Polymarket Paper Trading (2026): How to Practice for Free

Does Polymarket have paper trading?

Not as part of the exchange. Polymarket's developer documentation covers the live venue: market data, the order book, wallets and pUSD, the collateral token used for all trading. It describes no demo account and no simulated mode for traders, so any order you place with a funded account is a real trade.

That leaves practice to tools outside the exchange, from spreadsheets to home-made simulators. The hard part of any simulator is the fill: deciding honestly whether an order would really have traded, at what price and for how much. A simulator that fills every order at the midpoint teaches habits that the real book punishes.

How do you paper trade Polymarket with Predictefy?

Predictefy gives every account a simulated USD balance and a set of paper order routes that mirror the live ones. A paper engine fills your orders against the order books Predictefy already streams from Polymarket, so the prices and depth you practice against are the real ones. Nothing reaches Polymarket, and no wallet is involved.

1. Create a Predictefy API key and tick "Allow this key to place trades" to give it the trade scope.
2. Find a Polymarket market and the outcome you want to trade.
3. Place a paper order, then read your orders, positions and portfolio.

import { Predictefy } from '@predictefy/sdk';
import { randomUUID } from 'node:crypto';

const client = new Predictefy({ apiKey: process.env.PREDICTEFY_API_KEY });

const [market] = await client.polymarket.fetchMarkets({ query: 'election', status: 'active', sort: 'volume', limit: 1 });
const yes = market.outcomes.find((o) => o.side === 'yes') ?? market.outcomes[0];

const order = await client.placePaperOrder({
  venue: 'polymarket',
  marketId: market.marketId,
  outcomeId: yes.outcomeId,
  side: 'buy',
  price: 0.35,
  size: 50,
  tif: 'IOC',
  idempotencyKey: randomUUID(),
});

const positions = await client.paperPositions();
const portfolio = await client.paperPortfolio();

In Python, the same order is one call:

import uuid
from predictefy import Predictefy

client = Predictefy(api_key="pk_live_YOUR_KEY")

order = client.place_paper_order(
    "polymarket", "MARKET_ID", "OUTCOME_ID", "buy", 0.35, 50,
    tif="IOC",
    idempotency_key=str(uuid.uuid4()),
)
open_orders = client.list_paper_orders(status="open")

How realistic are paper fills on Polymarket?

Realistic in the direction that protects you. The fill engine, shared with Predictefy's backtester, is written to be pessimistic wherever the truth is uncertain:

• Depth is real. A marketable order walks Polymarket's displayed book level by level and pays each level's own price, so a large order sees the slippage it would see live.
• Resting orders wait for a genuine trade-through. The opposite quote has to cross strictly through your limit, since a mere touch would depend on queue position nobody can see.
• Size is shared. One order can take at most a quarter of the size shown at a price level per book update.
• Fees apply per fill, from verified venue fee schedules. Polymarket's fees vary by market category, which Polymarket fees explained breaks down.
• Old data never fills you. A book older than 30 seconds is treated as no evidence, and the order waits for a fresh one.

The outcome is PnL that is more likely to understate a strategy than flatter it, which is the right bias when the next step is real money.

What should you practice before trading Polymarket for real?

Paper trading is most useful when you use it to rehearse the specific things that cost money on the live exchange:

• Order type and size. How far a marketable order walks the book at your size, and when a resting limit order is the better choice. The Polymarket order book API shows what that depth looks like.
• Time in force. The difference between GTC, IOC and FOK when the book is thin.
• Safe retries. Paper orders require an idempotency key, exactly as live execution does, so a timed-out request resent with the same key returns the original order instead of placing a second one.
• Cancels and partial fills. Cancelling releases only the unspent part of a hold, so your accounting has to handle partially filled orders correctly.
• Reconciliation. Reading positions and portfolio totals back, and checking they match what your own code believes.

Between strategy versions, POST /v1/paper/account/reset restarts the simulation: working orders are cancelled, positions flattened and cash returned to its starting balance or to a new one you choose, while every past fill stays in history.

How much paper trading can you do for free?

All of it, within one limit. Paper trading is metered at 0 credits on every plan, and fills, cancels and resets are unlimited. The only per-plan difference is how many orders can be open at the same time: up to 10 on Free, 50 on Builder, 200 on Pro and no cap on Enterprise. The same account can paper trade other venues too, as shown in Kalshi paper trading, which makes it simple to rehearse a strategy that spans both.

How do you go from paper trading to live on Polymarket?

Three things change when the money becomes real. You need a funded Polymarket account, covered in every way to deposit on Polymarket. You need to know which of your addresses signs and which holds funds, explained in Polymarket wallet types. And you need an execution path.

For the execution path there are two good options. Polymarket's unified SDK handles signing and settlement for Polymarket alone, as shown in the Polymarket CLOB API guide. Predictefy's client-signed execution takes the same order parameters you used on paper, builds the order server side and has you sign it in your own process, so your keys never leave your control, across Polymarket and other venues. For a full bot on top of either, see how to build a Polymarket trading bot.

Frequently Asked Questions