Funded Crossword

March 20, 2026 · View on GitHub

Real-time multiplayer crossword-style game with:

  • Node.js + Express backend (backend/)
  • PostgreSQL persistence
  • SSE realtime updates
  • React + Vite frontend (frontend/)

Tempo Mainnet: Defaults target Tempo Mainnet (chain 4217): MPP_TESTNET=false, TEMPO_RPC_URL=https://rpc.presto.tempo.xyz. The frontend uses viem’s tempo chain with the same RPC.

Tempo Moderato testnet (matches mppx testnet: true, chain 42431): set MPP_TESTNET=true, TEMPO_RPC_URL=https://rpc.moderato.tempo.xyz, and in frontend/src/wagmiConfig.ts use tempoModerato instead of tempo.

On-chain checks (TIP-20)

Payments use TEMPO_CURRENCY; winner payouts use the same token from WINNER_PAYOUT_PRIVATE_KEY. Verify RPC chain id and balances:

cd backend
npm run tempo:check

Project Structure

  • backend/ - API server, game logic, DB schema/init
  • frontend/ - web app UI (mobile-first responsive)

Prerequisites

  • Node.js 18+ (recommended)
  • PostgreSQL running locally or remotely

Backend Setup

  1. Copy env template and fill values:
cd backend
cp .env.example .env
  1. Set at least:
  • DATABASE_URL
  1. Install and run:
npm install
npm run dev

Backend default URL: http://localhost:3001

Health check:

GET /healthz

Frontend Setup

  1. Install and run:
cd frontend
npm install
npm run dev

Frontend default URL: http://localhost:5173

If needed, set API base URL in frontend env:

VITE_API_BASE=http://localhost:3001

Core API Endpoints

  • GET /puzzles - list puzzles (?status=all|active|completed)
  • POST /puzzles/create - create puzzle
  • GET /puzzles/:id - fetch one puzzle
  • POST /puzzles/:id/reveal - reveal a random unrevealed letter
  • POST /puzzles/:id/guess - guess full answer or char+index
  • GET /events/puzzles/:id - SSE realtime stream

Demo User Identity

For mutating actions, backend uses:

  • x-user-address header (preferred), or
  • user_address in request body, or
  • fallback: demo-user

Frontend includes a user-id input to simulate multiplayer users.

Notes

  • Inputs are normalized/validated to uppercase alphanumeric (with spaces where allowed).
  • Completed puzzles display full answer for all users.
  • Char guesses on already revealed positions are rejected.