STX Prediction API Documentation

Build on the STX Prediction Platform

Trade programmatically or build apps for STX members. Real markets, real-time data, developer-first.

• Live book
• REST API
• WebSockets
• SDKs

Trade

Trade with your own account

An API key, signed requests and live fills. Use the REST API, WebSockets or an SDK.

Quick start →

RESTWebSocketSDK

POST /api/v1/orders
// signed: X-STX-ACCESS-* headers
{
  "market_id": "9d42e9c9-…",
  "action": "buy",
  "order_type": "limit",
  "price": "0.42",
  "quantity": "10"
}

// /socket/websocket?vsn=2.0.0
["1", "1", "orderbook",
 "phx_join",
 {"market_ids": ["9d42e9c9-…"]}]

// then a "book" push per market:
{"market_id": "9d42e9c9-…",
 "bids": [...], "offers": [...]}

import { STX } from
  "@stxapp/stx-typescript";

const client = new STX();
await client.placeOrder(
  marketId, "buy", "limit",
  { price: "0.42",
    quantity: "10" }
);

STXPrediction
Platform

Build

Build an app for STX members

Your users connect their STX accounts, and your app trades for them with the access they approve.

Start with ISV →

1. Your app
3. OAuth
5. STX memberAccounts and permissions
7. STX Prediction Platform

New to prediction markets? Concepts covers binary contracts, matching, liability and settlement.

One order, end to end

Place it over REST, get the response, then watch the fill arrive on your socket.

1Place an order

curl -X POST https://demo.stxapp.io/api/v1/orders \
  -H "X-STX-ACCESS-KEY: $KEY_ID" \
  -H "X-STX-ACCESS-TIMESTAMP: $TS" \
  -H "X-STX-ACCESS-SIGNATURE: $SIG" \
  -H "Content-Type: application/json" \
  -d '{"market_id":"2bc3d8d8-…",
      "action":"buy","order_type":"limit",
      "price":"0.42","quantity":"10"}'

2REST · 200accepted

{
  "order": {
    "id": "7dc6671e-2852-…",
    "status": "accepted",
    "price": "0.4200",
    "quantity": "10.00",
    "filled": "0.00",
    "avg_price": null, …
  }
}

3Socket · ordersfilled

[null, null, "orders:<user_id>",
 "new_open_order", {
   "id": "7dc6671e-2852-…",
   "status": "filled",
   "quantity": "10.00",
   "filled": "10.00",
   "filled_percentage": 100,
   "avg_price": "0.4200", …
 }]

▋

Core operations

Markets and eventsQuery markets and events, filter by competition and status.

OrdersPlace and cancel orders; list your resting book. Re-quoting is cancel-then-place, with no atomic replace.

WebSocket channelsPhoenix channels for live market data, and your own orders, fills and positions.

PortfolioSettlements, deposits, withdrawals and loyalty.

Reference and tools

Live marketsA real order book, streaming, with no API key. See current spreads and depth before deciding whether to build.

Postman collectionEvery REST endpoint, with the Ed25519 signing script already wired in.

AuthenticationHow to sign a request with your Ed25519 key, in five languages, with a known key and signature to check your code against.

OAuthHow an app gets a member's consent: the authorization code flow, scopes, tokens and discovery.

SDKsOfficial TypeScript, Python and C# clients: typed calls, signed requests and live channels, ready to install.

Examples on GitHubSigned requests, order placement and live channel watchers in Python and JavaScript.