Creating markets

An approved app can list player-prop markets on STX events. You name the event, the player, the stat and the line; STX builds the market, settles it from its stats feed, and returns one outcome for each market you asked for.

Creating markets is granted by STX, per app. It is not part of the standard ISV access.

Setup

STX enables your app for market creation:

• adds the markets.write app scope to your client. Only STX can grant it.
• sets your client’s IP allow-list to your servers’ egress addresses. Every write scope requires one, and a call from any other address is refused.

Ask your STX contact to enable it on the demo exchange first.

1. Get an app token

Request an app token with the client_credentials grant, as described in Tokens and security. Send it as Authorization: Bearer <access_token> on every call below, from an allow-listed address.

2. Find the event

GET /api/v1/events lists upcoming events. Take the event’s id. Markets can be created only while the event is scheduled and has not started.

3. Get the players

GET /api/v1/events/{event_id}/players returns each team’s roster and the stats a market can be created on.

{
  "event_id": "ee2ee8f9-4326-4e4f-841a-1bc3f598dbd9",
  "teams": [
    {
      "team": "Utah Jazz",
      "players": [
        { "player_id": "4873138", "name": "Ace Bailey", "jersey": "19", "position": "G" }
      ]
    }
  ],
  "stats": [
    { "stat": "POINTS", "name": "Points" },
    { "stat": "REBOUNDS", "name": "Rebounds" }
  ]
}

• Rosters are the teams’ current rosters, not game-day actives, and can be up to 15 minutes old.
• teams is empty until a roster is published. Try again later.
• Send player_id back exactly as returned.

4. Create the markets

POST /api/v1/markets takes the event and up to 25 markets, each described by a stat_detail:

{
  "event_id": "ee2ee8f9-4326-4e4f-841a-1bc3f598dbd9",
  "markets": [
    { "stat_detail": { "player_id": "4873138", "stat": "POINTS", "prop_type": "ou", "line": 18.5 } },
    { "stat_detail": { "player_id": "4873138", "stat": "REBOUNDS", "prop_type": "ou", "line": 4.5 } }
  ]
}

Field	Value
player_id	From the players endpoint.
stat	One of the event’s stats.
prop_type	ou (over/under). Optional; ou is the only type today.
line	A positive half line, such as 18.5.

The response is 200 with one outcome per market, in request order:

{
  "event_id": "ee2ee8f9-4326-4e4f-841a-1bc3f598dbd9",
  "markets": [
    { "status": "created", "market_id": "5766e668-b5ad-4db4-8dd1-e1b7f27d9974",
      "stat_detail": { "player_id": "4873138", "stat": "POINTS", "prop_type": "ou", "line": 18.5 } },
    { "status": "exists", "market_id": "4b2b8139-7968-4a20-b760-f6751af88f06",
      "stat_detail": { "player_id": "4873138", "stat": "REBOUNDS", "prop_type": "ou", "line": 4.5 } }
  ]
}

• created: a new market. STX sets its title, rules and price range.
• exists: an open market for the same player, stat and line is already on the event. Its market_id is returned and nothing new is created, so resending a request is always safe.
• rejected: not created. reason is one of invalid_market, unsupported_market_type, unsupported_prop_type, unsupported_stat, invalid_line, unknown_player, event_not_open or not_created.

A whole request can also fail:

Status	Meaning
400	Malformed body, or more than 25 markets.
401	Missing or invalid token.
403	Not an app token with markets.write, or a call from outside the IP allow-list.
404	Unknown event.
422	event_not_open, unsupported_event (no player props for this event) or roster_unavailable.

5. Quote the markets

The new markets behave like any other STX market. Find them with GET /api/v1/markets and the market data channels, and quote them with your market-making account’s API key through the orders endpoints. STX settles them from its stats feed when the game ends.

With the TypeScript SDK

@stxapp/stx-typescript 0.8.0 and later wrap these calls. createMarkets() returns the same per-market results, and validate: true checks players, stats and lines before sending (it reads the event’s players, so the token also needs events).

import { AppScopes, OAuthClient } from "@stxapp/stx-typescript/oauth";

const oauth = new OAuthClient({ clientId, clientSecret });
const stx = oauth.appClient([AppScopes.EVENTS, AppScopes.MARKETS_WRITE]);

const roster = await stx.eventPlayers(eventId);
const player = roster.teams[0].players[0];

const results = await stx.createMarkets(
  eventId,
  [
    { playerId: player.player_id, stat: "POINTS", line: 18.5 },
    { playerId: player.player_id, stat: "REBOUNDS", line: 4.5 },
  ],
  { validate: true },
);
for (const r of results) console.log(r.status, r.status === "rejected" ? r.reason : r.market_id);