Nemi#

Nemi lets you test a trading strategy with paper money on real Polymarket prices. Sign up, pick a strategy, and it trades on its own: every order is filled against Polymarket's live order book, with Polymarket's fee, and paid out on Polymarket's own result. Nothing reaches Polymarket, and no real money is involved.

Nemi is an experiment, and it's separate from Layer: it reads Polymarket directly and doesn't use Layer's API or the SDK. For paper trading with the SDK, see Sandbox.

Two strategies on paper, Oct 27, on live Polymarket prices: +$223 after fees between them, counting the position vwap-rider still holds. vwap-rider's orders are bigger than its $1,000 wallet, so most are refused, and Nemi says so.

What it covers today#

• Polymarket's Bitcoin 15-minute markets only. Each one asks whether Bitcoin's price ends the 15 minutes up or down. Other venues and markets are greyed out for now.
• Paper money only. Each strategy you make gets its own paper wallet: you pick its starting money, from $1 to $10,000, and you can make up to 5.
• Strategies from templates. Start from one (Entry Bands, VWAP Rider, or a plain example), give it a starting balance, and it trades by itself, checking the market every 5 to 10 seconds, around the clock.

For each strategy you see its positions, every order with its fill or why it was refused, its settlements, its profit and loss after fees, and a report worked out from its orders. A status says whether it's running, idle, starved (it keeps placing orders but nothing has filled for an hour), stalled or errored, since when, and why.

How a paper order fills#

1. It waits half a second, about how long a real order takes to reach Polymarket.
2. It takes shares from the live book, best price first, the way a market order does. A limit price is the worst it accepts; nothing rests on the book.
3. It pays Polymarket's taker fee on every level it takes.

An order is refused, and the page says why, when the market has closed, the book is empty, the best price is past its limit, it's under Polymarket's minimum size, the wallet can't cover it, or Nemi's copy of the book is out of sync. If the book runs out first, the order fills in part.

How a window settles#

Polymarket resolves each window automatically, about 80 seconds after it closes, and Nemi pays $1 a winning share on that result. Each settlement also shows the prices that explain it: the start price, and Chainlink's 60-second average and last price at the close. It says when the side that led with 90 seconds left lost.

Good to know#

• Your orders don't move the book. Shares a paper order takes are still there for the next one, so a big order fills as if no one else were trading, and two strategies can take the same shares.
• Market orders only. There are no resting (maker) orders, so no maker fills or rebates.
• Open positions are valued at the price you could sell at now, after fees.
• A paper result isn't a promise. Real orders can fill differently, especially large ones.