py-clob-client-v2

What it is and what it does

py-clob-client-v2 is a Python REST client for Polymarket's CLOB, enabling programmatic order placement and management on prediction markets. It handles two-tier authentication: L1 wallet signing (EIP-712) to derive API credentials, and L2 HMAC signing for subsequent order operations. The library wraps Polymarket's REST API with native support for limit orders (GTC), market orders (FOK/FAK), and account queries.

The package is built on eth-account, eth-abi, eth-utils, and httpx for blockchain interaction and HTTP communication. It's actively maintained (last commit 2026-08-05) and requires Python >=3.9.10. The maintainers note that a unified SDK (py-sdk) now combines REST and WebSocket APIs, suggesting this package may be superseded for new projects, though it remains functional for CLOB-specific workflows.

Use it for:

• Place limit buy/sell orders on Polymarket prediction markets with custom price and size parameters
• Execute market orders with immediate-or-cancel (FOK) or fill-as-much-as-possible (FAK) semantics using USDC
• Automate wallet-based authentication and API credential derivation for programmatic trading workflows
• Monitor account balances and order status via authenticated REST endpoints
• Build trading bots that sign orders with an Ethereum private key and submit them to the CLOB

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

Python client library for placing and managing orders on Polymarket's CLOB (central limit order book) via REST API, with built-in wallet authentication and order execution.

Yes, if you are actively trading on Polymarket's CLOB and need a Python REST client. The package is actively maintained, has low install friction, and provides the core order-placement and authentication layer. However, note the maintainers' recommendation to use py-sdk for new projects—evaluate whether you need CLOB-specific functionality or would benefit from the unified SDK's broader API coverage and WebSocket support.

Install

py-clob-client-v2 on PyPI

pip install py-clob-client-v2

uv add py-clob-client-v2

poetry add py-clob-client-v2

Installing py-clob-client-v2

Before you install

Low friction: pure Python wheel with six runtime dependencies (eth-account, eth-abi, eth-utils, poly_eip712_structs, py-order-utils, httpx). Active maintenance—last commit 2026-08-05, released 2026-07-17, 28 days ago. Requires Python >=3.9.10.

License in practice

MIT license (permissive). You can use, modify, and distribute this package freely in commercial or private projects with minimal restrictions.

Quickstart

pip install py-clob-client-v2

import os
from py_clob_client_v2 import ClobClient, OrderArgs, Side, OrderType, PartialCreateOrderOptions

client = ClobClient(host="<host>", chain_id=137, key=os.environ["PK"])
creds = client.create_or_derive_api_key()
client = ClobClient(host="<host>", chain_id=137, key=os.environ["PK"], creds=creds)
resp = client.create_and_post_order(
    order_args=OrderArgs(token_id="", price=0.4, side=Side.BUY, size=100),
    options=PartialCreateOrderOptions(tick_size="0.01"),
    order_type=OrderType.GTC
)

Requires a private key (PK environment variable) for wallet authentication and a Polymarket CLOB host URL. Chain ID must be set to 137 (mainnet) or 80002 (Amoy testnet).

Verify before relying

• Whether the package supports both limit and market orders with all documented order types (GTC, FOK, FAK) as shown in examples
• Real-world latency and reliability characteristics for order placement under load
• Whether the unified py-sdk mentioned in the note is a replacement or complementary to this package

Package facts

Evidence: py_clob_client_v2-1.1.0-py3-none-any.whl

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