PolyOrderbooks Python SDK

Official Python client for the PolyOrderbooks API — historical Polymarket order books, prices, and liquidity metrics.

What is covered

Polymarket crypto markets: up/down rounds (5m, 15m, 4h), price thresholds, and related event markets. Order books are captured at 250ms resolution and resolved markets are stored alongside their winning outcome.

Every plan can query down to 250ms, including the free tier. Plans differ on history window and request volume — see pricing.

Install

pip install polyorderbooks

Or install the latest from GitHub:

pip install git+https://github.com/polyorderbookslabs/polyorderbooks-python.git

Quickstart

Get an API key from polyorderbooks.com/signup, then:

import os
from datetime import datetime, timedelta, timezone

from polyorderbooks import PolyOrderbooksClient

client = PolyOrderbooksClient(api_key=os.environ["POLYORDERBOOKS_API_KEY"])

# Or rely on POLYORDERBOOKS_API_KEY in the environment:
# client = PolyOrderbooksClient()

markets = client.list_markets(search="bitcoin", limit=5)
slug = markets["data"][0]["slug"]

end = datetime.now(timezone.utc)
start = end - timedelta(hours=6)

books = client.get_market_books(
    slug,
    start_ts=start.isoformat().replace("+00:00", "Z"),
    end_ts=end.isoformat().replace("+00:00", "Z"),
    resolution="1s",
    limit=100,
)

for outcome, points in books["data"].items():
    for point in points[:2]:
        bids = point.get("bids") or []
        asks = point.get("asks") or []
        best_bid = bids[0][0] if bids else None
        best_ask = asks[0][0] if asks else None
        print(point["t"], outcome, "bid", best_bid, "ask", best_ask)

client.close()

markets["data"] is a list of market objects. Each item includes more fields (public_id, volume, event_slug, …); the essentials look like:

[
    {
        "slug": "will-bitcoin-hit-150k-in-2026",
        "question": "Will Bitcoin hit $150k in 2026?",
        "status": "active"
    },
    {
        "slug": "fed-rate-cut-september-2026",
        "question": "Will the Fed cut rates in September 2026?",
        "status": "active"
    }
]

books["data"] is keyed by outcome label ("Yes", "No"), and each snapshot is {"t", "bids", "asks"}. Ladders are [price, size] pairs, best price first — bids descend, asks ascend. Depth varies per snapshot, so do not assume a fixed number of levels:

{
    "t": "2026-08-19T02:00:00Z",
    "bids": [[0.19, 147.34], [0.18, 63.69], [0.17, 277.77]],
    "asks": [[0.20, 13.6], [0.21, 152.17]]
}

A snapshot list can be empty for markets with no captures in the requested window, so guard before indexing bids[0] / asks[0].

Context manager usage:

with PolyOrderbooksClient() as client:
    usage = client.get_usage()
    print(usage["plan"], usage["limits"])

Pagination

Use metadata.next_cursor manually, or helpers:

for page in client.iter_market_books(
    slug,
    start_ts="2026-04-01T00:00:00Z",
    end_ts="2026-04-02T00:00:00Z",
    resolution="1s",
):
    process(page["data"])

API coverage

Authentication

Send your API key via the client constructor or POLYORDERBOOKS_API_KEY. The SDK sets X-API-Key on every request (the API also accepts Authorization: Bearer pob_…).

Errors

from polyorderbooks import AuthenticationError, NotFoundError, RateLimitError, APIError

• AuthenticationError — 401
• NotFoundError — 404
• RateLimitError — 429
• APIError — other HTTP failures

Every error carries status_code, message and the parsed body. RateLimitError also carries retry_after, the seconds the API asked you to wait:

import time

from polyorderbooks import RateLimitError

try:
    books = client.get_market_books(slug, start_ts=..., end_ts=..., resolution="1s")
except RateLimitError as err:
    time.sleep(err.retry_after or 1)

Development

python -m venv .venv
source .venv/bin/activate
pip install -e ".[dev]"
pytest

Links

• Product: polyorderbooks.com
• Docs: docs.polyorderbooks.com
• OpenAPI: docs.polyorderbooks.com/openapi.json

License

MIT — see LICENSE.