# py-clob-client

Polymarket's own Python CLOB client - archived, and declared non-functional by its README.

*https://predictionmarkets.tools/tools/py-clob-client · Trading Clients, SDKs & Bots*

## Facts

### At a glance

| Field | Value |
| --- | --- |
| Vendor | Polymarket |
| Category | Trading Clients, SDKs & Bots |
| Job | sdk |
| Website | https://github.com/Polymarket/py-clob-client |
| Pricing model | open-source |
| Free tier | true |
| Open source | true |
| Licence | MIT |
| Self-hosted | true |
| Tested hands-on | false |
| Last updated | 2026-09-19 |

### Availability

| Field | Value |
| --- | --- |
| Jurisdictions | global |
| Open to US persons | true |
| KYC required | false |

### Markets

| Field | Value |
| --- | --- |
| Settlement | crypto |
| Resolved by | none |

### Economics

| Field | Value |
| --- | --- |
| Taker fee | none |
| Maker fee | none |
| Liquidity model | clob |
| Platforms | library |
| AI features | none |

### Interfaces

| Field | Value |
| --- | --- |
| API | true |
| WebSocket | false |
| Scripting | none |
| Python | true |
| MCP server | false |
| Export | json |

### Capabilities

Yes: order_book, automation, live_trading

No: charting, screening, backtesting, paper_trading, portfolio_tracking, calibration_scoring, cross_venue, alerts, news, tax_reporting

*Verified: pricing 2026-09-19; availability 2026-09-19; capabilities 2026-09-19.*

## What it is

**Do not start here.** This package is archived and Polymarket says it does not work: the README
opens with a warning that the repository is no longer maintained, that the client is no longer
functional, and that it should not be used for new or existing integrations, followed by "Please
migrate to our new unified SDK". The migration target is [`polymarket-client`](https://predictionmarkets.tools/tools/polymarket-client) on PyPI, developed in
`Polymarket/py-sdk`. Migrating is not optional - nothing here is going to be fixed.

What it was: a Python client for the Polymarket Central Limit Order Book, published by Polymarket
itself - the repository sits in the Polymarket GitHub organisation and the PyPI package names
Polymarket Engineering as its author. It was the reference way to place orders on Polymarket from
Python, and it is what most third-party Polymarket bots were built on. The card stays in the
catalogue because the package is still installable, still the answer most search results give, and
still the thing a reader will find first - and because the PyPI page carries no warning at all, so
`pip install py-clob-client` succeeds today with nothing to tell you.

What it did, while it worked - the method inventory is still readable in the archived source:

- **Order signing.** EIP-712 typed-data signing of orders in `py_clob_client/signing/eip712.py`,
  with HMAC request signing for the authenticated Level 2 endpoints in `signing/hmac.py`. Three
  signature types were supported - a plain EOA, an email or Magic wallet, and a browser-wallet
  proxy - because on Polymarket the key that signs is often not the address that holds the funds.
- **API credentials.** `create_api_key`, `derive_api_key` and `create_or_derive_api_creds` derived
  the Level 2 credential set from the wallet key, plus read-only key management.
- **Market data.** Midpoints, prices, spreads, tick sizes, order books in bulk, last trade prices
  and the simplified market listing.
- **Orders.** `create_order` and `create_market_order` with GTC, GTD, FOK and FAK order types,
  `post_order` and `post_orders`, `cancel`, `cancel_orders`, `cancel_all` and `cancel_market_orders`,
  plus a heartbeat endpoint.
- **Balance and allowance.** `get_balance_allowance` and `update_balance_allowance`, which read and
  refresh the CLOB's own accounting of what your address has available.
- **RFQ.** A separate request-for-quote client under `py_clob_client/rfq/`.

## Availability

The package itself has no geography. It installs from PyPI anywhere pip works, needs Python 3.9.10
or newer, and its read-only calls require no account, no key and no KYC - `ClobClient(host)` with no
credentials answers midpoint, price and order-book queries. The `us_persons` and `kyc_required`
flags on this card describe the library, not the exchange behind it.

Who may actually hold a funded Polymarket position, and under what terms, is a question about
Polymarket rather than about this package, and it is answered on the venue's own card. A library
imposes no jurisdiction and grants none.

## Pricing

Free, MIT-licensed, nothing to buy and nothing metered. The GitHub repository and the PyPI
classifier agree on MIT.

The library charges nothing; what a fill costs is Polymarket's fee schedule, which the client
merely read back through `get_fee_rate_bps`. Those numbers belong on the venue's card, not here.

## Markets & resolution

A client resolves nothing. Orders placed through it reached Polymarket's CLOB and settled in USDC
on Polygon like any other order on that book, and who decides the outcome is entirely the venue's
question - this package neither read the resolution nor had an opinion about it. The subject
row on this card is blank on purpose - the questions reachable through the client are whatever
Polymarket lists, the library narrowed nothing, and we have not surveyed that list for this card.

Two details of the data model mattered in practice. Prices were dollars from 0.00 to 1.00 per
share, so a "price" here is a probability. And the tradeable unit was a token ID, one per outcome,
which had to come from Polymarket's Gamma markets API rather than from this client - the CLOB client
took token IDs and did not discover them. See [polymarket-gamma-api](https://predictionmarkets.tools/tools/polymarket-gamma-api)
for the discovery half and [polymarket-clob-api](https://predictionmarkets.tools/tools/polymarket-clob-api) for the endpoints this
package wrapped.

## Integrations

Seven runtime dependencies - `eth-account`, `eth-utils`, `poly_eip712_structs`, `py-order-utils`,
`python-dotenv`, `py-builder-signing-sdk` and `httpx[http2]`. That is a signing stack, which is the
right way to read it - the package holds your wallet private key in process in order to sign orders
locally, and posts signed payloads rather than credentials.

No WebSocket. No CLI. No MCP server. It is a library and nothing else, and every integration built
on it is somebody's own code.

## Limitations

**It is archived and its own publisher says it does not work.** That is the whole limitation and
everything else is detail. The repository is read-only, the last commit on `main` is dated
2026-05-25, and the last release, v0.34.6, is dated 2026-02-19. A hundred issues are open and will
stay open. Nothing will be fixed when Polymarket next changes its API, because nobody is holding
the other end.

**It never set on-chain allowances.** Users signing with a plain EOA wallet had to approve USDC and
the conditional-token contract for three separate exchange contracts before any order would fill,
and the README handled this by naming the contract addresses and linking a gist. That was the most
common first failure for new users, and it was outside the library.

**It polled.** No WebSocket support, despite Polymarket's CLOB running both a market channel and a
user channel. Anything that needed live book updates had to be written separately.

**It was not a discovery tool.** No event or market search - you arrived with a token ID or you did
not trade.

## Alternatives

Polymarket's replacement is its unified SDK, developed in the `Polymarket/py-sdk` repository and
installed from PyPI as [`polymarket-client`](https://predictionmarkets.tools/tools/polymarket-client). It is MIT-licensed, needs Python 3.11 or newer, ships
synchronous and asynchronous clients, and was at version 0.10.0 on 2026-09-10 after 34 releases
since May 2026. It is the migration target the archived README names, and it is
carded here.

Watch the install name. `polymarket` and `polymarket-sdk` are both taken on PyPI by unrelated
authors publishing unrelated things; neither is Polymarket's.

If the goal is several venues rather than this one, [ccxt](https://predictionmarkets.tools/tools/ccxt) reaches Polymarket's CLOB
through its prediction namespace, including the WebSocket channels this client never had. If the
goal is only to read prices, [polymarket-clob-api](https://predictionmarkets.tools/tools/polymarket-clob-api) and
[polymarket-gamma-api](https://predictionmarkets.tools/tools/polymarket-gamma-api) are plain HTTP and need no client library at
all.

## FAQ

### Is py-clob-client still usable?

No, according to Polymarket. The repository was archived and its README now opens with a warning that the client is no longer functional and should not be used for new or existing integrations. The last release was v0.34.6 on 2026-02-19 and the last commit on main was 2026-05-25.

### What replaced py-clob-client?

Polymarket's unified Python SDK, published from the Polymarket/py-sdk repository and installed from PyPI as [polymarket-client](/tools/polymarket-client). It is MIT-licensed, requires Python 3.11 or newer, and ships both a synchronous and an asynchronous client. Version 0.10.0 was published on 2026-09-10.

### Did py-clob-client set token allowances for you?

Not the on-chain ones. It could read and refresh the CLOB's own view of your balance and allowance, but the ERC-20 approvals that let the exchange contracts move your USDC and conditional tokens had to be sent separately - the README pointed at an external gist for that code.

### Did py-clob-client support WebSocket streaming?

No. The package shipped no WebSocket module and the README documented none, so order books and prices had to be polled over REST even though Polymarket's CLOB exposes market and user WebSocket channels.

## Also from Polymarket

- [Polymarket CLI](https://predictionmarkets.tools/tools/polymarket-cli.md)
- [polymarket-client](https://predictionmarkets.tools/tools/polymarket-client.md)
- [Polymarket CLOB API](https://predictionmarkets.tools/tools/polymarket-clob-api.md)
- [Polymarket Gamma API](https://predictionmarkets.tools/tools/polymarket-gamma-api.md)
- [Polymarket US API](https://predictionmarkets.tools/tools/polymarket-us-api.md)
- [Polymarket US Python SDK](https://predictionmarkets.tools/tools/polymarket-us-python.md)
- [Polymarket US TypeScript SDK](https://predictionmarkets.tools/tools/polymarket-us-typescript.md)
- [Polymarket US](https://predictionmarkets.tools/tools/polymarket-us.md)
- [Polymarket](https://predictionmarkets.tools/tools/polymarket.md)

## Background

- [What running a bot does not solve](https://predictionmarkets.tools/guides/what-a-bot-cannot-fix.md) — A bot fixes speed and consistency. Rate limits, a missing rehearsal, a field that stops arriving, a partial fill and a paused market are not coding problems.

- [Where your key lives when software trades for you](https://predictionmarkets.tools/guides/where-your-key-lives.md) — Four different credentials are all called a key, and they differ in what a copy permits. What the clients in this catalogue ask for, and what to ask them back.

## Also worth comparing

- [CCXT](https://predictionmarkets.tools/tools/ccxt.md) — One client for seven prediction venues, inside a 104-exchange crypto library.
- [limitless-sdk](https://predictionmarkets.tools/tools/limitless-sdk.md) — Limitless Exchange's own async Python SDK - CLOB and NegRisk orders, WebSocket, MIT.
- [PMXT](https://predictionmarkets.tools/tools/pmxt.md) — CCXT-shaped client for prediction markets, with a hosted API and a self-hosted mode.
- [Kalshi Python SDK (sync and async)](https://predictionmarkets.tools/tools/kalshi-python-sync.md) — Kalshi's current official Python client - weekly releases, Python 3.13 only, no source.
- [kalshi-python](https://predictionmarkets.tools/tools/kalshi-python.md) — Kalshi's own generated Python client - closed-source, and unreleased since September 2025.
- [pykalshi](https://predictionmarkets.tools/tools/pykalshi.md) — Unofficial Kalshi client with what the generated SDK leaves out - streams and retries.