What is a market on Polymarket?

A market is the fundamental tradable unit on Polymarket. It represents a single binary question with Yes/No outcomes. Each market has a Condition ID (CTF), a Question ID (for resolution), and two Token IDs (ERC1155)—one for Yes, one for No. You trade these tokens on the CLOB order book.

What is an event on Polymarket?

An event is a container that groups one or more related markets. A single-market event has one market (e.g. Will Bitcoin reach $100k?). A multi-market event has several mutually exclusive markets (e.g. Who will win the election? with Trump, Biden, Harris, Other). Events provide structure; the tradable unit is always the market.

What is a Condition ID and Token ID on Polymarket?

The Condition ID uniquely identifies the market in the Conditional Token Framework (CTF) smart contracts. Token IDs are the ERC1155 token identifiers for the Yes and No outcome tokens—you trade these on the CLOB and hold them as positions. The Question ID is a hash of the market question used when the market resolves.

How do I fetch a Polymarket event or market by slug?

Every event (and in practice each market) has a unique slug in the URL, e.g. polymarket.com/event/fed-decision-in-october. You can fetch event data from the Gamma API: GET https://gamma-api.polymarket.com/events?slug=your-slug

Polymarket Markets & Events: Understanding the Fundamental Building Blocks

Every prediction on Polymarket is structured around two core concepts: markets and events. A market is the fundamental tradable unit—one binary question with Yes/No outcomes. An event is a container that groups one or more markets together. Understanding how they relate is essential for building on the platform or trading with an edge. This guide summarizes the structure from Polymarket’s official docs and how it ties to prices, tokens, and resolution.

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Markets: The Tradable Unit

A market is a single binary question with exactly two outcomes: Yes and No. Each market has three key identifiers (from Polymarket’s Markets & Events docs):

Identifier	Description
Condition ID	Unique identifier for the market’s condition in the CTF (Conditional Token Framework) contracts. Used onchain and by the CLOB to refer to this market.
Question ID	Hash of the market question. Used at resolution so the oracle knows which question it is answering.
Token IDs	Two ERC1155 token IDs used for trading on the CLOB—one for Yes, one for No. These are the actual instruments you buy, sell, and hold as positions.

Markets can only be traded via the CLOB if enableOrderBook is true. Some markets exist onchain but are not available for order book trading.

Example market

"Will Bitcoin reach $150,000 by December 2026?"

Yes token — Redeemable for $1 if Bitcoin reaches $150k.
No token — Redeemable for $1 if it does not.

Events: Containers for One or More Markets

An event is a container that holds one or more markets. It provides organizational structure and enables multi-outcome predictions (e.g. "Who will win?" with several candidates).

Single-market events

One event, one market: the event and market are effectively the same.

Event: Will Bitcoin reach $100,000 by December 2024?
└── Market: Will Bitcoin reach $100,000 by December 2024? (Yes/No)

Multi-market events

One event, multiple markets: several mutually exclusive binary questions under one theme.

Event: Who will win the 2024 Presidential Election?
├── Market: Donald Trump? (Yes/No)
├── Market: Joe Biden? (Yes/No)
├── Market: Kamala Harris? (Yes/No)
└── Market: Other? (Yes/No)

Each market is still binary (Yes/No). The event groups them so you can trade "Trump vs Biden vs Harris vs Other" in one place. The fundamental unit for trading and resolution is always the market.

How This Connects to Tokens and the CLOB

From Polymarket’s Positions & Tokens docs: each market has exactly two outcome tokens (Yes and No), implemented as ERC1155 tokens using the Gnosis Conditional Token Framework (CTF). Every Yes/No pair is backed by $1 USDC.e collateral in the CTF—so 1 Yes + 1 No always equals $1 of value at resolution. You trade these tokens on the CLOB (Central Limit Order Book); the Token IDs from the market are what the CLOB and APIs use. Your position is your balance of those tokens. So: Market → Condition ID + Question ID + 2 Token IDs → those tokens are what you hold and trade. For how prices are set (bid/ask, probability), see Prices & Orderbook and our how prediction market prices relate to probability.

Identifying Markets and Events: Slugs and APIs

Every event (and in practice each market) has a unique slug used in URLs and APIs. Example: https://polymarket.com/event/fed-decision-in-october → slug = fed-decision-in-october. You can fetch event data from the Gamma API:

curl "https://gamma-api.polymarket.com/events?slug=fed-decision-in-october"

Polymarket’s data is split across three APIs: Gamma API (events, markets, discovery—list events, list markets, search), CLOB API (prices, order books, order placement, keyed by token ID), and Data API (positions, trades, activity, leaderboard per user or market). Events and markets metadata come from Gamma; trading and order book are keyed by the market’s token IDs on the CLOB.

Resolution: How Markets End

When the real-world outcome is known, the market is resolved. Winning outcome tokens (Yes or No) can be redeemed for $1 each; losing tokens are worth $0. Resolution uses the UMA Optimistic Oracle: someone proposes an outcome, others can dispute, and after the challenge period the result is final. The Question ID ties the oracle answer to the correct market. So the market (and its Question ID) is the unit that gets one resolved outcome; events don’t resolve—each market inside an event resolves independently. For the full flow, see Polymarket’s Resolution docs and our how Polymarket’s oracle and resolution work.

Sports Markets

For sports markets, outstanding limit orders are automatically cancelled when the game begins (the order book is cleared at the official start time). Game start times can change—if a game starts earlier than scheduled, orders might not be cleared in time, so monitor orders closely around start times.

Summary

Concept	What it is
Event	Container: one topic, one or more markets (e.g. 2024 election, Fed decision).
Market	One binary question (Yes/No) plus Condition ID, Question ID, and two Token IDs.
Condition ID	Unique id for the market in the CTF contracts.
Question ID	Hash of the question; used at resolution.
Token IDs	ERC1155 ids for Yes and No; these are what you trade on the CLOB and hold.
Slug	Human-readable id in URLs/APIs (e.g. fed-decision-in-october).

Markets and events are the fundamental building blocks: events organize markets; each market is the single tradable unit (one binary question, two tokens, one resolution). Everything else—order book, positions, resolution—is defined per market. To find top Polymarket wallets and copy their positions, use the HolyPoly leaderboard.