Horizon Simple Market Maker

The simplest possible Horizon strategy: fixed fair value with a fixed spread.

The simplest possible strategy. Quotes a fixed fair value with a fixed spread on paper.

Full Code

"""Minimal 20-line Horizon example."""

import horizon as hz


def fair_value(ctx: hz.Context) -> float:
    """Simple fair value: just return 0.5 (coin flip)."""
    return 0.50


def quoter(ctx: hz.Context, fair: float) -> list[hz.Quote]:
    """Quote around the fair value with a fixed spread."""
    return hz.quotes(fair, spread=0.06, size=5)


hz.run(
    name="simple_mm",
    markets=["test-market"],
    pipeline=[fair_value, quoter],
    risk=hz.Risk(max_position=100, max_drawdown_pct=5),
    interval=1.0,
    mode="paper",
)

How It Works

1. fair_value returns a constant 0.50, a 50/50 coin flip market
2. quoter receives the fair value and creates quotes:

• Bid: 0.50 - 0.03 = 0.47
• Ask: 0.50 + 0.03 = 0.53
• Size: 5 contracts

3. Each cycle, the paper exchange matches orders against the mid price
4. When fills occur, positions are tracked and P&L is calculated

Run It

python examples/simple.py

# Or with dashboard
python -m horizon run examples/simple.py --dashboard

Extending

Add inventory skew to lean quotes away from your position:

def quoter(ctx: hz.Context, fair: float) -> list[hz.Quote]:
    skew = ctx.inventory.net * 0.001
    return hz.quotes(fair - skew, spread=0.06, size=5)

Add a feed for dynamic fair value:

from horizon.context import FeedData

def fair_value(ctx: hz.Context) -> float:
    btc = ctx.feeds.get("btc", FeedData())
    return btc.price * 0.01 if btc.price > 0 else 0.50

hz.run(
    feeds={"btc": hz.BinanceWS("btcusdt")},
    ...
)