160 lines
6.5 KiB
Markdown
160 lines
6.5 KiB
Markdown
# Polymarket Arbitrage Scanner
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A production-grade Python asyncio scanner that detects **NegRisk multi-outcome
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arbitrage** on Polymarket, simulates fills in paper mode with realistic
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latency penalties, and can sign + submit live orders through `py-clob-client`
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behind hard risk gates.
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**[Live browser demo](https://matthewnyc2.github.io/arbitrage/demo.html)** ·
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**[Project overview](https://matthewnyc2.github.io/arbitrage/)** ·
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**[Architecture](DESIGN.md)**
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---
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## The arbitrage
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Polymarket hosts *categorical* events (e.g. "Who wins the 2028 Election?")
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where every outcome trades as its own YES token. Because exactly one outcome
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must win, the fair prices across all outcomes must sum to $1. When the
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*sum of best-asks* across every outcome drops below $1, buying a complete
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set is a guaranteed $1 payout — a risk-free arbitrage.
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```
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Σ best_ask(outcome_i) < $1.00 ⟹ buy one of each, redeem for $1
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```
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The scanner watches the live CLOB, walks the order book depth to size each
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leg honestly, subtracts fees and amortised Polygon gas, and emits sized
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opportunities in real time.
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## Quickstart
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```bash
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git clone https://github.com/matthewnyc2/arbitrage
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cd arbitrage
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python -m venv .venv && source .venv/bin/activate # Windows: .venv\Scripts\activate
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pip install -e ".[dev]"
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cp .env.example .env
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arb init # create SQLite schema
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arb discover # pull active negRisk events from Polymarket
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arb scan & # start the paper scanner (WS + engine + executor)
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arb web # dashboard at http://127.0.0.1:8000
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```
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### Or with Docker
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```bash
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docker compose up
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# dashboard at http://127.0.0.1:8000
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```
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## What you're looking at
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| Piece | File | Purpose |
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|---|---|---|
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| Gamma REST discovery | `arbitrage/clients/polymarket_rest.py` | Paginates `/events`, filters to active negRisk categoricals, upserts to SQLite |
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| WebSocket L2 book maintainer | `arbitrage/clients/polymarket_ws.py` + `arbitrage/book/l2.py` | Subscribes to CLOB market channel, parses `book` / `price_change` events, maintains per-token sorted ladders with desync detection |
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| Opportunity engine | `arbitrage/engine/opportunity.py` | On every book tick, walks depth on every outcome, computes VWAP basket cost, picks the size that maximizes net expected profit after fees + gas |
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| Paper executor | `arbitrage/engine/paper_fills.py` | Simulates IOC fills at `detection + latency_ms` against the live book, writes baskets + fills to SQLite, marks PnL on resolution |
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| Live executor | `arbitrage/engine/live_executor.py` | Signs EIP-712 orders via `py-clob-client`, submits FAK in parallel across legs, unwinds partial fills, redeems on resolution. Gated behind `ARB_MODE=live` + risk caps |
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| Risk gate | `arbitrage/engine/live_executor.py::risk_gate` | Hard caps: basket USD, open-basket count (global + per-event), daily loss stop, kill-switch file |
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| Dashboard | `arbitrage/web/app.py` + `templates/` | FastAPI + HTMX single page, auto-refreshing tables, one-click kill switch |
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| CLI | `arbitrage/cli.py` | `arb init \| discover \| scan \| web \| resolve` |
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## Architecture
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```
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Gamma REST CLOB WebSocket
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│ │
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▼ ▼
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Event discovery L2 Book Maintainer
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(active negRisk) (per token, in-memory)
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│ │
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└────────────┬───────────────┘
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▼
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Opportunity Engine
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(depth-walk, fee-net, gas-amortized threshold)
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│
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▼
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Risk Gate
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(basket caps, daily loss, kill switch)
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│
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┌────────────┴───────────────┐
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▼ ▼
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Paper Executor Live Executor
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(latency-penalized (sign + FAK + redeem)
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sim fills + PnL) │
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│ │
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└────────────┬───────────────┘
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▼
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SQLite (WAL)
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│
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▼
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FastAPI + HTMX dashboard
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```
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## Modes
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- **`ARB_MODE=paper`** (default) — real data, simulated fills, no keys touched.
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Paper baskets sit `pending_resolution` until the underlying market closes,
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then flip to `redeemed` or `invalid` and realized PnL is booked.
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- **`ARB_MODE=live`** — signs and submits real orders, redeems complete sets
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via `NegRiskAdapter.redeemPositions`. `LiveExecutor.dry_run=True` by default
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so orders are logged rather than broadcast until an operator explicitly
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flips the flag.
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## Safety rails
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| Cap | Env var | Default |
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| Minimum net edge (bps) | `ARB_MIN_NET_EDGE_BPS` | 50 |
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| Max USD per basket | `ARB_MAX_BASKET_USD` | 50 |
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| Max open baskets (global) | `ARB_MAX_OPEN_BASKETS` | 3 |
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| Max open baskets per event | hardcoded | 1 |
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| Daily loss stop (USD) | `ARB_DAILY_LOSS_STOP_USD` | 100 |
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| Kill switch file | `ARB_KILL_SWITCH_FILE` | `./KILL` |
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| Paper-mode latency penalty (ms) | `ARB_PAPER_LATENCY_MS` | 250 |
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The dashboard has a red **kill** button that touches the kill-switch file;
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the executor refuses to open any new baskets while that file exists.
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## Test suite
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```bash
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pytest # 60 tests, ~5s
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pytest --cov=arbitrage # with coverage
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```
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Coverage on the core math layers:
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| Module | Coverage |
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|---|---:|
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| `arbitrage/book/l2.py` | 94% |
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| `arbitrage/engine/paper_fills.py` | 94% |
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| `arbitrage/web/app.py` | 92% |
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| `arbitrage/db.py` | 100% |
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| `arbitrage/engine/opportunity.py` | 81% |
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## Tech stack
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Python 3.12 · asyncio · pydantic v2 · FastAPI + HTMX + Jinja2 · SQLite (WAL) ·
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`py-clob-client` · `web3.py` · `httpx` · `websockets` · `tenacity` · `loguru` ·
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pytest + pytest-asyncio · Docker
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## Status
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Phase 1 (paper-workable) is complete — scanner runs end-to-end, all 60 tests
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pass, CI green. Live executor skeleton is in place but gated. See
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[`STATUS.html`](STATUS.html) for an honest plain-English breakdown of what
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works, what doesn't, and what it would take to run this in anger.
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## License
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MIT. See `LICENSE`.
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