Guide

How Polymarket crypto markets settle

Every Polymarket market resolves to a binary outcome: Up or Down. This guide covers how resolution works, the role of Chainlink price feeds, and what happens to the order book when a market settles.

What this guide covers

Binary outcomes: each market resolves to Up or Down
Chainlink price feeds provide the reference price at resolution
Settlement occurs at the market predetermined resolution timestamp
Resolved markets remain queryable with the winning outcome on every row

How markets resolve

Each Polymarket crypto market has a predetermined resolution timestamp embedded in its slug (e.g., btc-updown-5m-1787486400 resolves at Unix 1787486400).

The outcome is binary: the cryptocurrency price is either Up (above the opening price) or Down (below it). The outcome token that corresponds to the correct direction pays out $1.

Resolution is deterministic: there is no ambiguity or human judgment. The oracle reads the reference price, compares it to the opening price, and determines the outcome.

Once resolved, the market is permanently settled. Orders can no longer be filled, and outstanding positions are settled at the outcome value ($1 or $0).

Chainlink price feeds

Polymarket uses Chainlink decentralized oracle networks to provide tamper-resistant price feeds. The oracle network aggregates prices from multiple independent data sources.

The reference price is used at the resolution timestamp to determine whether the market resolves Up or Down. The oracle is designed to be resistant to manipulation.

Chainlink feeds are widely used in DeFi for price feeds on lending protocols, DEXs, and derivatives. Polymarket use of Chainlink adds credibility to the resolution process.

The oracle price is separate from the Polymarket order book price. The order book reflects traders expectations; the oracle price is the ground truth used for settlement.

Settlement timeline

Before resolution: traders can buy and sell outcome tokens freely. The order book is active, and prices reflect the market collective assessment.

At resolution: the oracle publishes the reference price. The outcome is determined instantly. The order book stops accepting new orders. Existing orders are cancelled.

After resolution: the market is settled. Winning positions pay out $1; losing positions pay out $0. The market remains queryable via the API.

The settlement process is automatic and occurs within seconds of the resolution timestamp. There is no manual intervention or waiting period.

What happens to the order book at resolution

In the final seconds before resolution, market makers typically widen their spreads and reduce their quotes. This is rational behavior because the risk of adverse selection is highest.

At the exact moment of resolution, all outstanding orders are cancelled. The order book freezes at its last state. This snapshot is preserved in the PolyOrderbooks database.

After resolution, the API continues to return data for the market. Every row in the books, prices, and metrics endpoints reflects the winning outcome.

For backtesting, resolved markets are especially valuable. You know the outcome, so you can evaluate whether a trading strategy would have been correct.

Code examples

import requests

BASE = "https://api.polyorderbooks.com/v1"
HEADERS = {"X-API-Key": "your-key"}

slug = "btc-updown-5m-1787486400"
books = requests.get(
    f"{BASE}/markets/{slug}/books",
    headers=HEADERS,
    params={"resolution": "1s"},
).json()

for snap in books[-10:]:
    bb = snap["bids"][0]["price"] if snap["bids"] else None
    ba = snap["asks"][0]["price"] if snap["asks"] else None
    print(f"t={snap['timestamp']} bid={bb} ask={ba}")

Free tier

The Starter plan is free, includes order books, prices, and metrics at 1-second resolution, with 3 days of history, 60 requests/min, 1,000/day, 1 free AI backtest, and 3 strategy backtests. No credit card required.

Paid data windows from $19/mo extend history to 30–120 days at higher throughput. Backtest AI add-on is +$19/mo or standalone at $29/mo.

FAQ

What determines the outcome of a market?

A Chainlink oracle reads the cryptocurrency price at the resolution timestamp and compares it to the opening price. If the price is higher, the market resolves Up.

Can the outcome be challenged?

No. The oracle price is final. Chainlink decentralized network is designed to produce a single, tamper-resistant price that cannot be disputed.

What happens to my orders at resolution?

All outstanding orders are cancelled instantly at the resolution timestamp. Your positions are settled at $1 (winning) or $0 (losing).

Can I still query resolved market data?

Yes. Resolved markets remain fully queryable via the API. Every row reflects the winning outcome.