Response fields

The full field dictionary for the event and entity responses. Each endpoint returns these objects; this page defines every field once.

Event

The object returned by Get Oddpool ID by ticker, Get a matched event, and each item in List matched events.

string

The event id (OPI-XXXXXXXX).

string

Event display title.

string | null

Free-text category, sourced from Kalshi (e.g. Sports). Not a closed enum; may be null for uncategorized events.

string | null

ISO 8601 timestamp of the last time the event’s canonical state was refreshed. Advances on new outcomes, settlement reclassification, and divergence re-validation, not on price or volume. Use it as the high-water mark for incremental sync via classified_since.

EventVenueListing[]

The event as each venue lists it, one entry per venue. See Event venue listing.

EventVenuePair[]

Per-venue-pair settlement classification, one entry per pair of venues that both list the event. See Event venue pair.

Outcome[]

Each named answer on the event. See Outcome.

Event venue listing

An entry in the event’s venue_listings. Names the parent event on one venue.

string

Listing id (OPL:…).

string

kalshi, polymarket, or polymarket_us.

string

The venue’s identifier for the parent event.

string | null

Raw question text from the venue at the time of mapping.

Event venue pair

An entry in the event’s venue_pairs. Fungibility is a property of a venue pair, not a scalar on the event, so an event on N venues has one entry per pair. Venues are precedence-ordered (kalshi < polymarket < polymarket_us).

string

First venue in the pair.

string

Venue A’s event id. Names the exact venue event the pair relates (needed when a canonical event spans several events on one venue; redundant in the common 1:1 case).

string

Second venue in the pair.

string

Venue B’s event id.

string | null

The settlement-rule axis: whether the two venues agree on when, by what authority, and under what timing window the event resolves.

Value	Meaning
`identical`	Same resolution anchor, same authority, gap ≤ 24 hours.
`settlement_window`	Settlement timestamps diverge by more than 24 hours, or the venues anchor on different stages of the resolution chain (e.g. election day vs. certification).
`settlement_source`	Both venues settle on the same nominal value but read it from two different named authorities (e.g. National Weather Service vs. Weather Underground).

string | null

The outcome-list correspondence axis: how much the two venues’ outcome sets line up.

Value	Meaning
`identical`	Every outcome paired 1:1 across the two venues.
`partial`	Some outcomes paired, at least one is one-sided.
`disjoint`	No outcomes are paired across the two venues.

Outcome

An entry in the event’s outcomes.

string

Outcome id (OPO:…).

string

Display label: an entity name, bucket descriptor, Yes, etc.

string

The structural type of the outcome.

Value	Shape
`binary`	Single YES/NO proposition.
`multi_class_named`	N named entity outcomes; one wins.
`range_bin`	Continuous variable bucketed into discrete intervals.
`threshold_above`	Cumulative ladder: above N / ≥ N.
`threshold_below`	Cumulative ladder: below N / ≤ N.
`point_mass`	Exact-value outcome.
`spread`	Handicap on a line.
`will_happen_by_date`	Time-bound binary with a deadline.

object

Type-specific structured parameters. Numeric kinds carry outcome_params.bucket; will_happen_by_date carries outcome_params.deadline; binary and multi_class_named are {}. See outcome_params shapes. Additional non-load-bearing keys may appear alongside bucket / deadline (unmatched_in_counterparty, residual, audit keys). Rely on bucket / deadline and ignore unknown siblings.

CanonicalEntity | null

The canonical entity this outcome refers to, or null for non-entity outcomes such as Tie or Other. See Entity.

OutcomeVenueListing[]

The tradeable side of this outcome on each venue, the ids you subscribe to. See Outcome venue listing.

OutcomeVenuePair[]

Per-venue-pair fungibility for this outcome, one entry per pair of venues that both list it. See Outcome venue pair.

outcome_params shapes

// range_bin: half-open numeric interval
"outcome_params": { "bucket": { "shape": "discrete_range",
  "lo": 0.0, "hi": 50000.0, "lo_inclusive": true, "hi_inclusive": false, "units": "count" } }

// threshold_above: cumulative ladder, open upper bound
"outcome_params": { "bucket": { "shape": "cumulative_threshold",
  "lo": 25.0, "hi": null, "lo_inclusive": false, "hi_inclusive": null, "units": "bps" } }

// threshold_below: cumulative ladder, open lower bound
"outcome_params": { "bucket": { "shape": "cumulative_below",
  "lo": null, "hi": 0.0, "lo_inclusive": null, "hi_inclusive": false, "units": "count" } }

// point_mass: exact value
"outcome_params": { "bucket": { "shape": "point_value",
  "lo": -25, "hi": -25, "lo_inclusive": true, "hi_inclusive": true, "units": "bps" } }

// spread: handicap on a line; line and side are spread-only
"outcome_params": { "bucket": { "shape": "spread", "line": 1.5, "side": "favorite",
  "lo": 1.5, "hi": null, "lo_inclusive": false, "hi_inclusive": null, "units": "pts" } }

// will_happen_by_date
"outcome_params": { "deadline": { "iso8601": "2027-01-01", "inclusive": false } }

// binary, multi_class_named: no structural params
"outcome_params": { }

Outcome venue listing

An entry in an outcome’s venue_listings, one venue’s tradeable side of the outcome.

string

Listing id (OPL:…).

string

kalshi, polymarket, or polymarket_us.

string

The venue’s native identifier for this tradeable side, the value you trade on.

Kalshi: the market ticker.
Polymarket binary YES/NO: the conditionId. Trade via the CLOB using conditionId plus the side’s token below.
Polymarket atomic-binary multi-side: conditionId#<index>. Split on # to recover the native conditionId; the side’s CLOB token is below.
Polymarket US: <marketSlug>#<YES|NO>. Split on # to recover the order-API marketSlug and the side. Polymarket US has no CLOB tokens; orders reference the marketSlug and side directly.

string | null

The venue’s identifier for the parent event. Kalshi: event ticker. Polymarket and Polymarket US: the event slug (the human-readable id, not the numeric event id).

string | null

Polymarket CLOB token id for the YES side. null on Kalshi and Polymarket US.

string | null

Polymarket CLOB token id for the NO side. null on Kalshi and Polymarket US.

string | null

Raw question text from the venue at the time of mapping.

Outcome venue pair

An entry in an outcome’s venue_pairs, showing whether the outcome’s two venue sides are one tradeable instrument.

string

First venue in the pair.

string

Second venue in the pair.

boolean

true iff the event leg’s basis_class == identical and divergence_axes == []. When true, the two listings are one tradeable instrument (same payoff, same nominal value, same authority, same timing) and can be treated as one for quoting, hedging, and risk. The one-glance answer.

string[]

Subset of {timing, source, condition_scope}: how the two listings settle differently when they are the same nominal outcome. Empty means no axis-level divergence on this leg.

Axis	Meaning
`timing`	Same outcome, fixed at different moments: one on the event itself, the other on a later administrative step (certification, swearing-in). The eventual answer matches, but early-resolution and payout timing can differ.
`source`	Same value, read from two different named authorities (e.g. National Weather Service vs. Weather Underground). Agree in the modal case, can diverge on edge measurements.
`condition_scope`	The most common axis, and usually just the venues’ standard cancellation/postponement policy. Still the same outcome: it settles identically in the normal case and differs only on rare edge cases (game cancelled or postponed past a window, a tie), where one venue pays the last-traded price and the other resolves No or 50-50. Common on sports and entertainment.

For how condition_scope affects the fungible filter, and when to treat it as tradeable with allow, see Fungibility and cancellation risk.

string | null

One-sentence explanation of the specific case, populated when divergence_axes is non-empty.

Entity

The object returned by the entity endpoints, and nested under each outcome.entity.

string

Entity id (OPE:{KIND}:{slug}).

string

One of person, team, political_party, cultural_work, geographic_region, organization, event_occurrence.

string

The canonical display name.

string[]

Alternate names observed on venues and curated alternates.

string | null

Wikidata Q-ID, a stable cross-reference to FEC, bioguide, LEI, sports-reference, MusicBrainz, and other identifier systems. null for auto-minted entities.

object

Kind-specific structured fields. Shape varies by kind. For example, Person: country, party_qid, person_kind; Team: league, sport, city, parent_qid; Organization: country, tickers. Values that reference other entities are Wikidata Q-IDs (country: "Q30"). Treat as open JSON: use the keys you recognize, ignore the rest.

string

wikidata when the record is sourced from Wikidata; llm_auto when auto-minted from venue text because no Wikidata match was available.

string | null

ISO 8601 timestamp of the most recent Wikidata sync, where applicable.

Reference Data API

Matched events

Entities

Event

Event venue listing

Event venue pair

Outcome

outcome_params shapes

Outcome venue listing

Outcome venue pair

Entity

​Event

​Event venue listing

​Event venue pair

​Outcome

​outcome_params shapes

​Outcome venue listing

​Outcome venue pair

​Entity

Event

Event venue listing

Event venue pair

Outcome

outcome_params shapes

Outcome venue listing

Outcome venue pair

Entity