Bot for Polymarket
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Order book basics for Polymarket bots
A bot that only knows “buy YES at 0.52” does not know the book. Edge lives in depth, queue, and fee drag — not in a single mid price.
What the book is telling you
- Top of book — best bid/ask; thin tops lie about depth
- Depth a few ticks away — where your size actually fills
- Spread — the tax you pay for urgency
- Stale books — disconnects and lag look like free money until they do not
Maker vs taker (after July 2026 US Θ)
When taker Θ rises, limit designs matter more. That does not mean “always make.” It means your model must price the cost of taking at mid — see July 2026 fees.
| Style | Pays for | Risk |
|---|---|---|
| Taker | Speed / certainty of fill | Fee drag + adverse selection |
| Maker / limit | Better fee economics (when schedule favors it) | Queue, non-fill, adverse selection |
Bot design implications
- Never size from top-of-book alone — walk the book in the model
- Kill on stale data — a frozen book is not an opportunity
- Paper with realistic fills — risk controls
- Confirm path before you trust any book tutorial — US vs International
This page is part of the Polymarket trading bots handbook.
Join the Bot for Polymarket waitlist if you want a hosted path with risk limits.
Market Mechanics Desk · Updated 2026-07-08