FatherSon

Posted on Jul 15

Forking stack-x0: Building a Simple Directional Crypto Up/Down Bot on Polymarket

One of the more consistent performers on Polymarket’s short-duration crypto markets is @stack-x0.

Its strategy is remarkably straightforward and durable:

For each active crypto Up/Down slot (BTC, ETH, SOL, XRP — 5m or 15m windows):

Determine direction from CEX lead vs slot open (spot price gap)
Identify the favorite side (currently priced ~52–57¢)
If favorite ask ∈ [0.50, 0.70] and conviction is OK → Taker buy $15–$60 (~50–100 shares)
Hold to resolution — redeem at $1 (win) or $0 (loss)
Never sell into the book. Never hedge the opposite side.

This is not high-frequency convergence sniping or lottery ticket farming. It’s a clean, mid-slot directional bet on the favorite when the edge is clear.

Here’s how to understand and fork this strategy.

Why This Approach Works

Focuses on mid-conviction ranges where the market has priced in a leader but hasn’t fully converged yet.
Avoids the razor-thin edges of late-game 94–99¢ sweeps (fee-sensitive).
Avoids deep lottery tickets (high variance).
Simple hold-to-redeem mechanic reduces execution complexity.
Leverages CEX lead as a real-time signal for slot direction.

The edge comes from consistently buying the favorite when it’s still reasonably priced (50–70¢) and letting resolution do the work.

Core Bot Architecture

1. Market Discovery

Scan for active crypto Up/Down slots:

// Example slot filter
const slots = await getActiveSlots();
for (const slot of slots) {
  if (!['btc', 'eth', 'sol', 'xrp'].includes(slot.asset)) continue;
  if (!['5m', '15m'].includes(slot.window)) continue;

  processSlot(slot);
}

2. Direction Signal (CEX Lead)

Compare current CEX spot price to the slot’s open price to infer likely winner.

3. Favorite Side Logic

Determine which side (YES/NO) is favored based on the lead.
Check current best ask on favorite side.

4. Entry Condition

if (
  favoriteAsk >= 0.50 && 
  favoriteAsk <= 0.70 && 
  convictionCheckOK(favoriteSide, leadStrength)
) {
  const notional = getPositionSize(15, 60); // $15–$60 range
  await takerBuy(favoriteSide, notional);
}

5. Position Management

Track all open positions by conditionId
On slot resolution → auto-redeem winners
No active selling or hedging

Risk Management & Sizing

Per-trade notional: Keep small ($15–$60) to survive strings of losses
Concurrent exposure: Monitor total capital at risk across overlapping slots
Daily/weekly drawdown limits: Critical for survival
Fee awareness: Taker fees matter — calculate edge after fees

Data Feeds You’ll Need

Polymarket CLOB WebSocket (live prices)
CEX ticker (Binance/Coinbase for lead signal)
Gamma API or Polymarket Data API (slot metadata, conditionIds)
On-chain oracle for resolution confirmation

Potential Improvements When Forking

Add basic conviction filters (stronger CEX lead = larger size)
Implement simple position sizing based on volatility or time remaining
Add logging + performance tracking per slot type
Include circuit breakers if drawdown exceeds threshold
Cache market data aggressively for speed

Important Caveats

Past performance (even from successful wallets) is no guarantee of future results
Short-duration markets are competitive — execution speed and fee rebates matter
Regime changes (volatility spikes, fee adjustments) can hurt this style
Start small and paper trade before going live

The beauty of stack-x0’s approach is its simplicity. It doesn’t rely on complex models or constant optimization. It finds a repeatable edge and executes it consistently across thousands of markets.

Many sophisticated bots fail where simple, disciplined ones survive.

If you’re building your own Polymarket bot, this directional mid-slot style is a solid foundation to study and fork.

What part of the strategy are you planning to implement first?

If you have more questions, please feel free to contact me at any time: https://t.me/FatherSon97

#Polymarket #TradingBot #CryptoTrading #PredictionMarkets #AgenticTrading #Solana #DeFi #BotDevelopment

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