An automated market maker for DreamDEX Event Contracts on Somnia. It rests a bid on both outcomes of a binary market, holds no inventory, and takes no view on the underlying.
The arithmetic
A binary market resolves one way or the other. One outcome pays 1, the other pays 0, so holding both is worth exactly 1 at settlement, whatever happens in the world. Buy the pair for less than that and the difference is yours. No price move can take it, because you are not exposed to price.
Selling an outcome you don't own reverts. There is no naked short. Buying both needs only collateral, and the venue mints the pair when two opposite-side buyers cross. So the maker never holds inventory.
The order book includes your own resting order, so quoting one tick inside the best bid means outbidding yourself, a ratchet that walks the edge to zero. Quotes are capped so a pair never costs more than the floor allows.
If one bid fills and the other doesn't, you're briefly exposed. The loop completes the pair by crossing, but only while the total stays under 1. Above that it holds the position and says so.
The instrument
Up and Down stack toward a fixed 1.000 and the space left over is the edge. That gap is genuinely one to three points, so a true-scale column shows a sliver. Rather than inflate it, a vernier expands the last five points alongside, where the same quantity is legible. Coarse for honesty, fine for reading.
Three minutes
Live on testnet: quotes resting on both outcomes, a leg filling, the pair being completed, and settlement paying out.
Proof
Nothing on this page is a mock-up. These are real, on Somnia Shannon, and every one is clickable.
| What | Transaction |
|---|---|
| Complete set minted, 1 tUSDC → 1 Up + 1 Down | 0x63fa4e26 |
| Merged back, exact, no leakage | 0x210c57e4 |
| First maker order resting | 0x29f61034 |
| Up leg filled | 0x6b1de65d |
| Down leg filled | 0x339a4102 |
| Winnings redeemed, +20.000 tUSDC | 0xb785b4f0 |
Limits
Stated plainly, because they're the first things worth asking.