Polymarket Integration
All prediction market trades on Bullpen execute through Polymarket's hybrid-decentralized orderbook on Polygon.
What is Polymarket?
Polymarket is a prediction market protocol built on Polygon. It operates a hybrid-decentralized Central Limit Order Book (CLOB) where order matching happens off-chain while settlement and execution occur on-chain.
The system has three core components:
CLOB Operator: Handles order matching and book management off-chain
Exchange Contract: Executes matched trades on-chain via atomic swaps
Conditional Token Framework (CTF): Gnosis-based ERC1155 tokens representing market outcomes
Bullpen routes prediction market orders to Polymarket's CLOB.
How Orders Execute
You place an order through Bullpen
Order is signed with your wallet (EIP-712 structured data)
Submitted to Polymarket's CLOB operator
Operator matches your order against resting liquidity
Matched orders are submitted to the Exchange contract on Polygon
Trade settles on-chain, tokens transfer to your proxy wallet
Order matching is off-chain for speed. Settlement is on-chain for security and custody.
Order Book Mechanics
Polymarket uses price-time priority with a unified orderbook:
Best prices execute first
At the same price, oldest orders fill first
Yes and No orders match against each other on a single book
The unified book means a Yes buy at $0.60 can match against a No buy at $0.40. When their prices sum to $1.00, the operator creates new outcome tokens from collateral and distributes them.
Order Matching Types
Orders can match in three ways:
Fill
Your order matches against an existing resting order
Mint
Two opposing orders (Yes + No) summing to $1.00 create new tokens
Merge
Two sell orders (Yes + No) burn tokens and release collateral
Supported Order Types
Polymarket supports limit orders as the base primitive. Market orders are simulated by using marketable limit prices.
GTC
Good-Til-Cancelled. Rests on the book until filled or cancelled
FOK
Fill-Or-Kill. Must fill entirely and immediately, or cancel
GTD
Good-Til-Date. Expires at a specified timestamp
See Order Types for details on each.
Margin and Collateral
Prediction markets on Polymarket do not use leverage. All positions are fully collateralized.
When you place an order:
Your available USDC.e balance is checked
The order amount is reserved against your balance
You cannot place additional orders exceeding your remaining balance
Example: With 500 USDC.e, you can place one order to buy 1,000 Yes shares at $0.50. Any additional orders in that market will be rejected until the first order fills or is cancelled.
Price Display
Prices shown on Polymarket represent the midpoint of the bid-ask spread, unless the spread exceeds $0.10. In wide-spread markets, the last traded price is displayed instead.
The orderbook displays:
Bid: Highest price someone will pay
Ask: Lowest price someone will sell
Spread: Difference between bid and ask
Depth: Total volume at each price level
Fees
Polymarket charges a taker fee on certain markets. These fees fund Polymarket's Maker Rebates Program, which redistributes fees daily to market makers to incentivize deeper liquidity and tighter spreads.
Makers are never charged fees. Only takers pay fees. Geopolitical markets are fee-free.
There are no Polymarket fees to deposit, withdraw, or redeem USDC
Fee Formula
Where C = number of shares traded and p = price of the shares. The effective rate peaks at 50% probability and decreases symmetrically toward $0.00 and $1.00.
Fee Structure by Category
Crypto
0.072
0
20%
Sports
0.03
0
25%
Finance
0.04
0
25%
Politics
0.04
0
25%
Economics
0.05
0
25%
Culture
0.05
0
25%
Weather
0.05
0
25%
Other / General
0.05
0
25%
Mentions
0.04
0
25%
Tech
0.04
0
25%
Geopolitics
0
0
—
See Polymarket's Fees Documentation for the latest information.
Conditional Tokens
Outcome shares are ERC-1155 tokens built on the Gnosis Conditional Token Framework (CTF). Each market has:
A condition ID identifying the market
Two position IDs for Yes and No outcomes
Collateral backing the tokens (USDC.e)
Full details in Positions and Settlement.
Multi-Outcome Markets
Some markets have more than two outcomes (e.g., "Who will win the election?" with multiple candidates).
These use the NegRiskAdapter contract:
Each candidate gets their own Yes/No binary market
Exactly one candidate's Yes resolves to $1.00
All other candidates' Yes tokens resolve to $0.00
No tokens can be converted across markets for capital efficiency
Sports Markets
Sports markets have special rules:
All outstanding limit orders are automatically cancelled when the game begins
The orderbook is cleared at the official start time
Only positions held at game start remain active
Key Polymarket Resources
For deeper technical details:
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