Polymarket API Pricing: What It Costs and What It Doesn't

Yes, and it is worth being precise about why, because “free” gets used loosely. Polymarket does not operate a commercial data business. There is no pricing page for the API, no metered plan, and no key to purchase. The read paths are open:

• No API key. Public market-data endpoints take no credential at all.
• No account. You do not need to register to read markets or books.
• No wallet. A connected wallet is required to trade, not to read.

Trading is where authentication appears, and it is still not a purchase: you derive API credentials by signing a message with your Polygon wallet. That is an identity step, not a subscription. See Polymarket's API introduction for the auth model.

The practical consequence: a typical workflow starts on Gamma to resolve a market slug into CLOB token IDs, then moves to the CLOB API for book and price data. Budget your request volume per surface, not globally.

Since access is free, rate limits — not price — are what bound a data pipeline. Polymarket enforces per-endpoint quotas at the edge, with separate budgets for Gamma, the CLOB, and the Data API. Exceed them and you get throttled, then HTTP 429s; sustained overshoot can lead to a temporary block.

Quotas differ per surface and have been revised more than once, so treat Polymarket's official rate limits page as the only authority. For representative figures with the endpoints broken out, see the rate limits section of our Polymarket API guide.

Three habits that keep you inside the limits:

• Batch where a batch endpoint exists — prefer one multi-token request over a loop of single-token calls.
• Cache market metadata. Slugs, token IDs, and outcomes rarely change; re-resolving them on every request wastes your Gamma budget.
• Use the WebSocket market channel for live book changes instead of polling GET /book. Streaming is what it is for.

People searching for Polymarket's fees are usually asking about trading, not data. These are unrelated: the API costs nothing regardless of what a market charges to trade.

Fees are set per market rather than platform-wide. Some markets charge taker fees; others are fee-free, and the schedule has been revised over time. Because it varies by market and by date, check Polymarket's fee documentation for the market you actually care about rather than trusting a single headline percentage.

Separately, Polymarket settles on Polygon, so deposits, withdrawals, and on-chain actions carry network gas costs. Again — not an API charge.

Price history is genuinely free, including old resolved markets

A common claim is that /prices-history stops serving fine granularity once a market resolves. That is not what the endpoint does. Bound the request with startTs and endTs and 1-minute buckets come back normally:

The empty responses come from interval=max, not from resolution. An unbounded request for a long-lived market at fine granularity returns nothing; the same market over a bounded window returns a full series. This was reported as py-clob-client issue #216, which is closed — that client was archived read-only in May 2026. If you hit it, pass a time range instead of interval=max.

One minute is the floor

fidelity is expressed in minutes, so a minute is the finest bucket on offer. Passing fidelity=0 returns the raw retained points rather than a finer grid: on a five-minute market that was 10 points spaced 41 to 75 seconds apart, median 62. Fine for most analysis. Not a second-level series.

Order book depth is not archived at all

This is the real gap, and unlike the others it has no workaround. The GET /book endpoint returns the current state. There is no documented route to the ladder as it stood at a past timestamp, at any granularity, at any price.

Depth is forward-only. A price series tells you where the market traded; it cannot tell you what size rested at each level, what a 500-share order would have cost to fill, or how the book thinned before resolution. If nobody recorded the ladders while the market was live, that detail does not exist anywhere — not in the API, not in an archive, not for purchase.

So when does free stop being enough?

To be clear about when you do not need to pay anyone: live prices, current order books, market discovery, trade history, minute-resolution price history on resolved markets, and order placement are all free, documented, and sufficient. Most projects never need more.

You need an archive when your question is about execution rather than price — slippage against real depth, fill probability, spread dynamics, or liquidity before a resolution. Those questions need the ladder, and the ladder has to have been captured at the time.

That is what PolyOrderbooks records: a queryable REST archive of Polymarket crypto order books captured live at 1-second resolution, with resolved markets kept alongside their winning outcome. You can download a free 1-second L2 sample and inspect the schema before deciding anything, or read the API quickstart.