250ms Polymarket order books — free tier includes L2

Full bid/ask depth for Polymarket crypto and sports markets — 1.16M markets, captured every 250ms. Query books, prices, and liquidity through a REST API, Python SDK, or MCP server — not just midpoints.

Get startedAPI docsPricing
1.16M markets · snapshotted on a 250ms tickIndependent · not affiliated with Polymarket
Crypto + sports250ms captureL2 on free tierMCP serverBacktest AI

Research dataset

The Polymarket L2 dataset you can cite in a paper

897k order book snapshots at 1-second resolution, registered on Zenodo (10.5281/zenodo.22084114, August 2026) with a DataCite DOI and CC BY 4.0 licence. Free to download — valid in a data availability statement. Paid archives typically offer no persistent identifier.

  • 897k L2 snapshots
  • 805 resolved markets
  • CC BY 4.0 licence

How to citeAll datasets

Published on

Side by side

Why 250ms L2 beats minute archives

Polymarket's API is great for live prices. Typical historical archives sample once per minute. We capture full bid/ask depth every 250ms — built for crypto backtests and final-minute settlement research.

FeaturePublic APITypical paid archivesPolyOrderbooks
Historical L2 order booksCurrent book only1-minute snapshots (typical)250ms full ladders
Free tier order booksNo archiveOften none on freeYes — Starter includes L2
Finest query resolution1-minute prices1 minute250ms on every plan
AI / MCP accessBuild your own wrapperNo official MCPOfficial MCP server
Paid entry (L2 archive)N/AFrom ~$60/mo (typical)Data from $19/mo (30-day window)

Backtest AI

Backtest a Polymarket strategy in plain English

Describe a crypto up/down strategy in a sentence — “Buy DOWN on BTC 15m below 0.40, take profit at 0.55, stop loss at 0.30” — and Backtest AI turns it into executable rules and replays it over resolved Polymarket markets from the PolyOrderbooks archive.

  • No strategy code — natural language becomes entry and exit rules.
  • Fills walk the historical 250ms L2 book, so runs reflect partial fills, slippage, and exit reasons instead of an assumed mid price.
  • A report plus an AI analysis — net P&L, win rate, profit factor, max drawdown, equity curve, and a plain-English read of what worked.
  • Save backtests, export trades to CSV or the full report to JSON, and keep the conversation in your workspace.
118,251resolved crypto up/down markets
143.5ML2 order book snapshots
250mscapture across the archive
Try Backtest AIHow the API works

How it works

Three steps. One API. Your client never talks to live Polymarket.

01 · Discover

Find a market

Search markets with the discovery APIs. Get the slug, outcomes, and status — open or already resolved.

02 · Request a window

Pull prices and metrics

Choose a time range and resolution. Prices and liquidity use the same window so your charts and filters stay aligned.

03 · Replay depth

Walk the order book

Load historical bid/ask levels to estimate fills and slippage — detail a mid-price series cannot give you.

What we store

Indexed crypto and sports markets with order books, prices, and metrics captured on the same 250ms timeline.

Connecting…
1.16Mmarkets indexed
2.52Border book snapshots
590.81Mprice snapshots
1.36Bmetrics snapshots
GET/markets/bitcoin-all-time-high-by-december-31-2026/books
start_tsend_tsresolutionlimitcursor

Full bid and ask ladders as [price, size] for each outcome.

Sample marketbitcoin-all-time-high-by-december-31-2026
2026-04-01T00:00:00Z
Mid0.052
Spread0.001
Resolution1s

Bids

Size
0.0525,645
0.051425
0.0501,011
0.049644

Asks

Size
0.0531,134
0.0581,085
0.0597,058
0.0601,428
/markets/bitcoin-all-time-high-by-december-31-2026/bookscount 100 · limit 100

How to connect

Query it, code it, or export it

Choose how you want to pull historical data — REST API, Python SDK, MCP for AI clients, or Enterprise S3 bulk export.

REST API

Markets, books, prices, and metrics over HTTPS — one API key, any language.

Python SDK

Official PyPI client (polyorderbooks) for scripts, notebooks, and backtests.

MCP server

250ms L2 order books in Cursor and Claude — official MCP server.

Enterprise S3 export

Sales-assisted bulk drops in Parquet, CSV, or JSON — one-time or on a schedule.

First time here? Read the API quickstart, then pick a path above.

Plans — 250ms resolution on every tier

Free Starter includes order books. Upgrade for longer history and higher rate limits.

Starter

$0

Start free — no credit card required.

  • Full Polymarket crypto and sports coverage — 1.16M markets
  • Discovery, order books, prices, and metrics
  • Finest resolution: 250ms
  • 60 requests/min · 1,000/day
  • 3 days of history
  • 1 free AI backtest
  • 3 free strategy backtests
Get started

Build your plan

$19/mo

Pick a history window, then add speed and Backtest AI as needed.

History window

Speed

300 requests/min · 50,000/day

  • Coverage: 1.16M crypto and sports markets
  • Finest resolution: 250ms
  • 300 requests/min · 50,000/day
  • 30 days of history
Get started

Pay by card or crypto

Backtest AI

$29/mo

Write your idea in plain English. We'll tell you if it's a money-maker.

  • Strategy backtests — Unlimited
  • AI backtests — 500 / month
  • 8 crypto coins — BTC, ETH, SOL, XRP, HYPE, BNB, DOGE, ZEC
  • 70k+ resolved markets to backtest
  • Replays crypto up/down strategies. Sports order books are in the data plans.
  • AI-generated strategy analysis
  • 30 days of market data for AI
  • Data API access
Get started

Pay by card or crypto

Enterprise

Custom

Full data dumps, custom feeds, and bespoke delivery.

  • S3 exports and dedicated support
  • Custom rate limits, history, and granularity
  • Private or dedicated access
  • SLA and onboarding
Talk to us

Full plan details → · Polymarket API pricing comparison →

One catalog, two categories

Polymarket crypto and sports are served from the same base URL, with the same API key and the same response shape. Add category=crypto or category=sports to narrow a request, or omit it to page across both.

1.16M markets2.52B L2 snapshots360 series974k resolvedSince 2023-01-03

Sports data →

More than 700,000 markets across 226 series — soccer, MLB, tennis, NFL and NCAA football, esports, golf, hockey and more. Moneyline, spread, total, exact score, and prop contracts, all at 250ms L2.

Crypto data →

Up/Down intervals at 5m, 15m, and 4h, price thresholds, and event-linked markets across 134 series. History back to 2023-01-03, which is the deepest window we hold.

Built for trading and research

Mid prices are easy to chart. Depth is what tells you whether a trade would have filled.

DiscoveryPrices & metricsL2 order booksResolved marketsAPI docs →

Simulate fills

Walk historical bid and ask levels when you size an order. Spot thin books and wide spreads before a backtest looks too clean.

Match signals to liquidity

Pull prices and metrics on the same window as the book. Focus on times the market was deep enough to trade.

Keep settled markets

After an event resolves, the market stays in our archive — including the winner — so you can still study it.

FAQ

Short answers before you open the docs. See all questions →

How is this different from the live Polymarket API?

The live API shows what is happening now. PolyOrderbooks stores history — past order books, prices, and liquidity — so you can replay a market after it has moved on.

How often do you capture data?

Open markets are snapshotted every 250ms. Every plan, including the free Starter tier, can query down to 250ms. Coarser buckets (1s–1d) are available on every plan.

Can I backtest Polymarket strategies with historical order books?

Yes. Use L2 bid and ask ladders to estimate fills and slippage instead of relying on mid prices alone. Pull prices and metrics on the same time window so signals and liquidity stay aligned.

Do I need a dashboard?

No. PolyOrderbooks is an API product. Use the dashboard for keys and usage; the full API reference is at docs.polyorderbooks.com — your integrations call the REST API directly.

Do you have a Python SDK?

Yes. The official polyorderbooks package is on PyPI (pip install polyorderbooks). Runnable examples live on GitHub. REST remains the core API; the SDK wraps the same endpoints.

Do you have an MCP server for Cursor or Claude?

Yes. @polyorderbooks/mcp-server on npm exposes historical order books, prices, and metrics as MCP tools in Cursor, Claude Desktop, and other MCP clients. Same 250ms archive as the REST API — install steps at polyorderbooks.com/polymarket-mcp-server.

How do I get access?

Create an account, verify your email, and generate an API key from the dashboard. Plan limits are enforced on the hosted API — see pricing and the docs to get started.

Is this affiliated with Polymarket?

No. PolyOrderbooks is an independent data product and is not affiliated with or endorsed by Polymarket.

Start with a free plan

Create an account, read the docs, and call the API. Upgrade when you need more.

Paid plans support card payments and 300+ cryptocurrencies.

Get startedView pricingAPI docs