Event discovery
Categories, dates, entities, questions, related markets, and searchable metadata.
PREDICTION API
Prediction Markets Trader API
Independent guidance for building event-market research, data, dashboard, and supervised trading applications.
Developer overview
What this API category covers
Prediction-market integrations need more than a price feed. They must preserve the relationship between events, questions, outcomes, tradable contracts, governing rules, market states, and settlement. A price can be interpreted as probability-like information, but it remains a market value influenced by liquidity, spread, fees, and structure.
Do not choose an interface from a marketing checklist alone. Verify schemas, units, timestamps, permissions, failure behavior, testing conditions, and data-use terms for the exact product and account. A production integration should be able to recover authoritative state after a disconnect without guessing.
Capability map
Core integration responsibilities
Use these responsibilities to define architecture, acceptance tests, and provider evidence.
Contract rules
Resolution source, cutoff, conditions, clarifications, and void or dispute handling.
Outcome pricing
Bid, ask, last trade, midpoint, quantity, spread, timestamp, and liquidity context.
Order books
Snapshots, updates, sequences, price increments, contract quantities, and recovery.
Market lifecycle
Scheduled, open, paused, closed, resolved, disputed, voided, and settled states.
Portfolio workflows
Orders, fills, positions, fees, payout exposure, settlement, and correlated risk.
Implementation
Production checklist
- Map events, markets, contracts, and outcomes.
- Store exact resolution rules and changes.
- Label bid, ask, last, and midpoint distinctly.
- Preserve raw numeric units and use exact decimals.
- Handle every market state, not just open and closed.
- Rebuild order-book state after sequence gaps.
- Verify jurisdiction, eligibility, and data rights.
- Review Polymarket and Kalshi pages independently.
Conceptual adapter
const adapter = {
instruments: "provider identifiers",
timestamps: "UTC + source context",
numbers: "exact decimals",
streaming: "snapshot + recovery",
orders: "idempotent state machine",
credentials: "server-side only",
evidence: "docs + tests + logs"
};
Related research
Continue evaluating
Polymarket Prediction Trader API
Research questions for markets, outcomes, rules, books, settlement, and access.
Open overview →Kalshi Prediction Trader API
Independent evaluation of event data, price units, order lifecycle, rules, and state.
Open overview →FAQ
Prediction Markets Trader API questions
What is a Prediction Markets Trader API?
It is an interface that may expose event questions, tradable outcomes, prices, order books, orders, positions, and settlement information.
Is the displayed price a guaranteed probability?
No. It is a market price affected by liquidity, spread, fees, and market structure. Applications should identify which price measure they display.
Why are resolution rules important?
The title may not fully define the settlement condition. Rules identify the source, timing, exceptions, and process that determine the outcome.
Can access vary by location?
Yes. Platform eligibility, products, and legal restrictions may depend on jurisdiction. Verify current requirements directly with the platform and qualified advisers.