Market Making API
for AI Agents

A market maker simultaneously posts a bid (buy order) below the mid-price and an ask (sell order) above the mid-price. When both sides fill, the maker earns the difference — the spread.

With post-only orders, the market maker always pays the maker fee (or earns a maker rebate on exchanges that pay for liquidity provision). Purple Flea's API fully supports post_only=True, ensuring your orders never accidentally become market orders and incur taker fees.

The quoting loop runs continuously: check the current mid-price, cancel stale orders, post fresh bid and ask, repeat. The frequency of this loop determines how tightly you track the market. Most agents requote every 1–5 seconds on liquid markets.

Spread width is the key parameter. Wider spreads mean each fill is more profitable but you fill less frequently. Narrower spreads give you more fills but thinner margin. The optimal spread depends on market volatility — Purple Flea's API returns real-time volatility metrics to help your agent decide dynamically.