Rust
The matching engine and core services are written in Rust. Price-time priority, one book per market, no garbage-collector pauses.
Private preview · Simulated money
Pick a side. See the whole price.
Onsides is the prediction exchange built on the trader’s side. Price, fee and slippage, itemized before you click. To the hundredth of a cent.
Simulated money. Real matching engine. Real order books.
01 · The problem
Prediction markets look simple. A price. A yes. A no. Then the fee shows up. Then the spread. Then the slippage. By the time you see what you paid, you already paid it. Onsides puts the whole price on the ticket before you trade. Every number. Every time.
YES
Every question has a yes.
NO
Every yes has a no.
We stand on the line between them, and we draw it in public.
02 · The hook
Check your fees.
Then check ours.
One published formula. Rounded up to the hundredth of a cent, never to the next penny. Move the sliders. The receipt is the whole story.
Ticket previewBuy 100 YES at 60¢
Price$60.00
Fee$1.68
Slippagewalks the live book in the demo
All-in if it fills now$61.68
Pays if YES$100.00
Try it on a real book
Demo fee schedule. Final fees are set at launch and published before anyone trades.
03 · Under the hood
Built like an exchange.
Not like an app.
0 µ$
Money left unaccounted for after our end-to-end settlement runs. Every millionth of a dollar reconciles.
Double‑entry
Every balance lives in TigerBeetle, a ledger database built for financial accounting. Debits equal credits, always.
Replayable
Every order is journaled to Redpanda before it’s acknowledged. Rebuild any book, any moment, from the log.
Watched
Market-surveillance detectors run from day one, with an alert queue and case files. Fair markets are designed, not hoped for.
All‑in
Price, fee and slippage on every ticket, before you confirm. That’s the product.
04 · The board
Every question,
priced in public.
Sports
Home side wins tonight?
YES 64¢ NO 36¢
Economics
Rate cut at the next Fed meeting?
YES 41¢ NO 59¢
Crypto
Bitcoin above its yearly high by Friday?
YES 22¢ NO 78¢
Weather
Rain in Seattle tomorrow?
YES 78¢ NO 22¢
Illustrative questions and prices. The demo runs live, simulated books for sports, economics, crypto and weather.
A fair shot. A fair market.
See it
trade.
The demo is the real engine with simulated money. Place an order, watch it fill, read the receipt.