, settings.casual_team_size, db)
+                await self._try_form_match(Mode.ranked, settings.ranked_team_size, db)
+
+
+queue_manager = QueueManager()

matchmaking-api/app/routers/matchmaking.py

@@ -0,0 +1,53 @@
+import uuid
+
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.models import Mode, Player
+from app.queue_manager import queue_manager
+from app.schemas import QueueJoinRequest, QueueJoinResponse, QueueStatusResponse
+
+router = APIRouter(prefix="/matchmaking", tags=["matchmaking"])
+
+
+async def _get_or_create_player(db: AsyncSession, callsign: str) -> Player:
+    player = (await db.execute(select(Player).where(Player.callsign == callsign))).scalars().first()
+    if player is None:
+        player = Player(callsign=callsign)
+        db.add(player)
+        await db.commit()
+        await db.refresh(player)
+    return player
+
+
+@router.post("/queue/join", response_model=QueueJoinResponse)
+async def join_queue(req: QueueJoinRequest, db: AsyncSession = Depends(get_db)) -> QueueJoinResponse:
+    player = await _get_or_create_player(db, req.callsign)
+    mmr = req.mmr if req.mode == Mode.ranked and req.mmr is not None else player.mmr
+
+    ticket = await queue_manager.join(player.id, player.callsign, req.mode, mmr)
+    return QueueJoinResponse(ticket_id=ticket.ticket_id, status=ticket.status)
+
+
+@router.post("/queue/leave")
+async def leave_queue(ticket_id: uuid.UUID) -> dict:
+    ok = await queue_manager.leave(ticket_id)
+    if not ok:
+        raise HTTPException(status_code=404, detail="Ticket not found or already resolved")
+    return {"status": "cancelled"}
+
+
+@router.get("/queue/status/{ticket_id}", response_model=QueueStatusResponse)
+async def queue_status(ticket_id: uuid.UUID) -> QueueStatusResponse:
+    ticket = queue_manager.get(ticket_id)
+    if ticket is None:
+        raise HTTPException(status_code=404, detail="Ticket not found")
+    return QueueStatusResponse(
+        ticket_id=ticket.ticket_id,
+        status=ticket.status,
+        server_ip=ticket.server_ip,
+        server_port=ticket.server_port,
+        team=ticket.team,
+    )

matchmaking-api/app/routers/ranks.py

@@ -0,0 +1,35 @@
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.models import Player
+
+router = APIRouter(prefix="/ranks", tags=["ranks"])
+
+# Mirrors RANK_DATA in spacewar/menu/main_menu.gd — keep the tier names (and
+# ideally thresholds) in sync if either side changes.
+_TIERS: list[tuple[int, str]] = [
+    (0, "CADET"),
+    (1000, "PILOT"),
+    (1400, "ACE"),
+    (1800, "COMMANDER"),
+    (2200, "ADMIRAL"),
+    (2600, "LEGEND"),
+]
+
+
+def _tier_for(mmr: int) -> str:
+    tier = _TIERS[0][1]
+    for threshold, name in _TIERS:
+        if mmr >= threshold:
+            tier = name
+    return tier
+
+
+@router.get("/{callsign}")
+async def get_rank(callsign: str, db: AsyncSession = Depends(get_db)) -> dict:
+    player = (await db.execute(select(Player).where(Player.callsign == callsign))).scalars().first()
+    if player is None:
+        raise HTTPException(status_code=404, detail="Player not found")
+    return {"callsign": player.callsign, "mmr": player.mmr, "rank": _tier_for(player.mmr)}

matchmaking-api/app/routers/servers.py

@@ -0,0 +1,44 @@
+from datetime import datetime
+
+from fastapi import APIRouter, Depends
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.models import GameServer, ServerStatus
+from app.schemas import ServerRegisterRequest
+
+router = APIRouter(prefix="/servers", tags=["servers"])
+
+
+# Real game servers should call this on boot and periodically (heartbeat) once
+# NetworkManager grows that integration. Until then, a dev server is seeded
+# on API startup (see main.py) from DEV_SEED_SERVER_IP/PORT so matchmaking is
+# testable end-to-end without it.
+@router.post("/register")
+async def register_server(req: ServerRegisterRequest, db: AsyncSession = Depends(get_db)) -> dict:
+    existing = (
+        await db.execute(select(GameServer).where(GameServer.ip == req.ip, GameServer.port == req.port, GameServer.mode == req.mode))
+    ).scalars().first()
+    if existing:
+        existing.status = ServerStatus.available
+        existing.last_heartbeat = datetime.utcnow()
+    else:
+        db.add(GameServer(ip=req.ip, port=req.port, mode=req.mode, status=ServerStatus.available))
+    await db.commit()
+    return {"status": "registered"}
+
+
+@router.get("")
+async def list_servers(db: AsyncSession = Depends(get_db)) -> list[dict]:
+    servers = (await db.execute(select(GameServer))).scalars().all()
+    return [
+        {
+            "ip": s.ip,
+            "port": s.port,
+            "mode": s.mode,
+            "status": s.status,
+            "last_heartbeat": s.last_heartbeat,
+        }
+        for s in servers
+    ]

matchmaking-api/app/routers/stats.py

@@ -0,0 +1,17 @@
+from fastapi import APIRouter, Depends, HTTPException
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.database import get_db
+from app.models import Player
+from app.schemas import PlayerStatsResponse
+
+router = APIRouter(prefix="/stats", tags=["stats"])
+
+
+@router.get("/{callsign}", response_model=PlayerStatsResponse)
+async def get_stats(callsign: str, db: AsyncSession = Depends(get_db)) -> PlayerStatsResponse:
+    player = (await db.execute(select(Player).where(Player.callsign == callsign))).scalars().first()
+    if player is None:
+        raise HTTPException(status_code=404, detail="Player not found")
+    return PlayerStatsResponse(callsign=player.callsign, mmr=player.mmr, wins=player.wins, losses=player.losses)

matchmaking-api/app/schemas.py

@@ -0,0 +1,37 @@
+import uuid
+
+from pydantic import BaseModel
+
+from app.models import Mode
+
+
+class QueueJoinRequest(BaseModel):
+    callsign: str
+    mode: Mode
+    mmr: int | None = None  # ignored for casual; defaults to the player's stored mmr for ranked
+
+
+class QueueJoinResponse(BaseModel):
+    ticket_id: uuid.UUID
+    status: str
+
+
+class QueueStatusResponse(BaseModel):
+    ticket_id: uuid.UUID
+    status: str
+    server_ip: str | None = None
+    server_port: int | None = None
+    team: int | None = None
+
+
+class ServerRegisterRequest(BaseModel):
+    ip: str
+    port: int
+    mode: Mode
+
+
+class PlayerStatsResponse(BaseModel):
+    callsign: str
+    mmr: int
+    wins: int
+    losses: int

matchmaking-api/docker-compose.yml

@@ -0,0 +1,35 @@
+services:
+  postgres:
+    image: postgres:16-alpine
+    environment:
+      POSTGRES_USER: matchmaking
+      POSTGRES_PASSWORD: matchmaking
+      POSTGRES_DB: matchmaking
+    ports:
+      - "5433:5432"
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+    healthcheck:
+      test: ["CMD-SHELL", "pg_isready -U matchmaking"]
+      interval: 5s
+      timeout: 5s
+      retries: 5
+
+  api:
+    build: .
+    env_file: .env
+    ports:
+      - "8100:8000"
+    depends_on:
+      postgres:
+        condition: service_healthy
+    extra_hosts:
+      # Lets the container reach a Godot dev server running on the host
+      # (Linux Docker Engine doesn't resolve host.docker.internal by default).
+      - "host.docker.internal:host-gateway"
+    volumes:
+      - ./app:/app/app
+    command: ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8000", "--reload"]
+
+volumes:
+  postgres_data:

matchmaking-api/requirements.txt

@@ -0,0 +1,5 @@
+fastapi==0.115.0
+uvicorn[standard]==0.32.0
+sqlalchemy==2.0.36
+asyncpg==0.30.0
+pydantic-settings==2.6.1

overview/tech.md

@@ -55,19 +55,30 @@ func send_input(dir: Vector2, firing: bool) -> void:
 
 ### Matchmaking Backend
 
-| Component | Tech |
-|-----------|------|
-| API Server | Go or Node.js |
-| Queue / State | Redis |
-| Database (accounts, ranks) | PostgreSQL |
-| Hosting | VPS (Hetzner / DigitalOcean) or self-hosted |
+Built — see `matchmaking-api/README.md` for how to run it. Actual stack
+diverged from the original plan below:
 
-**Flow:**
-1. Client sends "find match" with MMR + mode
-2. Backend queues player, finds lobby within MMR range
-3. Lobby full → backend assigns a game server
-4. Backend sends client the server IP + session token
-5. Client connects directly to game server
+| Component | Planned | Actual |
+|-----------|---------|--------|
+| API Server | Go or Node.js | **FastAPI (Python)** — I/O-bound queue/CRUD logic, not a latency-critical hot path, so dev velocity won over raw throughput |
+| Queue / State | Redis | **In-memory in the API process** — no Redis; revisit only if the API needs to run as more than one instance |
+| Database (accounts, ranks) | PostgreSQL | PostgreSQL, as planned |
+| Hosting | VPS (Hetzner / DigitalOcean) or self-hosted | Not deployed — local Docker Compose only so far |
+
+**Flow (as built):**
+1. Client sends `POST /matchmaking/queue/join` with callsign + mode
+2. Backend queues the ticket; a background loop forms a match once enough
+   players are queued for that mode
+3. Match forms → backend assigns the first available registered `GameServer`
+   for that mode
+4. Client polls `GET /matchmaking/queue/status/{ticket}` until `matched`,
+   then connects directly to the returned server IP/port
+
+Not yet built: session tokens (server IP/port are handed back unauthenticated
+— fine for local dev, not for a real deployment), and a real server pool —
+only one dev server is registered right now (auto-seeded on API startup);
+`POST /servers/register` exists for real servers to self-register/heartbeat
+but nothing calls it yet.
 
 ### Steam Integration
 
@@ -79,11 +90,11 @@ func send_input(dir: Vector2, firing: bool) -> void:
 
 ## Networking Checklist
 
-- [ ] Godot ENet server/client setup
-- [ ] Player input RPC structure
-- [ ] Position sync with interpolation
-- [ ] Ship class registration per peer
-- [ ] Server-authoritative health/death
-- [ ] Matchmaking API (queue + lobby assignment)
+- [x] Godot ENet server/client setup
+- [x] Player input RPC structure
+- [x] Position sync with interpolation
+- [x] Ship class registration per peer
+- [x] Server-authoritative health/death
+- [x] Matchmaking API (queue + lobby assignment) — client wired end-to-end; real server pool and ranked MMR-window widening still open, see Current Tasks in `CLAUDE.md`
 - [ ] GodotSteam auth + VAC
 - [ ] Lag compensation (basic rewind)

spacewar/autoload/game_config.gd

@@ -1,7 +1,5 @@
 extends Node
 
-signal team_selected
-
 # Ship movement
 var ship_thrust: float = 250.0
 var ship_max_speed: float = 300.0
@@ -21,12 +19,9 @@ var bullet_damage: int = 40
 var ship_bounce_restitution: float = 0.45
 var ship_collision_damage_scale: float = 0.064
 
-# Set before entering a game
+# Locally-remembered callsign, pre-fills the name field on the menu.
+# Race/ship/speed are per-peer now — see PlayerRegistry.
 var player_name: String = ""
-var player_race: int = 0
-var player_ship_path: String = ""
-var player_ship_scale: float = 1.0
-var player_ship_speed_factor: float = 1.0
 
 # Current map's play area, in world coordinates. Set by world.gd on load.
 var world_bounds: Rect2 = Rect2(0, 0, 1152, 648)

spacewar/autoload/matchmaking_client.gd

@@ -0,0 +1,125 @@
+extends Node
+
+# Talks to the FastAPI matchmaking service (see /matchmaking-api). No client
+# library — plain HTTPRequest per call, since traffic here is low-frequency
+# (one join, then a poll every ~1.5s) and each request gets its own
+# short-lived HTTPRequest node so calls never collide with each other.
+
+signal search_started
+signal match_found(server_ip: String, server_port: int)
+signal search_failed(reason: String)
+
+const POLL_INTERVAL := 1.5
+
+var base_url: String = "http://127.0.0.1:8100"
+
+var _ticket_id: String = ""
+var _poll_timer: Timer
+var _searching: bool = false
+
+
+func _ready() -> void:
+	for arg in OS.get_cmdline_user_args():
+		if arg.begins_with("--matchmaking-api="):
+			base_url = arg.substr("--matchmaking-api=".length())
+
+	_poll_timer = Timer.new()
+	_poll_timer.wait_time = POLL_INTERVAL
+	_poll_timer.one_shot = false
+	_poll_timer.timeout.connect(_poll_status)
+	add_child(_poll_timer)
+
+
+func start_matchmaking(callsign: String, mode: String) -> void:
+	if _searching:
+		return
+	_searching = true
+	search_started.emit()
+
+	var result := await _request("POST", "/matchmaking/queue/join", {
+		"callsign": callsign,
+		"mode": mode,
+	})
+
+	if not _searching:
+		return  # cancelled while the join request was in flight
+
+	if result.get("code", 0) != 200:
+		_fail("Couldn't reach matchmaking service")
+		return
+
+	_ticket_id = result.body.ticket_id
+	_poll_timer.start()
+
+
+func cancel_matchmaking() -> void:
+	if not _searching:
+		return
+	_searching = false
+	_poll_timer.stop()
+	if _ticket_id != "":
+		_request("POST", "/matchmaking/queue/leave?ticket_id=" + _ticket_id, null)
+	_ticket_id = ""
+
+
+func _poll_status() -> void:
+	if _ticket_id == "":
+		return
+	var result := await _request("GET", "/matchmaking/queue/status/" + _ticket_id, null)
+
+	if not _searching:
+		return  # cancelled while the poll was in flight
+
+	if result.get("code", 0) != 200:
+		_fail("Lost contact with matchmaking service")
+		return
+
+	var status: String = result.body.status
+	if status == "matched":
+		_poll_timer.stop()
+		_searching = false
+		var ip: String = result.body.server_ip
+		var port: int = result.body.server_port
+		_ticket_id = ""
+		match_found.emit(ip, port)
+	elif status == "cancelled":
+		_poll_timer.stop()
+		_searching = false
+		_ticket_id = ""
+		_fail("Queue ticket was cancelled")
+	# else "queued": keep polling
+
+
+func _fail(reason: String) -> void:
+	_poll_timer.stop()
+	_searching = false
+	_ticket_id = ""
+	search_failed.emit(reason)
+
+
+# Returns {"code": int, "body": Dictionary} — "code" is 0 if the request
+# itself couldn't even be sent (e.g. malformed URL), not an HTTP status.
+func _request(method: String, path: String, body) -> Dictionary:
+	var http := HTTPRequest.new()
+	add_child(http)
+
+	var headers := PackedStringArray()
+	var body_str := ""
+	if body != null:
+		headers.append("Content-Type: application/json")
+		body_str = JSON.stringify(body)
+
+	var http_method := HTTPClient.METHOD_GET if method == "GET" else HTTPClient.METHOD_POST
+	var err := http.request(base_url + path, headers, http_method, body_str)
+	if err != OK:
+		http.queue_free()
+		return {"code": 0, "body": null}
+
+	var response = await http.request_completed
+	http.queue_free()
+
+	var response_code: int = response[1]
+	var response_body: PackedByteArray = response[3]
+	var text := response_body.get_string_from_utf8()
+	var parsed = JSON.parse_string(text) if text != "" else null
+	return {"code": response_code, "body": parsed}

spacewar/autoload/matchmaking_client.gd.uid

@@ -0,0 +1 @@
+uid://d26rs8apbu84y

spacewar/autoload/network_manager.gd

@@ -0,0 +1,92 @@
+extends Node
+
+signal connection_succeeded
+signal connection_failed
+signal peer_joined(peer_id: int)
+signal peer_left(peer_id: int)
+
+const DEFAULT_PORT := 7777
+const MAX_PLAYERS := 50  # covers 25v25 casual
+
+var is_server: bool = false
+var target_ip: String = "127.0.0.1"
+
+
+func _ready() -> void:
+	multiplayer.peer_connected.connect(_on_peer_connected)
+	multiplayer.peer_disconnected.connect(_on_peer_disconnected)
+	multiplayer.connected_to_server.connect(_on_connected_to_server)
+	multiplayer.connection_failed.connect(_on_connection_failed)
+	multiplayer.server_disconnected.connect(_on_server_disconnected)
+
+	_apply_cmdline_args()
+
+
+# Dev-only bootstrap: `-- --server` runs this instance as a dedicated headless
+# server; `-- --connect=<ip>` overrides the default join target for clients.
+func _apply_cmdline_args() -> void:
+	var args := OS.get_cmdline_user_args()
+	for arg in args:
+		if arg.begins_with("--connect="):
+			target_ip = arg.substr("--connect=".length())
+	if args.has("--server"):
+		host_server(DEFAULT_PORT)
+		await get_tree().process_frame
+		get_tree().change_scene_to_file("res://world/world.tscn")
+
+
+func host_server(port: int = DEFAULT_PORT) -> void:
+	var peer := ENetMultiplayerPeer.new()
+	var err := peer.create_server(port, MAX_PLAYERS)
+	if err != OK:
+		push_error("[NetworkManager] Failed to host on port %d: %s" % [port, err])
+		return
+	multiplayer.multiplayer_peer = peer
+	is_server = true
+	print("[NetworkManager] Hosting on port %d" % port)
+
+
+func disconnect_from_game() -> void:
+	if multiplayer.multiplayer_peer != null:
+		multiplayer.multiplayer_peer.close()
+		multiplayer.multiplayer_peer = null
+	is_server = false
+
+
+func join_server(ip: String, port: int = DEFAULT_PORT) -> void:
+	var peer := ENetMultiplayerPeer.new()
+	var err := peer.create_client(ip, port)
+	if err != OK:
+		push_error("[NetworkManager] Failed to start client toward %s:%d: %s" % [ip, port, err])
+		connection_failed.emit()
+		return
+	multiplayer.multiplayer_peer = peer
+	is_server = false
+	print("[NetworkManager] Connecting to %s:%d..." % [ip, port])
+
+
+func _on_peer_connected(peer_id: int) -> void:
+	print("[NetworkManager] Peer connected: %d" % peer_id)
+	peer_joined.emit(peer_id)
+
+
+func _on_peer_disconnected(peer_id: int) -> void:
+	print("[NetworkManager] Peer disconnected: %d" % peer_id)
+	peer_left.emit(peer_id)
+
+
+func _on_connected_to_server() -> void:
+	print("[NetworkManager] Connected, local peer id: %d" % multiplayer.get_unique_id())
+	connection_succeeded.emit()
+
+
+func _on_connection_failed() -> void:
+	print("[NetworkManager] Connection failed")
+	multiplayer.multiplayer_peer = null
+	connection_failed.emit()
+
+
+func _on_server_disconnected() -> void:
+	print("[NetworkManager] Server disconnected")
+	multiplayer.multiplayer_peer = null
+	connection_failed.emit()

spacewar/autoload/network_manager.gd.uid

@@ -0,0 +1 @@
+uid://cwfpdpotmiial

spacewar/autoload/player_registry.gd

@@ -0,0 +1,72 @@
+extends Node
+
+# Server-authoritative registry of every connected peer's chosen loadout,
+# replicated to all clients so everyone knows everyone's race/ship, not just
+# their own.
+
+signal loadout_updated(peer_id: int)
+signal player_removed(peer_id: int)
+
+var players: Dictionary = {}  # peer_id -> {name, race, ship_path, ship_scale, ship_speed_factor}
+
+
+func _ready() -> void:
+	NetworkManager.peer_left.connect(_on_peer_left)
+
+
+func get_local_id() -> int:
+	return multiplayer.get_unique_id()
+
+
+func get_info(peer_id: int) -> Dictionary:
+	return players.get(peer_id, {})
+
+
+func submit_local_loadout(player_name: String, race: int, ship_path: String, ship_scale: float, ship_speed_factor: float) -> void:
+	submit_loadout.rpc(player_name, race, ship_path, ship_scale, ship_speed_factor)
+
+
+# Client -> server (and locally to self via call_local). Server then relays
+# the new loadout to everyone else, and backfills the newcomer with everyone
+# else's already-known loadout.
+@rpc("any_peer", "call_local", "reliable")
+func submit_loadout(player_name: String, race: int, ship_path: String, ship_scale: float, ship_speed_factor: float) -> void:
+	var sender_id := multiplayer.get_remote_sender_id()
+	if sender_id == 0:
+		sender_id = multiplayer.get_unique_id()
+
+	if not multiplayer.is_server():
+		_store(sender_id, player_name, race, ship_path, ship_scale, ship_speed_factor)
+		return
+
+	for peer_id in multiplayer.get_peers():
+		if peer_id != sender_id:
+			_receive_loadout.rpc_id(peer_id, sender_id, player_name, race, ship_path, ship_scale, ship_speed_factor)
+	for peer_id in players:
+		if peer_id != sender_id:
+			var info: Dictionary = players[peer_id]
+			_receive_loadout.rpc_id(sender_id, peer_id, info.name, info.race, info.ship_path, info.ship_scale, info.ship_speed_factor)
+
+	_store(sender_id, player_name, race, ship_path, ship_scale, ship_speed_factor)
+
+
+@rpc("authority", "call_remote", "reliable")
+func _receive_loadout(peer_id: int, player_name: String, race: int, ship_path: String, ship_scale: float, ship_speed_factor: float) -> void:
+	_store(peer_id, player_name, race, ship_path, ship_scale, ship_speed_factor)
+
+
+func _store(peer_id: int, player_name: String, race: int, ship_path: String, ship_scale: float, ship_speed_factor: float) -> void:
+	players[peer_id] = {
+		"name": player_name,
+		"race": race,
+		"ship_path": ship_path,
+		"ship_scale": ship_scale,
+		"ship_speed_factor": ship_speed_factor,
+	}
+	print("[PlayerRegistry] peer %d loadout: %s" % [peer_id, players[peer_id]])
+	loadout_updated.emit(peer_id)
+
+
+func _on_peer_left(peer_id: int) -> void:
+	if players.erase(peer_id):
+		player_removed.emit(peer_id)

spacewar/autoload/player_registry.gd.uid

@@ -0,0 +1 @@
+uid://ccta6qxoqmoh8

spacewar/menu/main_menu.gd

@@ -3,6 +3,8 @@ extends Control
 var _name_input: LineEdit
 var _casual_btn: Button
 var _ranked_btn: Button
+var _status_lbl: Label
+var _connecting: bool = false
 
 const RANK_DATA := [
 	{"label": "CADET",     "color": Color(0.72, 0.48, 0.22)},
@@ -16,9 +18,11 @@ const CURRENT_RANK := 0  # placeholder until backend exists
 
 
 func _ready() -> void:
-	GameConfig.player_race = 0
-	GameConfig.player_ship_path = ""
 	_build_ui()
+	NetworkManager.connection_succeeded.connect(_on_connected)
+	NetworkManager.connection_failed.connect(_on_connect_failed)
+	MatchmakingClient.match_found.connect(_on_match_found)
+	MatchmakingClient.search_failed.connect(_on_search_failed)
 
 
 func _build_ui() -> void:
@@ -134,6 +138,17 @@ func _add_play_section() -> void:
 	_name_input.text_changed.connect(_on_name_changed)
 	add_child(_name_input)
 
+	_status_lbl = Label.new()
+	_status_lbl.text = ""
+	_status_lbl.set_anchor_and_offset(SIDE_LEFT,   0.0, LEFT_X)
+	_status_lbl.set_anchor_and_offset(SIDE_TOP,    0.0, TOP_Y + BTN_H + 68.0)
+	_status_lbl.set_anchor_and_offset(SIDE_RIGHT,  0.0, LEFT_X + BTN_W * 2.0 + GAP)
+	_status_lbl.set_anchor_and_offset(SIDE_BOTTOM, 0.0, TOP_Y + BTN_H + 92.0)
+	_status_lbl.horizontal_alignment = HORIZONTAL_ALIGNMENT_CENTER
+	_status_lbl.add_theme_font_size_override("font_size", 13)
+	_status_lbl.add_theme_color_override("font_color", Color(0.85, 0.4, 0.4))
+	add_child(_status_lbl)
+
 	_update_play_buttons()
 
 
@@ -322,17 +337,49 @@ func _on_name_changed(_text: String) -> void:
 
 
 func _update_play_buttons() -> void:
-	var ok := not _name_input.text.strip_edges().is_empty()
+	var ok := not _name_input.text.strip_edges().is_empty() and not _connecting
 	_casual_btn.disabled = not ok
 	_ranked_btn.disabled = true
 
 
 func _on_play_casual() -> void:
-	GameConfig.player_name = _name_input.text.strip_edges()
-	get_tree().change_scene_to_file("res://world/world.tscn")
+	_start_match("casual")
 
 
 func _on_play_ranked() -> void:
+	_start_match("ranked")
+
+
+func _start_match(mode: String) -> void:
+	if _connecting:
+		return
 	GameConfig.player_name = _name_input.text.strip_edges()
-	GameConfig.player_race = 1  # TODO: race selection screen
+	_connecting = true
+	_status_lbl.add_theme_color_override("font_color", Color(0.6, 0.72, 0.86))
+	_status_lbl.text = "Searching for a match..."
+	_update_play_buttons()
+	MatchmakingClient.start_matchmaking(GameConfig.player_name, mode)
+
+
+func _on_match_found(server_ip: String, server_port: int) -> void:
+	_status_lbl.text = "Match found — connecting..."
+	NetworkManager.join_server(server_ip, server_port)
+
+
+func _on_connected() -> void:
 	get_tree().change_scene_to_file("res://world/world.tscn")
+
+
+func _on_connect_failed() -> void:
+	_connecting = false
+	_status_lbl.add_theme_color_override("font_color", Color(0.85, 0.4, 0.4))
+	_status_lbl.text = "Connection failed — is the game server reachable?"
+	_update_play_buttons()
+
+
+func _on_search_failed(reason: String) -> void:
+	_connecting = false
+	_status_lbl.add_theme_color_override("font_color", Color(0.85, 0.4, 0.4))
+	_status_lbl.text = "Matchmaking failed: %s" % reason
+	_update_play_buttons()
+	_update_play_buttons()

spacewar/menu/pause_menu.gd

@@ -117,6 +117,7 @@ func _flat(col: Color, radius: int = 0) -> StyleBoxFlat:
 
 
 func _on_quit_to_menu() -> void:
+	NetworkManager.disconnect_from_game()
 	get_tree().change_scene_to_file("res://menu/main_menu.tscn")
 
 

spacewar/menu/team_select.gd

@@ -1,4 +1,5 @@
 extends CanvasLayer
+class_name TeamSelect
 
 # Movement speed factor by role, shared across all 3 races so e.g. every
 # race's Interceptor moves at the same speed as every other race's.
@@ -116,21 +117,41 @@ const ROW_IMG   := 95.0
 
 var _root: Control
 var _content: Control
+var _loading_lbl: Label
 var _offered: Array = []
 var _chosen_race: Dictionary = {}
 
 
 func _ready() -> void:
 	layer = 20
-	_offered = _pick_two_races()
 	_build_root()
+
+	# The 2 offered races must be the same for every player in the match, not
+	# independently randomized per client — the server decides once (see
+	# World.decide_offered_races()) and every client either asks for it
+	# (real remote peers) or reads it directly (the server's own instance,
+	# no round-trip needed since it's the same process).
+	var world := get_node("/root/World")
+	if multiplayer.is_server():
+		offer_races(world.decide_offered_races())
+	else:
+		world.request_offered_races.rpc_id(1)
+
+
+# Called once this client knows which 2 races (by id) the match is offering.
+func offer_races(race_ids: Array) -> void:
+	if _loading_lbl:
+		_loading_lbl.queue_free()
+		_loading_lbl = null
+	_offered = race_ids.map(func(id): return _race_by_id(id))
 	_show_race_selection()
 
 
-func _pick_two_races() -> Array:
-	var pool := RACES.duplicate()
-	pool.shuffle()
-	return [pool[0], pool[1]]
+func _race_by_id(id: int) -> Dictionary:
+	for race in RACES:
+		if race.id == id:
+			return race
+	return RACES[0]
 
 
 func _build_root() -> void:
@@ -144,6 +165,9 @@ func _build_root() -> void:
 	overlay.mouse_filter = Control.MOUSE_FILTER_STOP
 	_root.add_child(overlay)
 
+	_loading_lbl = _label(_root, "LOADING MATCH...", 20, Color(0.5, 0.6, 0.75),
+		0, 380, 1280, 420, HORIZONTAL_ALIGNMENT_CENTER)
+
 
 func _swap_content() -> Control:
 	if _content:
@@ -179,7 +203,6 @@ func _show_race_selection() -> void:
 
 func _on_race_chosen(race: Dictionary) -> void:
 	_chosen_race = race
-	GameConfig.player_race = race.id
 	_show_ship_selection()
 
 
@@ -203,10 +226,9 @@ func _show_ship_selection() -> void:
 
 
 func _on_ship_chosen(ship: Dictionary) -> void:
-	GameConfig.player_ship_path = ship.path
-	GameConfig.player_ship_scale = ship.scale
-	GameConfig.player_ship_speed_factor = ship.speed_factor
-	GameConfig.team_selected.emit()
+	PlayerRegistry.submit_local_loadout(
+		GameConfig.player_name, _chosen_race.id, ship.path, ship.scale, ship.speed_factor
+	)
 	queue_free()
 
 
@@ -346,7 +368,7 @@ func _make_ship_row(ship: Dictionary, accent: Color) -> Button:
 
 func _label(parent: Control, text: String, font_size: int, color: Color,
 		x1: float, y1: float, x2: float, y2: float,
-		align: HorizontalAlignment = HORIZONTAL_ALIGNMENT_LEFT) -> void:
+		align: HorizontalAlignment = HORIZONTAL_ALIGNMENT_LEFT) -> Label:
 	var lbl := Label.new()
 	lbl.text = text
 	lbl.horizontal_alignment = align
@@ -355,6 +377,7 @@ func _label(parent: Control, text: String, font_size: int, color: Color,
 	lbl.add_theme_color_override("font_color", color)
 	_place(lbl, x1, y1, x2, y2)
 	parent.add_child(lbl)
+	return lbl
 
 
 func _place(node: Control, x1: float, y1: float, x2: float, y2: float) -> void:

spacewar/project.godot

@@ -18,12 +18,14 @@ config/icon="res://assets/icon.svg"
 [autoload]
 
 GameConfig="*res://autoload/game_config.gd"
+NetworkManager="*res://autoload/network_manager.gd"
+PlayerRegistry="*res://autoload/player_registry.gd"
+MatchmakingClient="*res://autoload/matchmaking_client.gd"
 
 [display]
 
-window/size/viewport_width=2560
-window/size/viewport_height=1440
-window/size/mode=3
+window/size/viewport_width=1280
+window/size/viewport_height=800
 window/stretch/mode="canvas_items"
 window/stretch/aspect="expand"
 

spacewar/ships/bullet.gd

@@ -1,19 +1,26 @@
 extends Area2D
 
+# Set by World._spawn_bullet() before this node enters the tree.
 var velocity: Vector2 = Vector2.ZERO
-var source: Node = null
+var source_peer_id: int = 0
 
+# Only the server detects hits and despawns bullets — that's replicated to
+# every client automatically since bullets are spawned via BulletSpawner.
+# Movement itself stays local on every peer (deterministic constant-velocity
+# simulation from the replicated spawn state, no further sync needed).
 func _ready() -> void:
+	if multiplayer.is_server():
 		body_entered.connect(_on_body_entered)
 
 func _process(delta: float) -> void:
 	global_position += velocity * delta
+	if multiplayer.is_server():
 		var bounds = GameConfig.world_bounds.grow(64.0)
 		if not bounds.has_point(global_position):
 			queue_free()
 
 func _on_body_entered(body: Node) -> void:
-	if body == source:
+	if body.get("peer_id") == source_peer_id:
 		return
 	if body.has_method("take_damage"):
 		body.take_damage(GameConfig.bullet_damage)

spacewar/ships/ship.tscn

@@ -18,7 +18,7 @@ texture = ExtResource("2_epypp")
 [node name="VisibleOnScreenNotifier2D" type="VisibleOnScreenNotifier2D" parent="." unique_id=1504818491]
 
 [node name="Camera2D" type="Camera2D" parent="."]
-current = true
+current = false
 rotating = false
 position_smoothing_enabled = true
 position_smoothing_speed = 8.0

spacewar/ships/ship_movement.gd

@@ -1,39 +1,89 @@
 extends CharacterBody2D
 
-const BULLET_SCENE = preload("res://ships/bullet.tscn")
+# Set by World._spawn_ship() before this node enters the tree.
+var peer_id: int = 0
 
 var _fire_cooldown: float = 0.0
 var health: int = 0
 var _dead: bool = false
 var _invincible: bool = false
 var _invincible_timer: float = 0.0
+var _ship_speed_factor: float = 1.0
+
+var _is_owner: bool = false
+var _fixed_delta: float = 1.0 / 60.0
+
+# Owner-side prediction: inputs sent to the server but not yet acknowledged,
+# replayed on top of the server's authoritative state on correction.
+const MAX_PENDING_INPUTS := 180
+var _input_tick: int = 0
+var _pending_inputs: Array = []
+
+# Server-side: queued inputs received from the owning peer, plus the last
+# processed one (reused when the queue runs dry, e.g. a dropped packet).
+var _remote_inputs: Array = []
+var _last_remote_input: Dictionary = {"up": false, "down": false, "left": false, "right": false, "shoot": false}
+var _last_processed_tick: int = 0
+
+# Remote (non-owner, non-server) clients only ever interpolate toward the
+# last couple of authoritative snapshots broadcast by the server.
+var _interp_from_pos: Vector2
+var _interp_from_rot: float = 0.0
+var _interp_to_pos: Vector2
+var _interp_to_rot: float = 0.0
+var _interp_elapsed: float = 0.0
+
 
 func _ready() -> void:
-	if GameConfig.player_ship_path.is_empty():
+	_fixed_delta = 1.0 / Engine.physics_ticks_per_second
+	_is_owner = peer_id == multiplayer.get_unique_id()
+
+	# Only ever claim the camera for the local owner. Whichever Camera2D
+	# enters the SceneTree first auto-claims the viewport's active camera
+	# regardless of its own `current` value (Godot's built-in "first camera
+	# wins" fallback) — with MultiplayerSpawner catch-up replication, that's
+	# often another peer's ship (e.g. the always-present server-ghost ship
+	# for peer 1), not ours. Setting `current = true` via property/deferred
+	# assignment does not reliably dethrone that auto-claimed camera; calling
+	# make_current() does, since it's the actual API that updates the
+	# viewport's tracked active camera rather than just the local property.
+	if _is_owner:
+		var camera := get_node_or_null("Camera2D") as Camera2D
+		if camera:
+			camera.call_deferred("make_current")
+
+	PlayerRegistry.loadout_updated.connect(_on_loadout_updated)
+	var info := PlayerRegistry.get_info(peer_id)
+	if info.is_empty():
 		visible = false
 		set_physics_process(false)
-		GameConfig.team_selected.connect(_on_team_selected)
 	else:
-		_init_player()
+		_init_player(info)
 
 
-func _on_team_selected() -> void:
-	_init_player()
+func _on_loadout_updated(updated_peer_id: int) -> void:
+	if updated_peer_id == peer_id:
+		_init_player(PlayerRegistry.get_info(peer_id))
 
 
-func _init_player() -> void:
+func _init_player(info: Dictionary) -> void:
 	var sprite := get_node_or_null("Sprite2D")
-	if sprite and not GameConfig.player_ship_path.is_empty():
-		sprite.texture = load(GameConfig.player_ship_path)
-		sprite.scale = Vector2.ONE * GameConfig.player_ship_scale
+	var ship_path: String = info.get("ship_path", "")
+	if sprite and not ship_path.is_empty():
+		sprite.texture = load(ship_path)
+		sprite.scale = Vector2.ONE * info.get("ship_scale", 1.0)
+	_ship_speed_factor = info.get("ship_speed_factor", 1.0)
 	set_physics_process(true)
-	_respawn()
+	if multiplayer.is_server():
+		_server_respawn()
+
 
 func _physics_process(delta: float) -> void:
 	if _dead:
 		return
 
-	# 1. INVINCIBILITY BLINK
+	# INVINCIBILITY BLINK — purely visual, runs once per real tick regardless
+	# of role (never part of prediction replay).
 	if _invincible:
 		_invincible_timer -= delta
 		modulate.a = 0.3 if int(_invincible_timer * 8) % 2 == 0 else 1.0
@@ -41,37 +91,142 @@ func _physics_process(delta: float) -> void:
 			_invincible = false
 			modulate.a = 1.0
 
-	# 2. ROTATION
-	if Input.is_action_pressed("move_right"):
+	if multiplayer.is_server():
+		_server_tick(delta)
+	elif _is_owner:
+		_owner_tick(delta)
+	else:
+		_remote_tick(delta)
+
+
+# ── Owner client: predict locally, send input to server ─────────────────────
+
+func _owner_tick(delta: float) -> void:
+	var input := _sample_local_input()
+	_input_tick += 1
+	_simulate_step(delta, input, true)
+
+	_pending_inputs.append({"tick": _input_tick, "input": input})
+	if _pending_inputs.size() > MAX_PENDING_INPUTS:
+		_pending_inputs.pop_front()
+	submit_input.rpc_id(1, _input_tick, input)
+
+
+@rpc("authority", "call_remote", "unreliable")
+func _receive_state(tick: int, pos: Vector2, rot: float, vel: Vector2, hp: int, shown: bool) -> void:
+	# Piggyback current health AND visibility on every state broadcast (not
+	# just the one-shot _apply_health/_apply_death/_apply_respawn RPCs) so a
+	# peer that connects after another ship already spawned/respawned still
+	# converges within a tick, instead of being stuck with that ship's
+	# defaults (health=0, invisible) forever — those one-shot RPCs only ever
+	# reach peers that were already connected at the moment they fired.
+	if health != hp:
+		health = hp
+		_update_hud()
+	visible = shown
+
+	if _is_owner:
+		_reconcile(tick, pos, rot, vel)
+	else:
+		_interp_from_pos = global_position
+		_interp_from_rot = rotation
+		_interp_to_pos = pos
+		_interp_to_rot = rot
+		_interp_elapsed = 0.0
+		velocity = vel
+
+
+func _reconcile(server_tick: int, server_pos: Vector2, server_rot: float, server_vel: Vector2) -> void:
+	var replay_index := -1
+	for i in _pending_inputs.size():
+		if _pending_inputs[i].tick == server_tick:
+			replay_index = i
+			break
+
+	global_position = server_pos
+	rotation = server_rot
+	velocity = server_vel
+
+	if replay_index == -1:
+		_pending_inputs.clear()
+		return
+
+	_pending_inputs = _pending_inputs.slice(replay_index + 1)
+	for entry in _pending_inputs:
+		_simulate_step(_fixed_delta, entry.input, false)
+
+
+# ── Server: simulate every ship, broadcast authoritative state ──────────────
+
+func _server_tick(delta: float) -> void:
+	var input: Dictionary
+	if _is_owner:
+		input = _sample_local_input()
+	else:
+		if not _remote_inputs.is_empty():
+			var entry: Dictionary = _remote_inputs.pop_front()
+			_last_remote_input = entry.input
+			_last_processed_tick = entry.tick
+		input = _last_remote_input
+
+	_simulate_step(delta, input, true)
+	_server_process_shoot(delta, input)
+
+	_receive_state.rpc(_last_processed_tick, global_position, rotation, velocity, health, visible)
+
+
+@rpc("any_peer", "call_remote", "unreliable")
+func submit_input(tick: int, input: Dictionary) -> void:
+	if not multiplayer.is_server():
+		return
+	if multiplayer.get_remote_sender_id() != peer_id:
+		return
+	_remote_inputs.append({"tick": tick, "input": input})
+	if _remote_inputs.size() > MAX_PENDING_INPUTS:
+		_remote_inputs.pop_front()
+
+
+# ── Remote client: no local simulation, just interpolate toward last snapshot ─
+
+func _remote_tick(delta: float) -> void:
+	_interp_elapsed += delta
+	var t: float = clamp(_interp_elapsed / _fixed_delta, 0.0, 1.0)
+	global_position = _interp_from_pos.lerp(_interp_to_pos, t)
+	rotation = lerp_angle(_interp_from_rot, _interp_to_rot, t)
+
+
+# ── Shared movement step (deterministic — replayed during reconciliation) ───
+
+func _sample_local_input() -> Dictionary:
+	return {
+		"up": Input.is_action_pressed("move_up"),
+		"down": Input.is_action_pressed("move_down"),
+		"left": Input.is_action_pressed("move_left"),
+		"right": Input.is_action_pressed("move_right"),
+		"shoot": Input.is_action_pressed("shoot"),
+	}
+
+
+# apply_side_effects gates anything non-deterministic-safe (e.g. dealing
+# damage) so replaying buffered inputs during reconciliation can't double it.
+func _simulate_step(delta: float, input: Dictionary, apply_side_effects: bool) -> void:
+	if input.get("right", false):
 		rotation += GameConfig.ship_rotation_speed * delta
-	if Input.is_action_pressed("move_left"):
+	if input.get("left", false):
 		rotation -= GameConfig.ship_rotation_speed * delta
 
-	# 3. THRUST
-	var thrust := GameConfig.ship_thrust * GameConfig.player_ship_speed_factor
-	var max_speed := GameConfig.ship_max_speed * GameConfig.player_ship_speed_factor
-	if Input.is_action_pressed("move_up"):
+	var thrust := GameConfig.ship_thrust * _ship_speed_factor
+	var max_speed := GameConfig.ship_max_speed * _ship_speed_factor
+	if input.get("up", false):
 		velocity += Vector2.UP.rotated(rotation) * thrust * delta
-	if Input.is_action_pressed("move_down"):
+	if input.get("down", false):
 		velocity += Vector2.DOWN.rotated(rotation) * thrust * delta
-
 	velocity = velocity.limit_length(max_speed)
 
 	var velocity_before_move := velocity
 	move_and_slide()
-	_handle_environment_collisions(velocity_before_move)
+	_apply_collision_bounce(velocity_before_move, apply_side_effects)
 
-	# 4. SHOOT
-	_fire_cooldown -= delta
-	if Input.is_action_pressed("shoot") and _fire_cooldown <= 0.0:
-		_fire_cooldown = GameConfig.ship_fire_rate
-		var bullet = BULLET_SCENE.instantiate()
-		bullet.global_position = global_position + Vector2.UP.rotated(rotation) * 40.0
-		bullet.velocity = Vector2.UP.rotated(rotation) * GameConfig.bullet_speed + velocity
-		bullet.source = self
-		get_parent().add_child(bullet)
-
-	# 5. WALL COLLISION
 	var bounds = GameConfig.world_bounds
 	if global_position.x < bounds.position.x or global_position.x > bounds.end.x:
 		velocity.x = 0
@@ -80,7 +235,8 @@ func _physics_process(delta: float) -> void:
 		velocity.y = 0
 		global_position.y = clamp(global_position.y, bounds.position.y, bounds.end.y)
 
-func _handle_environment_collisions(previous_velocity: Vector2) -> void:
+
+func _apply_collision_bounce(previous_velocity: Vector2, apply_side_effects: bool) -> void:
 	for i in get_slide_collision_count():
 		var collision := get_slide_collision(i)
 		var collider := collision.get_collider() as Node
@@ -95,29 +251,69 @@ func _handle_environment_collisions(previous_velocity: Vector2) -> void:
 		if impact_speed <= 0.0:
 			continue
 		velocity = previous_velocity.bounce(normal) * GameConfig.ship_bounce_restitution
-		if is_hazard:
+		if is_hazard and apply_side_effects and multiplayer.is_server():
 			var damage := int(impact_speed * GameConfig.ship_collision_damage_scale)
 			if damage > 0:
 				take_damage(damage)
 
 
+# Server-only: decides whether this tick's queued input fires a shot, using
+# its own authoritative cooldown (never trust a client's fire rate). Requests
+# World spawn the bullet, which replicates it to every peer.
+func _server_process_shoot(delta: float, input: Dictionary) -> void:
+	_fire_cooldown -= delta
+	if input.get("shoot", false) and _fire_cooldown <= 0.0:
+		_fire_cooldown = GameConfig.ship_fire_rate
+		var world := get_node_or_null("/root/World")
+		if world:
+			world.request_bullet_spawn(
+				peer_id,
+				global_position + Vector2.UP.rotated(rotation) * 40.0,
+				Vector2.UP.rotated(rotation) * GameConfig.bullet_speed + velocity
+			)
+
+
+# ── Health / death — server-authoritative, broadcast to every peer ──────────
+
 func take_damage(amount: int) -> void:
+	if not multiplayer.is_server():
+		return
 	if _invincible or _dead:
 		return
 	health = max(0, health - amount)
-	_update_hud()
+	_apply_health.rpc(health)
 	if health == 0:
 		_die()
 
+
+@rpc("authority", "call_remote", "reliable")
+func _apply_health(new_health: int) -> void:
+	health = new_health
+	_update_hud()
+
+
 func _die() -> void:
+	if not multiplayer.is_server():
+		return
+	_apply_death.rpc()
+	await get_tree().create_timer(GameConfig.ship_respawn_delay).timeout
+	_server_respawn()
+
+
+@rpc("authority", "call_local", "reliable")
+func _apply_death() -> void:
 	_dead = true
 	visible = false
 	velocity = Vector2.ZERO
-	await get_tree().create_timer(GameConfig.ship_respawn_delay).timeout
-	_respawn()
 
-func _respawn() -> void:
-	global_position = _get_spawn_position()
+
+func _server_respawn() -> void:
+	_apply_respawn.rpc(_get_spawn_position())
+
+
+@rpc("authority", "call_local", "reliable")
+func _apply_respawn(pos: Vector2) -> void:
+	global_position = pos
 	velocity = Vector2.ZERO
 	rotation = 0.0
 	health = GameConfig.ship_max_health
@@ -125,6 +321,15 @@ func _respawn() -> void:
 	visible = true
 	_invincible = true
 	_invincible_timer = GameConfig.ship_invincibility_time
+
+	_interp_from_pos = global_position
+	_interp_to_pos = global_position
+	_interp_from_rot = rotation
+	_interp_to_rot = rotation
+	_interp_elapsed = 0.0
+	_pending_inputs.clear()
+	_remote_inputs.clear()
+
 	_update_hud()
 
 func _get_spawn_position() -> Vector2:
@@ -135,6 +340,8 @@ func _get_spawn_position() -> Vector2:
 
 
 func _update_hud() -> void:
+	if not _is_owner:
+		return
 	var label = get_node_or_null("/root/World/HUD/HealthLabel")
 	if label:
 		label.text = "HP: %d / %d" % [health, GameConfig.ship_max_health]

spacewar/world/world.gd

@@ -1,8 +1,20 @@
 extends Node2D
 
 const MAP_SCENE: PackedScene = preload("res://world/maps/map_01.tscn")
+const SHIP_SCENE: PackedScene = preload("res://ships/ship.tscn")
+const BULLET_SCENE: PackedScene = preload("res://ships/bullet.tscn")
 
 @onready var _map_container: Node2D = $MapContainer
+@onready var _players: Node2D = $Players
+@onready var _spawner: MultiplayerSpawner = $MultiplayerSpawner
+@onready var _bullets: Node2D = $Bullets
+@onready var _bullet_spawner: MultiplayerSpawner = $BulletSpawner
+@onready var _team_select: TeamSelect = $TeamSelect
+
+# Server-authoritative: the 2 races offered for this match, decided once and
+# shared by every player — see TeamSelect._ready(), which either reads this
+# directly (server's own instance) or requests it over RPC (remote clients).
+var _offered_race_ids: Array = []
 
 
 func _ready() -> void:
@@ -13,6 +25,82 @@ func _ready() -> void:
 		GameConfig.world_bounds = Rect2(background.position, background.size)
 	_build_tile_collisions(map)
 
+	_spawner.spawn_function = _spawn_ship
+	_bullet_spawner.spawn_function = _spawn_bullet
+	NetworkManager.peer_joined.connect(_on_peer_joined)
+	NetworkManager.peer_left.connect(_on_peer_left)
+
+	if multiplayer.is_server():
+		_spawn_peer(multiplayer.get_unique_id())
+		for peer_id in multiplayer.get_peers():
+			_spawn_peer(peer_id)
+
+
+# Picks the match's 2 offered races once and caches them, so every caller
+# (the server's own TeamSelect and every remote client's request) converges
+# on the same pair regardless of call order.
+func decide_offered_races() -> Array:
+	if _offered_race_ids.is_empty():
+		var ids := range(1, TeamSelect.RACES.size() + 1)
+		ids.shuffle()
+		_offered_race_ids = [ids[0], ids[1]]
+	return _offered_race_ids
+
+
+@rpc("any_peer", "call_remote", "reliable")
+func request_offered_races() -> void:
+	if not multiplayer.is_server():
+		return
+	var sender_id := multiplayer.get_remote_sender_id()
+	_deliver_offered_races.rpc_id(sender_id, decide_offered_races())
+
+
+@rpc("authority", "call_remote", "reliable")
+func _deliver_offered_races(race_ids: Array) -> void:
+	_team_select.offer_races(race_ids)
+
+
+func _spawn_peer(peer_id: int) -> void:
+	if _players.has_node(str(peer_id)):
+		return
+	_spawner.spawn(peer_id)
+
+
+func _spawn_ship(peer_id: int) -> Node:
+	var ship := SHIP_SCENE.instantiate()
+	ship.name = str(peer_id)
+	ship.peer_id = peer_id
+	return ship
+
+
+# Called by a Ship node running on the server when its authoritative fire
+# cooldown allows a shot. Replicated to every peer via the bullet spawner.
+func request_bullet_spawn(source_peer_id: int, pos: Vector2, vel: Vector2) -> void:
+	if not multiplayer.is_server():
+		return
+	_bullet_spawner.spawn({"peer_id": source_peer_id, "pos": pos, "vel": vel})
+
+
+func _spawn_bullet(data: Dictionary) -> Node:
+	var bullet := BULLET_SCENE.instantiate()
+	bullet.global_position = data.pos
+	bullet.velocity = data.vel
+	bullet.source_peer_id = data.peer_id
+	return bullet
+
+
+func _on_peer_joined(peer_id: int) -> void:
+	if multiplayer.is_server():
+		_spawn_peer(peer_id)
+
+
+func _on_peer_left(peer_id: int) -> void:
+	if not multiplayer.is_server():
+		return
+	var ship := _players.get_node_or_null(str(peer_id))
+	if ship:
+		ship.queue_free()
+
 
 # Tiles have no collision shapes of their own, so spawn one StaticBody2D per
 # occupied cell. Asteroids get round hitboxes to roughly match their sprites.

spacewar/world/world.tscn

@@ -1,6 +1,5 @@
 [gd_scene format=3 uid="uid://c77s15ns13p6y"]
 
-[ext_resource type="PackedScene" uid="uid://dygtdlkvo6ofl" path="res://ships/ship.tscn" id="1_f3sb7"]
 [ext_resource type="PackedScene" uid="uid://cpausemenu01a" path="res://menu/pause_menu.tscn" id="2_pm"]
 [ext_resource type="PackedScene" uid="uid://dteamselect01" path="res://menu/team_select.tscn" id="3_ts"]
 [ext_resource type="Script" path="res://world/world.gd" id="4_world"]
@@ -10,7 +9,15 @@ script = ExtResource("4_world")
 
 [node name="MapContainer" type="Node2D" parent="."]
 
-[node name="Player" parent="." unique_id=2118863138 instance=ExtResource("1_f3sb7")]
+[node name="Players" type="Node2D" parent="."]
+
+[node name="MultiplayerSpawner" type="MultiplayerSpawner" parent="."]
+spawn_path = NodePath("../Players")
+
+[node name="Bullets" type="Node2D" parent="."]
+
+[node name="BulletSpawner" type="MultiplayerSpawner" parent="."]
+spawn_path = NodePath("../Bullets")
 
 [node name="HUD" type="CanvasLayer" parent="."]