Sports Schema - Polymarket US Documentation

This page documents the strongly-typed fields on the instrument that should be used to identify a sports market. Do not parse the instrument symbol or slug — symbol formats are not part of the public contract and may change. Always identify markets using the fields below.

Section 1: Common Identifying Fields

The following fields appear on every sports instrument. Together they uniquely describe the sport, league, event, period, market type, and handicap of a contract.

Field Reference

Field	Location	Type	Description
`event_start_time`	`metadata`	Timestamp (UTC)	Scheduled start time of the underlying event. Updated in place when a game is rescheduled.
`event_subcategory`	`metadata`	Enum	The sport. Values: `BASKETBALL`, `FOOTBALL`, `BASEBALL`, `SOCCER`, etc.
`outcome_type`	`metadata`	Enum	The market structure. Still present on every instrument, but do not use it for market mapping — use `market_sport_type` instead. See the enum list below.
`market_sport_type`	`metadata`	Enum	The fully-qualified market type, including sport, participant scope, and game period. Always populated on every sports instrument, including full-game spreads, totals, and outright winners. See the enum list below.
`outcome_strike`	`metadata`	String (numeric)	The handicap or threshold for the market. Unsigned magnitude — the side the contract pays out on is encoded by `long_participant_id`. For a Cleveland +3.5 spread, this is `"3.5"`. For an over/under total of 4.5, this is `"4.5"`. Empty/`"0.0"` for moneylines.
`long_participant_id`	`metadata`	String	Globally unique ID of the side the contract pays out on (e.g. `mlb-cle`). Only populated on individual game markets (moneylines, spreads, totals, props) — do not rely on it for futures.

`outcome_type` Enum

The market structure of a sports instrument.

Value	Meaning
`moneyline`	Win/lose market (no handicap).
`spreads`	Point/goal/run handicap market.
`totals`	Over/under combined-score market.
`props`	Player or team prop.
`futures`	Season-long or event-long futures market.
`drawable_outcome`	Exclusive group market that admits a draw (e.g. 3-way soccer outcome).

`market_sport_type` Enum

The fully-qualified market type, including sport, participant scope, and game period. This field is populated on every sports instrument — full-game spreads, totals, and outright winners included — so you can treat it as the single source of truth for any market. You no longer need to check outcome_type to map a market; market_sport_type alone is sufficient.

Value	Sport	Scope	Period	Type
`baseball_player_home_runs`	Baseball	Player	Full game	Home runs prop
`baseball_player_strikeouts`	Baseball	Player	Full game	Strikeouts prop
`baseball_player_hits`	Baseball	Player	Full game	Hits prop
`baseball_player_total_bases`	Baseball	Player	Full game	Total bases prop
`baseball_player_hits_runs_rbis`	Baseball	Player	Full game	Hits + runs + RBIs prop
`baseball_player_outs`	Baseball	Player	Full game	Pitcher outs prop
`baseball_player_earned_runs_allowed`	Baseball	Player	Full game	Earned runs allowed prop
`baseball_player_hits_allowed`	Baseball	Player	Full game	Hits allowed prop
`baseball_player_walks_allowed`	Baseball	Player	Full game	Walks allowed prop
`baseball_team_first_inning_run`	Baseball	Team	1st inning	Run scored
`baseball_game_extra_innings`	Baseball	Game	Full game	Extra innings yes/no
`baseball_team_first_five_winner`	Baseball	Team	First 5 innings	Prop
`baseball_team_first_five_spread`	Baseball	Team	First 5 innings	Spread
`baseball_team_first_five_total`	Baseball	Team	First 5 innings	Total
`baseball_team_full_game_winner`	Baseball	Team	Full game	Moneyline
`baseball_team_full_game_spread`	Baseball	Team	Full game	Spread
`baseball_team_full_game_total`	Baseball	Team	Full game	Total
`basketball_player_points`	Basketball	Player	Full game	Points prop
`basketball_player_assists`	Basketball	Player	Full game	Assists prop
`basketball_player_rebounds`	Basketball	Player	Full game	Rebounds prop
`basketball_player_threes`	Basketball	Player	Full game	Three-pointers prop
`basketball_player_steals`	Basketball	Player	Full game	Steals prop
`basketball_player_blocks`	Basketball	Player	Full game	Blocks prop
`basketball_player_double_double`	Basketball	Player	Full game	Double-double yes/no
`basketball_player_triple_double`	Basketball	Player	Full game	Triple-double yes/no
`basketball_team_first_half_winner`	Basketball	Team	First half	Prop
`basketball_team_first_half_spread`	Basketball	Team	First half	Spread
`basketball_team_first_half_total`	Basketball	Team	First half	Total
`basketball_team_second_half_winner`	Basketball	Team	Second half	Prop
`basketball_team_second_half_spread`	Basketball	Team	Second half	Spread
`basketball_team_second_half_total`	Basketball	Team	Second half	Total
`basketball_team_first_quarter_spread`	Basketball	Team	1st quarter	Spread
`basketball_team_first_quarter_total`	Basketball	Team	1st quarter	Total
`basketball_team_second_quarter_spread`	Basketball	Team	2nd quarter	Spread
`basketball_team_second_quarter_total`	Basketball	Team	2nd quarter	Total
`basketball_team_third_quarter_spread`	Basketball	Team	3rd quarter	Spread
`basketball_team_third_quarter_total`	Basketball	Team	3rd quarter	Total
`basketball_team_fourth_quarter_spread`	Basketball	Team	4th quarter	Spread
`basketball_team_fourth_quarter_total`	Basketball	Team	4th quarter	Total
`basketball_game_overtime`	Basketball	Game	Full game	Overtime yes/no
`basketball_team_full_game_winner`	Basketball	Team	Full game	Moneyline
`basketball_team_full_game_spread`	Basketball	Team	Full game	Spread
`basketball_team_full_game_total`	Basketball	Team	Full game	Total
`football_team_full_game_winner`	Football	Team	Full game	Moneyline
`football_team_full_game_spread`	Football	Team	Full game	Spread
`football_team_full_game_total`	Football	Team	Full game	Total
`soccer_team_full_time_winner`	Soccer	Team	Full time	Moneyline (3-way)
`soccer_team_full_game_spread`	Soccer	Team	Full game	Spread
`soccer_team_full_game_total`	Soccer	Game	Full game	Total goals across both teams (combined)
`soccer_game_btts`	Soccer	Game	Full game	Both teams to score
`soccer_game_first_team_to_score`	Soccer	Game	Full game	First team to score
`soccer_game_next_team_to_score`	Soccer	Game	Full game	Next team to score
`soccer_game_goal_in_interval`	Soccer	Game	Interval	Goal in interval
`soccer_game_exact_score`	Soccer	Game	Full game	Exact score
`soccer_game_to_advance`	Soccer	Team	Tie/match	To advance
`soccer_team_first_half_winner`	Soccer	Team	First half	Prop
`soccer_team_first_half_spread`	Soccer	Team	First half	Spread
`soccer_team_first_half_total`	Soccer	Game	First half	Total goals across both teams (combined)
`soccer_game_first_half_btts`	Soccer	Game	First half	Both teams to score, first-half goals only
`soccer_game_first_half_first_team_to_score`	Soccer	Game	First half	First team to score, first-half goals only
`soccer_game_total_corners`	Soccer	Game	Full game	Total corners across both teams (combined)
`soccer_team_second_half_winner`	Soccer	Team	Second half	Prop
`soccer_team_second_half_spread`	Soccer	Team	Second half	Spread
`soccer_team_second_half_total`	Soccer	Game	Second half	Total goals across both teams (combined)
`soccer_game_second_half_btts`	Soccer	Game	Second half	Both teams to score, second-half goals only
`soccer_game_second_half_first_team_to_score`	Soccer	Game	Second half	First team to score, second-half goals only
`soccer_team_total_goals`	Soccer	Team	Full game	Total goals for a single team
`soccer_team_total_goals_first_half`	Soccer	Team	First half	Total goals for a single team
`soccer_game_total_goals_odd_even`	Soccer	Game	Full game	Total goals odd/even
`soccer_game_first_half_exact_score`	Soccer	Game	First half	Exact score
`soccer_player_goals`	Soccer	Player	Full game	Goals prop
`soccer_player_assists`	Soccer	Player	Full game	Assists prop
`soccer_player_shots`	Soccer	Player	Full game	Shots prop
`soccer_player_shots_on_target`	Soccer	Player	Full game	Shots on target prop
`soccer_player_goalkeeper_saves`	Soccer	Player	Full game	Goalkeeper saves prop
`soccer_player_goals_plus_assists`	Soccer	Player	Full game	Goals + assists prop
`soccer_team_total_corners`	Soccer	Team	Full game	Total corners for a single team
`soccer_game_corners_odd_even`	Soccer	Game	Full game	Corners odd/even
`soccer_game_goes_to_extra_time`	Soccer	Game	Full time	Will the match go to extra time (knockout)
`soccer_team_extra_time_spread`	Soccer	Team	Extra time	Spread — extra-time goals only
`soccer_game_extra_time_total`	Soccer	Game	Extra time	Total goals across both teams, extra time only
`soccer_game_extra_time_btts`	Soccer	Game	Extra time	Both teams to score in extra time
`soccer_game_extra_time_first_team_to_score`	Soccer	Game	Extra time	First team to score in extra time
`hockey_team_full_game_winner`	Hockey	Team	Full game	Moneyline
`hockey_team_full_game_spread`	Hockey	Team	Full game	Spread (puck line)
`hockey_team_full_game_total`	Hockey	Team	Full game	Total
`hockey_game_overtime`	Hockey	Game	Full game	Overtime yes/no
`hockey_game_double_overtime`	Hockey	Game	Full game	Double overtime yes/no
`hockey_player_goals`	Hockey	Player	Full game	Goals prop
`hockey_player_assists`	Hockey	Player	Full game	Assists prop
`hockey_player_points`	Hockey	Player	Full game	Points prop
`tennis_match_winner`	Tennis	Player	Match	Moneyline
`tennis_match_games_spread`	Tennis	Player	Match	Games spread
`tennis_match_sets_spread`	Tennis	Player	Match	Sets spread
`tennis_match_total_games`	Tennis	Match	Match	Total games
`tennis_match_total_sets`	Tennis	Match	Match	Total sets
`tennis_match_exact_score`	Tennis	Match	Match	Exact set score
`tennis_set_1_winner`	Tennis	Player	Set 1	Prop
`tennis_set_2_winner`	Tennis	Player	Set 2	Prop
`tennis_set_3_winner`	Tennis	Player	Set 3	Prop
`cricket_match_winner`	Cricket	Team	Match	Moneyline
`ufc_fight_winner`	UFC	Fighter	Fight	Moneyline
`ufc_method_of_victory`	UFC	Fighter	Fight	Method of victory
`ufc_go_the_distance`	UFC	Game	Fight	Go the distance yes/no
`ufc_round_of_victory`	UFC	Fighter	Fight	Round of victory
`ufc_round_of_finish`	UFC	Fight	Fight	Round of finish
`ufc_method_of_finish`	UFC	Fight	Fight	Method of finish
`esports_match_winner`	Esports	Team	Match	Moneyline
`esports_map_winner_1`	Esports	Team	Map 1	Prop
`esports_map_winner_2`	Esports	Team	Map 2	Prop
`esports_map_winner_3`	Esports	Team	Map 3	Prop
`esports_map_winner_4`	Esports	Team	Map 4	Prop
`esports_game_winner_1`	Esports	Team	Game 1	Prop
`esports_game_winner_2`	Esports	Team	Game 2	Prop
`esports_game_winner_3`	Esports	Team	Game 3	Prop
`esports_game_winner_4`	Esports	Team	Game 4	Prop

The market_sport_type enum is the source of truth for sport, period, and prop variants, and is now guaranteed to be present on every instrument. When in doubt about which value applies to a market you’re seeing, use this field rather than parsing the symbol.

Section 2: Identifying Markets

Use this table as a recipe book for identifying a specific market type from instrument metadata. Match on market_sport_type alone — it fully identifies any market (structure and period), so you no longer need to check outcome_type.

To identify…	`market_sport_type`
Full-game moneyline	`<sport>_team_full_game_winner` (soccer uses `soccer_team_full_time_winner`, a 3-way market)
Full-game spread	`<sport>_team_full_game_spread`
Full-game total	`<sport>_team_full_game_total`
MLB first-5-innings moneyline	`baseball_team_first_five_winner`
MLB first-5-innings spread	`baseball_team_first_five_spread`
MLB first-5-innings total	`baseball_team_first_five_total`
MLB first-inning run	`baseball_team_first_inning_run`
MLB player home runs prop	`baseball_player_home_runs`
MLB player strikeouts prop	`baseball_player_strikeouts`
NBA first-half moneyline	`basketball_team_first_half_winner`
NBA first-half spread	`basketball_team_first_half_spread`
NBA first-half total	`basketball_team_first_half_total`
NBA player points prop	`basketball_player_points`
NBA player assists prop	`basketball_player_assists`

Worked Example: Cleveland/Detroit Over 4.5 Total

A full-game total on the May 21 Cleveland Guardians vs Detroit Tigers MLB game:

{
  "symbol": "tsc-mlb-cle-det-2026-05-21-4pt5",
  "metadata": {
    "event_id": "mlb-cle-det-2026-05-21",
    "event_start_time": "2026-05-21 17:10:00+00",
    "event_subcategory": "BASEBALL",
    "outcome_type": "totals",
    "market_sport_type": "baseball_team_full_game_total",
    "outcome_strike": "4.5",
    "long_participant_id": "mlb-cle",
    "long_participant_name": "Cleveland Guardians",
    "short_participant_id": "mlb-det"
  }
}

To safely interpret this contract:

market_sport_type = "baseball_team_full_game_total" → full-game total. (outcome_type is also present but you don’t need it.)
event_subcategory = "BASEBALL" → MLB game.
outcome_strike = "4.5" → over/under line is 4.5 combined runs.
The contract resolves “Over” if the combined score is 4.5 or more, otherwise “Under”.

Worked Example: Cleveland +3.5 Spread

A full-game run-line spread on the May 20 Cleveland Guardians vs Detroit Tigers MLB game:

{
  "symbol": "asc-mlb-cle-det-2026-05-20-pos-3pt5",
  "metadata": {
    "event_id": "mlb-cle-det-2026-05-20",
    "event_start_time": "2026-05-20 22:40:00+00",
    "event_subcategory": "BASEBALL",
    "outcome_type": "spreads",
    "market_sport_type": "baseball_team_full_game_spread",
    "outcome_strike": "3.5",
    "long_participant_id": "mlb-cle",
    "long_participant_name": "Cleveland Guardians",
    "short_participant_id": "mlb-det"
  }
}

To safely interpret this contract:

market_sport_type = "baseball_team_full_game_spread" → full-game spread. (outcome_type is also present but you don’t need it.)
long_participant_id = "mlb-cle" → the contract pays out on Cleveland.
outcome_strike = "3.5" → handicap magnitude is 3.5 runs.
The contract resolves to Cleveland if Cleveland wins, or loses by fewer than 3.5 runs.

Best Practices

Never parse the symbol or slug to determine market type, period, or handicap. Symbol formats are not part of the public contract.
Map on market_sport_type alone. It is guaranteed on every instrument — full-game, sub-period, and prop alike — and fully identifies the market. outcome_type is still present on the instrument, but do not rely on it for mapping (it is subject to change); the sole exception is futures, which carry no market_sport_type and are identified by outcome_type = "futures".
Treat outcome_strike as a string in client code and convert to your numeric type. The value is unsigned — the spread direction is determined by long_participant_id.
Cache and version your enum mappings. New market_sport_type values are announced in the changelog and rolled out in preprod before production. Subscribe to the RSS feed to be notified before new enums appear in production.
Subscribe to instrument updates via the streaming APIs to catch new instruments as they are listed.

​Section 1: Common Identifying Fields

​Field Reference

​outcome_type Enum

​market_sport_type Enum

​Section 2: Identifying Markets

​Worked Example: Cleveland/Detroit Over 4.5 Total

​Worked Example: Cleveland +3.5 Spread

​Best Practices

Section 1: Common Identifying Fields

Field Reference

`outcome_type` Enum

`market_sport_type` Enum

Section 2: Identifying Markets

Worked Example: Cleveland/Detroit Over 4.5 Total

Worked Example: Cleveland +3.5 Spread

Best Practices