The Codebase

Is this real?
Yes it does.

Fee → server roll → stored ticket → winner launches → Match Engine buys. That architecture runs on useslot.fun today. Reels on the client only animate the server result.

pump.fun

Spin for real How It Works

FAQ

Is this real?

Yes it does.

Conceptually and in production: a paid SOL fee is verified on-chain, the server rolls published odds, the ticket is persisted, losses fund the treasury, and wins build a Pump.fun create with Slot matching an equal SOL purchase after launch confirms. The Match Engine’s private signer stays sealed — the public path above is what you can audit here.

✓Server-authoritative RNG (randomInt, no modulo bias)
✓Payment signature consumed once (replay lock)
✓Fee payer must sign; treasury must receive ≥ fee
✓Match size capped in lamports at ticket time (≤ 1 SOL)
✓Match runs once per ticket (status → MATCHED)
✓Demo reels ≠ live odds (show ~1/3 · live ~10%)

Win rate

…

Spin fee

…

to Slot treasury

Match engine

…

equal SOL after confirm

Max match

1 SOL

server-enforced ceiling

1) Published odds

Live jackpot = WIN_RATE_BPS / 10_000. Default 1000 → exactly 10%. Uses crypto.randomInt so the selection is uniform.

Uniform roll

src/services/spin.ts → rollSpinOutcome

// src/services/spin.ts — uniform jackpot odds
import { randomInt } from "node:crypto";

export function rollSpinOutcome() {
  const n = randomInt(10_000);          // [0, 10000)
  const win = n < winRateBps();         // 1000 bps = exactly 10%

  if (win) {
    return { win: true, reels: ["🚀", "🚀", "🚀"] as const };
  }

  let reels: [string, string, string];
  do {
    reels = [
      SYMBOLS[randomInt(SYMBOLS.length)]!,
      SYMBOLS[randomInt(SYMBOLS.length)]!,
      SYMBOLS[randomInt(SYMBOLS.length)]!,
    ];
  } while (reels.every((s) => s === "🚀"));

  return { win: false, reels };
}

2) Fee → ticket

Payment signature is claimed once, then verified on-chain. Opening buy is clamped to lamports and stored on the ticket before any match can run.

Play route

src/app/api/spin/play/route.ts

// POST /api/spin/play — fee → roll → immutable ticket
const spinId = newSpinId();
const openingBuyLamports = clampOpeningBuyLamports(body.openingBuySol); // ≤ 1 SOL

const claimed = await markPaymentUsed(paymentSignature); // replay lock
if (!claimed) throw new Error("payment already used");

await verifyFeePayment({
  signature: paymentSignature,
  fromWallet: wallet,          // must be a signer
  feeWallet: quote.feeWallet,  // treasury destination
  minLamports: launchFeeLamports(),
});

const { win, reels } = rollSpinOutcome();

await saveTicket({
  id: spinId,
  wallet,
  paymentSignature,
  win,
  reels,
  openingBuyLamports,
  maxMatchLamports: openingBuyLamports,
  status: win ? "PAID_WIN" : "PAID_LOSS",
  ...
});

return { spinId, win, reels };

Payment checks

src/services/spin.ts → verifyFeePayment

// Fee verification checklist (server)
✓ tx found + meta.err === null (confirmed)
✓ fromWallet is a required signer
✓ feeWallet balance increased ≥ launchFeeLamports
✓ payer funded the transfer (sent ≥ fee)
✓ SystemProgram transfer when decodable
✓ payment age ≤ 30 minutes
✓ paymentSignature unique (KV spinpay:{sig} once)

3) Launch + equal SOL match

Slot matches your opening buy with an equal SOL purchase after launch confirms. The second buy hits a later point on the curve — we never claim “double the tokens.” Match is one-shot per ticket.

pump.fun

Match Engine · sealed · online

Match (public surface)

MatchEngine · replay-safe

// Match Engine — equal SOL after create confirms (sealed)
// Spends ticket.maxMatchLamports only — never client “100 SOL” claims.

if (ticket.matchSignature || ticket.status === "MATCHED") {
  throw new Error("already matched"); // replay lock
}

await assertCreateConfirmed(createSignature);
assertMintMatchesTicket(mint, ticket.mint);

const lamportsIn = min(ticket.maxMatchLamports, MAX_OPENING_BUY_LAMPORTS);

const result = await MatchEngine.execute({
  mint,
  lamportsIn,                 // equal SOL purchase
  venue: "pump.fun",
});

ticket.status = "MATCHED";
ticket.matchSignature = result.signature;
await saveTicket(ticket);

// Wording: Slot matches your opening buy with an equal SOL purchase
// after your launch confirms — not “double the tokens on the curve.”

Yes it does — spin when you’re ready.

Live launchpad: 10% after the 0.05 SOL treasury fee. Demo on Home is show-only.

Open Launch Risk disclosure