How to Get Polymarket Historical Data: The Complete Guide

Whether you're backtesting a strategy, training a model, or writing a research paper, at some point you need historical Polymarket data — and you'll quickly discover that most of it isn't sitting behind a convenient download button. This guide covers every practical option, what each one actually contains, and where the gaps are.

What "historical data" means on Polymarket

Polymarket data comes in layers, and each layer has a different availability story:

The deeper you go down that table, the more valuable the data is for serious work — and the harder it is to get.

Option 1: Polymarket's public APIs

Polymarket's Gamma API and CLOB API are free and public. They're the right tool for:

• Market catalogs — every market, its outcomes, volume, and resolution
• Price history — sampled time series per market via the prices-history endpoint
• The current orderbook — live depth for any market, right now

The key limitation: the CLOB API serves the present, not the past. Price history is sampled (not tick-accurate), and the orderbook endpoint has no time dimension at all. Once an order is cancelled or filled, it's gone. If your strategy depends on where the book was — queue position, depth at a level, spread dynamics — the public API cannot tell you.

Option 2: Index the Polygon blockchain yourself

Every Polymarket trade settles on Polygon through the CTF Exchange contracts, so in principle the full trade history is public. In practice, reconstructing it means:

1. Running or paying for a Polygon archive node
2. Decoding OrderFilled events (and negative-risk variants) from raw logs
3. Mapping token IDs to markets and outcomes via the CTF contracts
4. Handling proxy wallets, splits, merges, and redemptions to get true positions
5. Backfilling from 2020 and keeping the pipeline running forever

We wrote a whole post on why this is harder than it looks — see The Hidden Complexity of Indexing Polymarket. It's a multi-month engineering project, and it still only gets you trades, not orderbooks: the book lives on Polymarket's off-chain CLOB, so no amount of chain indexing recovers it.

Option 3: A prediction market data provider

This is what Predexon exists for:

• Complete trade and price history since 2020 — indexed from Polygon, accurate to the block, queryable over REST in seconds
• Tick-level orderbook history — every placement, update, cancel, and fill, at full depth, captured continuously by our always-on recorder since January 2026. Quote any market and date range for free, then download compressed Parquet ($40/GiB). Granularities from raw ticks to 1h. This dataset doesn't exist anywhere else — it has to be captured live, and we're capturing it.
• Wallet analytics — positions, PnL, and leaderboards for every address, pre-computed

The Polymarket data API has a free tier for REST access, and new accounts get $50 in free data credits for orderbook history downloads.

Which option should you use?

Building a dashboard or bot that needs current markets and prices? Polymarket's public APIs are free and fine.

Need complete trade history and don't want to run an indexer? A data provider will save you months.

Backtesting execution, market-making, or anything microstructure-sensitive? You need historical orderbooks, and there is exactly one way to get them: from someone who recorded the book as it happened. That's tick-level orderbook history.

Doing academic research? Parquet downloads with millisecond timestamps drop straight into pandas, Polars, or DuckDB — and you can cite exact coverage windows.

Getting started

# Markets
curl "https://api.predexon.com/v2/polymarket/markets?search=fed&status=open" \
  -H "x-api-key: <your-api-key>"

# Quote an orderbook history slice — free
curl "https://api.predexon.com/v2/data/ticks/quote?venue=polymarket&granularity=raw&from=2024-10-01&to=2024-11-06" \
  -H "x-api-key: <your-api-key>"

Get an API key at dashboard.predexon.com — free tier, no credit card.