Polymarket — Prediction Market Data
Query prediction market data from Polymarket using their public REST APIs.
All endpoints are read-only and require zero authentication.
See references/api-endpoints.md for the full endpoint reference with curl examples.
When to Use
- User asks about prediction markets, betting odds, or event probabilities
- User wants to know "what are the odds of X happening?"
- User asks about Polymarket specifically
- User wants market prices, orderbook data, or price history
- User asks to monitor or track prediction market movements
Key Concepts
- Events contain one or more Markets (1:many relationship)
- Markets are binary outcomes with Yes/No prices between 0.00 and 1.00
- Prices ARE probabilities: price 0.65 means the market thinks 65% likely
outcomePrices field: JSON-encoded array like ["0.80", "0.20"]clobTokenIds field: JSON-encoded array of two token IDs [Yes, No] for price/book queriesconditionId field: hex string used for price history queries- Volume is in USDC (US dollars)
Three Public APIs
- Gamma API at
gamma-api.polymarket.com — Discovery, search, browsing
- CLOB API at
clob.polymarket.com — Real-time prices, orderbooks, history
- Data API at
data-api.polymarket.com — Trades, open interest
Typical Workflow
When a user asks about prediction market odds:
- Search using the Gamma API public-search endpoint with their query
- Parse the response — extract events and their nested markets
- Present market question, current prices as percentages, and volume
- Deep dive if asked — use clobTokenIds for orderbook, conditionId for history
Presenting Results
Format prices as percentages for readability:
- outcomePrices
["0.652", "0.348"] becomes "Yes: 65.2%, No: 34.8%"
- Always show the market question and probability
- Include volume when available
Example: "Will X happen?" — 65.2% Yes ($1.2M volume)
Parsing Double-Encoded Fields
The Gamma API returns outcomePrices, outcomes, and clobTokenIds as JSON strings
inside JSON responses (double-encoded). When processing with Python, parse them with
json.loads(market['outcomePrices']) to get the actual array.
Rate Limits
Generous — unlikely to hit for normal usage:
- Gamma: 4,000 requests per 10 seconds (general)
- CLOB: 9,000 requests per 10 seconds (general)
- Data: 1,000 requests per 10 seconds (general)
Limitations
- This skill is read-only — it does not support placing trades
- Trading requires wallet-based crypto authentication (EIP-712 signatures)
- Some new markets may have empty price history
- Geographic restrictions apply to trading but read-only data is globally accessible
1---2name: polymarket3description: Query Polymarket prediction market data — search markets, get prices, orderbooks, and price history. Read-only via public REST APIs, no API key needed.4---56# Polymarket — Prediction Market Data78Query prediction market data from Polymarket using their public REST APIs.9All endpoints are read-only and require zero authentication.1011See `references/api-endpoints.md` for the full endpoint reference with curl examples.1213## When to Use1415- User asks about prediction markets, betting odds, or event probabilities16- User wants to know "what are the odds of X happening?"17- User asks about Polymarket specifically18- User wants market prices, orderbook data, or price history19- User asks to monitor or track prediction market movements2021## Key Concepts2223- **Events** contain one or more **Markets** (1:many relationship)24- **Markets** are binary outcomes with Yes/No prices between 0.00 and 1.0025- Prices ARE probabilities: price 0.65 means the market thinks 65% likely26- `outcomePrices` field: JSON-encoded array like `["0.80", "0.20"]`27- `clobTokenIds` field: JSON-encoded array of two token IDs [Yes, No] for price/book queries28- `conditionId` field: hex string used for price history queries29- Volume is in USDC (US dollars)3031## Three Public APIs32331. **Gamma API** at `gamma-api.polymarket.com` — Discovery, search, browsing342. **CLOB API** at `clob.polymarket.com` — Real-time prices, orderbooks, history353. **Data API** at `data-api.polymarket.com` — Trades, open interest3637## Typical Workflow3839When a user asks about prediction market odds:40411. **Search** using the Gamma API public-search endpoint with their query422. **Parse** the response — extract events and their nested markets433. **Present** market question, current prices as percentages, and volume444. **Deep dive** if asked — use clobTokenIds for orderbook, conditionId for history4546## Presenting Results4748Format prices as percentages for readability:49- outcomePrices `["0.652", "0.348"]` becomes "Yes: 65.2%, No: 34.8%"50- Always show the market question and probability51- Include volume when available5253Example: `"Will X happen?" — 65.2% Yes ($1.2M volume)`5455## Parsing Double-Encoded Fields5657The Gamma API returns `outcomePrices`, `outcomes`, and `clobTokenIds` as JSON strings58inside JSON responses (double-encoded). When processing with Python, parse them with59`json.loads(market['outcomePrices'])` to get the actual array.6061## Rate Limits6263Generous — unlikely to hit for normal usage:64- Gamma: 4,000 requests per 10 seconds (general)65- CLOB: 9,000 requests per 10 seconds (general)66- Data: 1,000 requests per 10 seconds (general)6768## Limitations6970- This skill is read-only — it does not support placing trades71- Trading requires wallet-based crypto authentication (EIP-712 signatures)72- Some new markets may have empty price history73- Geographic restrictions apply to trading but read-only data is globally accessible
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