# Polymarket Arbitrage Cn

> Polymarket 套利 | Polymarket Arbitrage. 预测市场套利机会 | Prediction market arbitrage opportunities. 自动发现价格差异 | Auto discover price differences. 触发词：Polymarket、预测市场、套利、arbitrage.

- Skill: `lord1egypt/polymarket-arbitrage-cn` (Agent Skill)
- Install (CLI): `npx skillmds@latest add lord1egypt/polymarket-arbitrage-cn`
- Raw SKILL.md: https://api.skillmd.com/api/skills/lord1egypt/polymarket-arbitrage-cn/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: Lord1Egypt (https://skillmd.com/u/lord1egypt)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/lord1egypt/polymarket-arbitrage-cn

---

# Polymarket Arbitrage

Find and execute arbitrage opportunities on Polymarket prediction markets.

## Quick Start

### 1. Paper Trading (Recommended First Step)

Run a single scan to see current opportunities:

```bash
cd skills/polymarket-arbitrage
pip install requests beautifulsoup4
python scripts/monitor.py --once --min-edge 3.0
```

View results in `polymarket_data/arbs.json`

### 2. Continuous Monitoring

Monitor every 5 minutes and alert on new opportunities:

```bash
python scripts/monitor.py --interval 300 --min-edge 3.0
```

Stop with `Ctrl+C`

### 3. Understanding Results

Each detected arbitrage includes:
- **net_profit_pct**: Edge after 2% fees
- **risk_score**: 0-100, lower is better
- **volume**: Market liquidity
- **action**: What to do (buy/sell all outcomes)

Good opportunities:
- Net profit: 3-5%+
- Risk score: <50
- Volume: $1M+
- Type: `math_arb_buy` (safer)

## Arbitrage Types Detected

### Math Arbitrage (Primary Focus)

**Type A: Buy All Outcomes** (prob sum < 100%)
- Safest type
- Guaranteed profit if executable
- Example: 48% + 45% = 93% → 7% edge, ~5% net after fees

**Type B: Sell All Outcomes** (prob sum > 100%)
- Riskier (requires liquidity)
- Need capital to collateralize
- Avoid until experienced

See `references/arbitrage_types.md` for detailed examples and strategies.

### Cross-Market Arbitrage

Same event priced differently across markets (not yet implemented - requires semantic matching).

### Orderbook Arbitrage

Requires real-time orderbook data (homepage shows midpoints, not executable prices).

## Scripts

### fetch_markets.py

Scrape Polymarket homepage for active markets.

```bash
python scripts/fetch_markets.py --output markets.json --min-volume 50000
```

Returns JSON with market probabilities, volumes, and metadata.

### detect_arbitrage.py

Analyze markets for arbitrage opportunities.

```bash
python scripts/detect_arbitrage.py markets.json --min-edge 3.0 --output arbs.json
```

Accounts for:
- 2% taker fees (per leg)
- Multi-outcome fee multiplication
- Risk scoring

### monitor.py

Continuous monitoring with alerting.

```bash
python scripts/monitor.py --interval 300 --min-edge 3.0 [--alert-webhook URL]
```

Features:
- Fetches markets every interval
- Detects arbitrage
- Alerts on NEW opportunities only (deduplicates)
- Saves state to `polymarket_data/`

## Workflow Phases

### Phase 1: Paper Trading (1-2 weeks)

**Goal:** Understand opportunity frequency and quality

1. Run monitor 2-3x per day
2. Log opportunities in spreadsheet
3. Check if they're still available when you look
4. Calculate what profit would have been

**Decision point:** If seeing 3-5 good opportunities per week, proceed to Phase 2.

### Phase 2: Micro Testing ($50-100 CAD)

**Goal:** Learn platform mechanics

1. Create Polymarket account
2. Deposit $50-100 in USDC
3. Manual trades only (no automation)
4. Max $5-10 per opportunity
5. Track every trade in spreadsheet

**Decision point:** If profitable after 20+ trades, proceed to Phase 3.

### Phase 3: Scale Up ($500 CAD)

**Goal:** Increase position sizes

1. Increase bankroll to $500
2. Max 5% per trade ($25)
3. Still manual execution
4. Implement strict risk management

### Phase 4: Automation (Future)

Requires:
- Wallet integration (private key management)
- Polymarket API or browser automation
- Execution logic
- Monitoring infrastructure

**Only consider after consistently profitable manual trading.**

See `references/getting_started.md` for detailed setup instructions.

## Risk Management

### Critical Rules

1. **Maximum position size:** 5% of bankroll per opportunity
2. **Minimum edge:** 3% net (after fees)
3. **Daily loss limit:** 10% of bankroll
4. **Focus on buy arbs:** Avoid sell-side until experienced

### Red Flags

- Edge >10% (likely stale data)
- Volume <$100k (liquidity risk)
- Probabilities recently updated (arb might close)
- Sell-side arbs (capital + liquidity requirements)

## Fee Structure

Polymarket charges:
- **Maker fee:** 0%
- **Taker fee:** 2%

**Conservative assumption:** 2% per leg (assume taker)

**Breakeven calculation:**
- 2-outcome market: 2% × 2 = 4% gross edge needed
- 3-outcome market: 2% × 3 = 6% gross edge needed
- N-outcome market: 2% × N gross edge needed

**Target:** 3-5% NET profit (after fees)

## Common Issues

### "High edge but disappeared"

Homepage probabilities are stale or represent midpoints, not executable prices. This is normal. Real arbs disappear in seconds.

### "Can't execute at displayed price"

Liquidity issue. Low-volume markets show misleading probabilities. Stick to $1M+ volume markets.

### "Edge is too small after fees"

Increase `--min-edge` threshold. Try 4-5% for more conservative filtering.

## Files and Data

All monitoring data stored in `./polymarket_data/`:
- `markets.json` - Latest market scan
- `arbs.json` - Detected opportunities
- `alert_state.json` - Deduplication state (which arbs already alerted)

## Advanced Topics

### Telegram Integration (Future)

Pass webhook URL to monitor script for alerts:

```bash
python scripts/monitor.py --alert-webhook "https://api.telegram.org/bot<token>/sendMessage?chat_id=<id>"
```

### Position Sizing

For a 2-outcome math arb with probabilities p₁ and p₂ where p₁ + p₂ < 100%:

**Optimal allocation:**
- Bet on outcome 1: (100% / p₁) / [(100%/p₁) + (100%/p₂)] of capital
- Bet on outcome 2: (100% / p₂) / [(100%/p₁) + (100%/p₂)] of capital

This ensures equal profit regardless of which outcome wins.

**Simplified rule:** For small edges, split capital evenly across outcomes.

### Execution Speed

Arbs disappear fast. If planning automation:
- Use websocket connections (not polling)
- Place limit orders simultaneously
- Have capital pre-deposited
- Monitor gas fees on Polygon

## Resources

- **Polymarket:** https://polymarket.com
- **Documentation:** https://docs.polymarket.com
- **API (if available):** Check Polymarket docs
- **Community:** Polymarket Discord

## Support

For skill issues:
- Check `references/arbitrage_types.md` for strategy details
- Check `references/getting_started.md` for setup help
- Review output files in `polymarket_data/`
- Ensure dependencies installed: `pip install requests beautifulsoup4`