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Hierarchy

Bayse uses a three-level hierarchy: Event → Market → Outcome
  • An event is the top-level container. It represents a real-world question or topic — for example, “NBA Finals 2025” or “Will it rain in Lagos tomorrow?”.
  • A market is a tradeable question within an event. Each market has exactly two outcomes (e.g. YES/NO, or two named options). Prices for the two outcomes always sum to approximately 1.00.
  • An outcome is one side of a market that you can buy or sell shares in. Each outcome has a unique UUID (outcomeId) that you use when placing orders or getting quotes.

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Events

Events group one or more related markets together. Every event has a type that determines how its markets relate to each other. Key fields:
  • title — the headline question or topic.
  • type — single, combined, or grouped (see Event types).
  • category — sports, politics, crypto, entertainment, etc.
  • status — open, closed, resolved, cancelled, paused, or draft.
  • engine — AMM or CLOB (see Market engines).
  • closingDate — when trading closes.
  • resolutionDate — when the outcome is determined.

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Markets and outcomes

Each market is a binary question with two outcomes. You trade by buying or selling shares in one of the outcomes. Key fields:
  • title — the specific question (e.g. “Will Lakers win?”).
  • outcome1Id / outcome2Id — UUIDs that uniquely identify each outcome.
  • outcome1Label / outcome2Label — labels for each side (e.g. “YES” / “NO”).
  • outcome1Price / outcome2Price — current probability prices (0.00–1.00).
  • rules — resolution criteria for this market.
  • status — same set as events.
The outcomeId is the canonical way to reference an outcome. When you fetch a market, note the outcome1Id and outcome2Id — you’ll use one of these when placing orders or requesting quotes.

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Event types

One event, one market, two outcomes. The event title and market title are typically the same.
Multiple mutually exclusive markets under one event. Only one market can resolve YES — when one wins, the others automatically resolve NO.
Multiple independent markets under one event. Each market is resolved on its own — multiple markets can resolve YES.

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Finding markets

Use the keyword query parameter on the List events endpoint to search for events by title:
You can also filter by category, status, trending, and more. See the List events reference for all available filters.