Placing Orders#

This guide covers how to place orders on the Seesaw order book.

Order Types#

Seesaw supports three order types:

Type	Behavior	Best For
Limit	Match what's possible, rest goes on book	Most trading
Post-Only	Reject if would match immediately	Market making
Immediate-or-Cancel (IOC)	Match what's possible, cancel rest	Taking liquidity

Order Sides#

You can express four different trading intentions:

How Orders Work#

1. Canonical Conversion#

All orders are converted to a single canonical form for matching:

Conversion Rules:

Buy YES @ p becomes BID @ p
Sell YES @ p becomes ASK @ p
Buy NO @ q becomes ASK @ (10000 - q)
Sell NO @ q becomes BID @ (10000 - q)

2. Tick Rounding#

Prices are rounded to the nearest tick (default 100 bps = 1%):

Side	Rounding	Reason
Bids	Round DOWN	Conservative for buyer
Asks	Round UP	Conservative for seller

Example (tick size = 100 bps):

Order	Before	After
Buy YES @ 6050	6050	6000 (round down)
Sell YES @ 5950	5950	6000 (round up)

3. Matching#

Orders match using price-time priority:

Placing a Buy Order#

Requirements#

Requirement	Description
Market State	Must be in TRADING state
Price	1 to 9999 basis points
Quantity	Greater than 0
Collateral	Sufficient USDC in wallet

Collateral Calculation#

For a buy order:

code

Required Collateral = (price_bps × quantity) / 10000

Example: Buy 100 YES @ 6000 bps

code

Collateral = (6000 × 100) / 10000 = 60 USDC

Order Flow#

Placing a Sell Order#

Requirements#

Requirement	Description
Market State	Must be in TRADING state
Share Ownership	Must own the shares you're selling
Price	1 to 9999 basis points
Quantity	Less than or equal to available shares

No Naked Shorts#

You can only sell shares you own:

Order Flow#

Self-Trade Prevention#

Orders from the same user cannot match against each other. If your new order would match your existing order, it skips and matches the next best price.

Order Parameters#

Parameter	Type	Description
`side`	OrderSide	BuyYes, SellYes, BuyNo, SellNo
`price_bps`	u16	Price in basis points [1, 9999]
`quantity`	u64	Number of shares
`order_type`	OrderType	Limit, PostOnly, IOC

Fee Structure#

Fee	Rate	Recipient
Taker Fee	200 bps (2.0%)	Split below
→ Protocol	150 bps (1.5%)	Treasury
→ Creator	50 bps (0.5%)	Market creator
Maker Fee	0 bps (0%)	—

Taker: Order that matches immediately Maker: Order that rests on the book

Order Book Visualization#

code

Market: BTC/USD (15-min duration)
         BIDS                    ASKS
Price    Qty     Total  |  Price    Qty     Total
-------------------------------------
5500     1,000   1,000  |  5600     500     500    <- Spread: 100 bps
5400     2,500   3,500  |  5700     1,200   1,700
5300     800     4,300  |  5800     3,000   4,700
5200     1,500   5,800  |  5900     750     5,450

Best Bid: 5500 bps (55%)
Best Ask: 5600 bps (56%)
Mid: 5550 bps

Trade Execution Example#

Incoming Order: Buy YES @ 5700 bps, qty = 1,000

Step	Match Price	Quantity	Cost
1	5600 bps	500	28.00 USDC
2	5700 bps	500	28.50 USDC
Total	5650 avg	1,000	56.50 USDC

Common Errors#

Error	Cause	Solution
`E_TRADING_NOT_STARTED`	Market not in TRADING state	Wait for start snapshot
`E_TRADING_ENDED`	Market past end time	Cannot trade after t_end
`E_INSUFFICIENT_COLLATERAL`	Not enough USDC	Deposit more USDC
`E_INSUFFICIENT_SHARES`	Selling more than owned	Reduce quantity
`E_WOULD_CROSS`	PostOnly order would match	Use Limit type
`E_ORDERBOOK_FULL`	64 orders per side limit	Wait for orders to fill

Best Practices#

Check the Spread: Wide spreads mean higher costs
Use Limit Orders: More control than market orders
Monitor Time: Orders are cancelled at market end
Calculate P&L: Know your breakeven price
Size Appropriately: Don't over-concentrate

Next Steps#

Learn Managing Positions
Understand Claiming Winnings

Placing Orders#

This guide covers how to place orders on the Seesaw order book.

Order Types#

Seesaw supports three order types:

Type	Behavior	Best For
Limit	Match what's possible, rest goes on book	Most trading
Post-Only	Reject if would match immediately	Market making
Immediate-or-Cancel (IOC)	Match what's possible, cancel rest	Taking liquidity

Order Sides#

You can express four different trading intentions:

How Orders Work#

1. Canonical Conversion#

All orders are converted to a single canonical form for matching:

Conversion Rules:

Buy YES @ p becomes BID @ p
Sell YES @ p becomes ASK @ p
Buy NO @ q becomes ASK @ (10000 - q)
Sell NO @ q becomes BID @ (10000 - q)

2. Tick Rounding#

Prices are rounded to the nearest tick (default 100 bps = 1%):

Side	Rounding	Reason
Bids	Round DOWN	Conservative for buyer
Asks	Round UP	Conservative for seller

Example (tick size = 100 bps):

Order	Before	After
Buy YES @ 6050	6050	6000 (round down)
Sell YES @ 5950	5950	6000 (round up)

3. Matching#

Orders match using price-time priority:

Placing a Buy Order#

Requirements#

Requirement	Description
Market State	Must be in TRADING state
Price	1 to 9999 basis points
Quantity	Greater than 0
Collateral	Sufficient USDC in wallet

Collateral Calculation#

For a buy order:

code

Required Collateral = (price_bps × quantity) / 10000

Example: Buy 100 YES @ 6000 bps

code

Collateral = (6000 × 100) / 10000 = 60 USDC

Order Flow#

Placing a Sell Order#

Requirements#

Requirement	Description
Market State	Must be in TRADING state
Share Ownership	Must own the shares you're selling
Price	1 to 9999 basis points
Quantity	Less than or equal to available shares

No Naked Shorts#

You can only sell shares you own:

Order Flow#

Self-Trade Prevention#

Orders from the same user cannot match against each other. If your new order would match your existing order, it skips and matches the next best price.

Order Parameters#

Parameter	Type	Description
`side`	OrderSide	BuyYes, SellYes, BuyNo, SellNo
`price_bps`	u16	Price in basis points [1, 9999]
`quantity`	u64	Number of shares
`order_type`	OrderType	Limit, PostOnly, IOC

Fee Structure#

Fee	Rate	Recipient
Taker Fee	200 bps (2.0%)	Split below
→ Protocol	150 bps (1.5%)	Treasury
→ Creator	50 bps (0.5%)	Market creator
Maker Fee	0 bps (0%)	—

Taker: Order that matches immediately Maker: Order that rests on the book

Order Book Visualization#

code

Market: BTC/USD (15-min duration)
         BIDS                    ASKS
Price    Qty     Total  |  Price    Qty     Total
-------------------------------------
5500     1,000   1,000  |  5600     500     500    <- Spread: 100 bps
5400     2,500   3,500  |  5700     1,200   1,700
5300     800     4,300  |  5800     3,000   4,700
5200     1,500   5,800  |  5900     750     5,450

Best Bid: 5500 bps (55%)
Best Ask: 5600 bps (56%)
Mid: 5550 bps

Trade Execution Example#

Incoming Order: Buy YES @ 5700 bps, qty = 1,000

Step	Match Price	Quantity	Cost
1	5600 bps	500	28.00 USDC
2	5700 bps	500	28.50 USDC
Total	5650 avg	1,000	56.50 USDC

Common Errors#

Error	Cause	Solution
`E_TRADING_NOT_STARTED`	Market not in TRADING state	Wait for start snapshot
`E_TRADING_ENDED`	Market past end time	Cannot trade after t_end
`E_INSUFFICIENT_COLLATERAL`	Not enough USDC	Deposit more USDC
`E_INSUFFICIENT_SHARES`	Selling more than owned	Reduce quantity
`E_WOULD_CROSS`	PostOnly order would match	Use Limit type
`E_ORDERBOOK_FULL`	64 orders per side limit	Wait for orders to fill

Best Practices#

Check the Spread: Wide spreads mean higher costs
Use Limit Orders: More control than market orders
Monitor Time: Orders are cancelled at market end
Calculate P&L: Know your breakeven price
Size Appropriately: Don't over-concentrate

Next Steps#

Learn Managing Positions
Understand Claiming Winnings