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Market makers interact with Polymarket through the CLOB API — posting two-sided quotes, managing inventory across markets, and rebalancing positions. The SDK clients handle order signing and submission, so you can focus on strategy.
This page covers MM-specific workflows and best practices. For full order mechanics, see Create Orders and Cancel Orders.

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Two-Sided Quoting

The core market making workflow is posting a bid and ask around your fair value. Use createAndPostOrder to place each side: 
import { ClobClient, Side, OrderType } from "@polymarket/clob-client";

const client = new ClobClient(
  "https://clob.polymarket.com",
  137,
  wallet,
  credentials,
  signatureType,
  funder,
);

// Bid at 0.48
const bid = await client.createAndPostOrder({
  tokenID: "3409705850427531082723332342151729...",
  side: Side.BUY,
  price: 0.48,
  size: 1000,
  orderType: OrderType.GTC,
});

// Ask at 0.52
const ask = await client.createAndPostOrder({
  tokenID: "3409705850427531082723332342151729...",
  side: Side.SELL,
  price: 0.52,
  size: 1000,
  orderType: OrderType.GTC,
});

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Batch Orders

For tighter spreads across multiple levels, use postOrders to submit up to 15 orders in a single request: 
const orders = await Promise.all([
  client.createOrder({ tokenID, side: Side.BUY, price: 0.48, size: 500 }),
  client.createOrder({ tokenID, side: Side.BUY, price: 0.47, size: 500 }),
  client.createOrder({ tokenID, side: Side.SELL, price: 0.52, size: 500 }),
  client.createOrder({ tokenID, side: Side.SELL, price: 0.53, size: 500 }),
]);

const response = await client.postOrders(
  orders.map((order) => ({ order, orderType: OrderType.GTC })),
);
Batching reduces latency by submitting multiple quotes in a single request. Always prefer postOrders() over multiple individual createAndPostOrder() calls.

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Choosing Order Types

TypeBehaviorWhen to Use
GTCRests on the book until filled or cancelledDefault for passive quoting
GTDAuto-expires at a specified timeExpire quotes before known events
FOKMust fill entirely and immediately, or cancelAggressive rebalancing — all or nothing
FAKFills what’s available immediately, cancels restRebalancing where partial fills are OK
GTC and GTD are your primary tools for passive market making — they rest on the book at your specified price. FOK and FAK are for rebalancing inventory against resting liquidity.

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Time-Limited Quotes with GTD

Auto-expire quotes before known events like market close or resolution: 
// Expire in 1 hour
const expiringOrder = await client.createOrder({
  tokenID,
  side: Side.BUY,
  price: 0.5,
  size: 1000,
  orderType: OrderType.GTD,
  expiration: Math.floor(Date.now() / 1000) + 3600,
});

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Managing Orders

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Cancelling

Cancel individual orders, by market, or everything at once: 
await client.cancelOrder(orderId); // Single order
await client.cancelOrders(orderIds); // Multiple orders
await client.cancelMarketOrders(conditionId); // All orders in a market
await client.cancelAll(); // Everything
See Cancel Orders for full details including onchain cancellation.

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Monitoring Open Orders

const order = await client.getOrder(orderId);

const orders = await client.getOpenOrders({
  market: "0xbd31dc8a...",
  asset_id: "52114319501245...",
});

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Tick Sizes

Your order price must conform to the market’s tick size, or it will be rejected. Look it up with the SDK before quoting: 
const tickSize = await client.getTickSize(tokenID);
// Returns: "0.1" | "0.01" | "0.001" | "0.0001"

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Fees

Most markets have zero fees for both makers and takers. However, the following market types have taker fees:
  • 5-minute crypto markets
  • 15-minute crypto markets
  • Select sports markets (e.g., NCAAB, Serie A)
See Fees for the full fee schedule and calculation details.

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Best Practices

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Quote Management

  • Quote both sides — Post bids and asks to earn maximum liquidity rewards
  • Skew on inventory — Adjust quote prices based on your current position to manage exposure
  • Cancel stale quotes — Pull orders immediately when market conditions change
  • Use GTD for events — Auto-expire quotes before known catalysts to avoid stale exposure

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Latency

  • Batch orders — Use postOrders() to submit multiple quotes in a single request
  • WebSocket for data — Subscribe to real-time feeds instead of polling REST endpoints

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Risk Controls

  • Size limits — Check token balances before quoting and don’t exceed your available inventory
  • Price guards — Validate prices against the book midpoint and reject outliers
  • Kill switch — Call cancelAll() immediately on errors or position breaches
  • Monitor fills — Subscribe to the WebSocket user channel for real-time fill notifications

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Next Steps

Inventory

Split, merge, and redeem outcome tokens

Liquidity Rewards

Earn rewards for providing two-sided liquidity

Create Orders

Full order creation reference with all options