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clob-client

type: entityconfidence: highupdated: 2026-07-07sources: 2

Overview

clob-client is the TypeScript client for the Polymarket CLOB -- Polymarket/clob-client, published on npm as @polymarket/clob-client. It signs and posts orders and reads market data against https://clob.polymarket.com.

[!WARNING] This repository has been archived and is no longer maintained. The client is no longer functional and should not be used for new or existing integrations. Please migrate to our new unified SDK: https://github.com/Polymarket/ts-sdk

The newer generation client is @polymarket/clob-client-v2 (see authentication); the Python counterpart is py clob client.

Characteristics

  • Language: TypeScript / Node.
  • Signer via ethers Wallet (private key) or a viem WalletClient.
  • funder is your Polymarket Profile Address (where you send USDC).
  • signatureType: 0 Browser Wallet (MetaMask, Coinbase Wallet, etc.), 1 Magic/Email Login.
  • Order placement needs the market's tickSize and negRisk flag, obtained from the Gamma Markets API get-markets endpoint.
  • By default API errors return as { error, status } objects; pass throwOnError: true as the last constructor argument to throw ApiError.

How to Use

Install (from the README usage comments):

// npm install @polymarket/clob-client
// npm install ethers

Client initialization and placing a GTC order:

import { ApiKeyCreds, ClobClient, OrderType, Side, } from "@polymarket/clob-client";
import { Wallet } from "@ethersproject/wallet";

const host = 'https://clob.polymarket.com';
const funder = ''; // This is your Polymarket Profile Address, where you send UDSC to. 
const signer = new Wallet(""); // This is your Private Key. If using email login export from https://reveal.magic.link/polymarket otherwise export from your Web3 Application


// In general don't create a new API key, always derive or createOrDerive
const creds = new ClobClient(host, 137, signer).createOrDeriveApiKey();

//0: Browser Wallet(Metamask, Coinbase Wallet, etc)
//1: Magic/Email Login
const signatureType = 1; 
  (async () => {
    const clobClient = new ClobClient(host, 137, signer, await creds, signatureType, funder);
    const resp2 = await clobClient.createAndPostOrder(
        {
            tokenID: "", //Use https://docs.polymarket.com/developers/gamma-markets-api/get-markets to grab a sample token
            price: 0.01,
            side: Side.BUY,
            size: 5,
        },
        { tickSize: "0.001",negRisk: false }, //You'll need to adjust these based on the market. Get the tickSize and negRisk T/F from the get-markets above
        //{ tickSize: "0.001",negRisk: true },

        OrderType.GTC, 
    );
    console.log(resp2)
  })();

Using a viem WalletClient instead of ethers:

import { ClobClient } from "@polymarket/clob-client";
import { createWalletClient, http } from "viem";
import { polygon } from "viem/chains";
import { privateKeyToAccount } from "viem/accounts";

const host = "https://clob.polymarket.com";
const account = privateKeyToAccount("0x...");
const walletClient = createWalletClient({
    account,
    chain: polygon,
    transport: http(),
});

const clobClient = new ClobClient(host, 137, walletClient);

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