API Reference

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Base URL

https://api.entityml.com/api/v1

• GET /polymarket/market/data, GET /polymarket/market/data/range, GET /polymarket/market/orderbook-summary, GET /polymarket/market/list, and GET /polymarket/market/date-range for Polymarket
• GET /kalshi/market/data, GET /kalshi/market/data/range, GET /kalshi/market/orderbook-summary, GET /kalshi/market/list, and GET /kalshi/market/date-range for Kalshi
• GET /lookup/slug for resolving a Polymarket slug into one or more condition IDs
• /keys, /subscriptions, /usage, /user/{user_id}/requests/*, and /stats/* for key management, billing, and usage analytics
• GET /health for an unauthenticated service health check
• GET /monitoring/status for infrastructure status used by the public status page

• GET /market/data as an alias of GET /polymarket/market/data
• GET /market/data/range as an alias of GET /polymarket/market/data/range
• GET /market/orderbook-summary as an alias of GET /polymarket/market/orderbook-summary
• GET /polymarket/lookup/slug as an alias of GET /lookup/slug

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Preferred clients

python3 -m pip install --upgrade entityml

entityml health

brew install python
python3 -m pip install --upgrade entityml

python3 -m pip install --upgrade "git+https://github.com/anaygupta2004/entityml.git"

curl -L https://github.com/anaygupta2004/entityml/archive/refs/heads/main.tar.gz -o entityml.tar.gz
tar -xzf entityml.tar.gz
python3 -m pip install ./entityml-main

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Authentication

Authorization: Bearer YOUR_API_KEY

• GET /health does not require authentication
• GET /lookup/slug does not require authentication
• API key management endpoints under /keys do not use Bearer auth; they use the documented user_id and key_id parameters instead

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Request format

• All requests use standard query parameters or path parameters.
• All responses return JSON.
• Dates are formatted as YYYY-MM-DD and interpreted in UTC.
• Polymarket condition_id values are accepted with or without the 0x prefix and are normalized in responses.
• Kalshi ticker and prefix values are normalized to uppercase.
• Range endpoints accept Unix seconds or milliseconds and use inclusive start_timestamp and end_timestamp bounds.
• Date-scoped endpoints use offset pagination and return offset, limit, total_count, and has_more.
• Range endpoints use cursor pagination and return limit, has_more, and next_cursor.
• Polymarket orderbook summaries require asset_id because each condition can contain multiple outcome token books.
• You can find Polymarket asset_id values by reading a small raw data page and collecting the unique asset_id fields.
• Orderbook summary buckets include close values plus OHLC candles for best_bid, best_ask, mid_price, and spread.
• Orderbook summary endpoints accept either a UTC date or inclusive start_timestamp / end_timestamp bounds. Choose the bucket size with resolution.

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Availability and coverage

• Orderbook data exists for a subset of markets from 2025-09-01 on Polymarket and 2026-02-17 for Kalshi, but coverage is not continuous.
• Broad Polymarket crypto-related market coverage begins on 2026-02-04. Broad Kalshi crypto-related market coverage begins on 2026-02-25.
• Broad all-market capture begins on 2026-04-02 for Polymarket and 2026-03-31 for Kalshi, with known Kalshi parser and May 2026 storage-gap exceptions.
• GET /polymarket/market/date-range tells you which Polymarket UTC dates are present for a condition ID.
• GET /kalshi/market/date-range tells you which Kalshi UTC dates are present for a ticker.
• GET /polymarket/market/data currently rejects dates earlier than 2026-02-08, even if older backfilled Polymarket dates exist in storage for some markets.
• See Data Quality for the Kalshi March 31-April 24 parser issue, the Kalshi May 4-May 11 storage ingestion gap, and the Polymarket April gap notes.

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