17-0 Showdown Online Browser Game

What is it?

17-0 Showdown is a full-stack NFL fantasy draft game built entirely in the browser. You assemble a squad of 22 historical players — spanning every era from the 1970s through the 2020s — and simulate a complete 17-game NFL regular season. The simulation engine runs client-side using a seeded deterministic LCG (linear congruential generator), meaning every result is reproducible given the same seed. Player OVR ratings are derived from real historical stats: QB completion %, yards per attempt, and sack rate; RB yards per carry and breakaway run %; WR catch rate and yards per route run; DB coverage grade and sack total. Over 70,000 players have logged games since launch.

Why I built it

I wanted to build a polished, multiplayer-capable game could be built without a game engine — just React, a Postgres database, and a CDN. The popular 82-0 based around the NBA came out recently and I wanted to hop on the trend and create an NFL version. I also wanted to outperform big companies like Sleeper by having a larger player base and more features for the user to enjoy!

Key Features

Under the Hood

The actual architecture decisions — not marketing copy.

// Seeded LCG — same seed always produces the same game
function seededRng(seed) {
  let s = seed;
  return () => {
    s = (s * 1664525 + 1013904223) & 0xffffffff;
    return (s >>> 0) / 0xffffffff;
  };
}

function simulateGame(homeTeam, awayTeam, seed) {
  const rng = seededRng(seed);
  // Each play call advances the RNG deterministically.
  // Both clients run identical logic — no server-side
  // simulation needed, no result sync over the wire.
}

-- PostgreSQL advisory lock prevents race conditions.
-- Multiple clients search for open matches concurrently;
-- the first to acquire the lock claims it, others skip.
SELECT * FROM online_matches
WHERE status = 'waiting'
  AND mode = p_mode
FOR UPDATE SKIP LOCKED
LIMIT 1;

Tech Stack