Polymarket CLOBClient V2

1.0.0 verified Sat May 09 auth: no python

Python client for interacting with the Polymarket CLOB (Central Limit Order Book) V2 API. Version 1.0.0 is the latest stable release, with a release candidate 1.0.1rc1 available. Requires Python >=3.9.10. Maintained actively on GitHub.

pip install py-clob-client-v2

Common errors

error AttributeError: module 'py_clob_client' has no attribute 'ClobClient' ↓

cause Incorrect import path. `ClobClient` is under `py_clob_client.client`.

fix

Use from py_clob_client.client import ClobClient.

error py_clob_client.client.Credentials.__init__() got an unexpected keyword argument 'private_key' ↓

cause Passing private_key directly to ClobClient constructor (old style) instead of creating a Credentials object.

fix

Create a Credentials object first: creds = Credentials(private_key=key, chain_id=137) then pass to ClobClient.

error requests.exceptions.HTTPError: 401 Client Error: Unauthorized for url: https://clob.polymarket.com/... ↓

cause Invalid or missing credentials (private key not set, incorrect chain_id, or expired signature).

fix

Check that environment variable PRIVATE_KEY is set correctly and chain_id is 137 for Polygon Mainnet.

Warnings

gotcha The library's release versions do not follow strict semver; 1.0.1rc1 is a pre-release and may contain breaking changes. ↓

fix Pin to 1.0.0 for production unless you need the features in 1.0.1rc1.

gotcha Private key must be in hex format without 0x prefix. Incorrect formatting will cause silent failures. ↓

fix Ensure private key is a hex string (64 characters) without '0x'.

deprecated The `getHeartbeat()` method (camelCase) is deprecated in v1.0.0; use `get_heartbeat()` instead. ↓

fix Replace `getHeartbeat()` with `get_heartbeat()`.

breaking In v1.0.0, the `Credentials` class was introduced and the constructor changed. Passing a raw private key string directly is no longer supported. ↓

fix Use from py_clob_client.clob_types import Credentials and pass Credentials object.

Imports

ClobClient

from py_clob_client.client import ClobClient

PolymarketCredentials

from py_clob_client.client import Credentials

Quickstart

Initialize a ClobClient with private key from environment variable and test connectivity.

import os
from py_clob_client.client import ClobClient
from py_clob_client.clob_types import Credentials

host = "https://clob.polymarket.com"
key = os.environ.get('PRIVATE_KEY', '')
creds = Credentials(private_key=key, chain_id=137)
client = ClobClient(host=host, credentials=creds)
print(client.get_heartbeat())