OpenMarkets · DevelopersConsole ↗

Quickstart

X-API-Key · GET /flow/v1/leagues · wss://…/flow/v1/stream

A key, one call, one stream. About a minute, and nothing here needs approval.

1. Create a key

Console → API keys

Sign in to the console and create a key on the API keys page. Every plan, including Free, gets a key that reads prices and places practice orders; real money needs one linked to a venue account (see Connect). The key looks like om_exec_live_… — the prefix names the key type and the environment.

The plaintext is shown once. Store it in a secret manager straight away — OpenMarkets keeps only the hash and cannot recover the original. Lost it? Revoke and create another.

2. See tonight's game

GET /flow/v1/public/live-sample (no key needed) returns whichever open contest the most venues are quoting right now — the same one the console's front door shows. Take its contest_id and read its aggregated liquidity on your own key — every bettable outcome, every venue:

curl
curl https://api.openmarkets.ai/flow/v1/contests/{contest_id}/liquidity \
  -H "X-API-Key: om_exec_live_..."

The response:

Response
{
  "data": [
    {
      "position": "home",
      "title": "Kansas City to win",
      "price": 0.57,
      "available": 5400,
      "liquidity_hash": "kalshi:ct_9f2a...:mk_ml:side_home:var_0"
    }
  ],
  "meta": { "timestamp": "2026-09-28T00:04:00Z", "api_version": "v1" }
}

Each position carries a per-venue best price, the size available at it, and a consensus price. The full shape is in the REST reference; how to lay positions out into books is in Market model & books.

3. Place a practice order

Every key can place practice orders — mode: "paper", play money, graded when the game ends. Same request with mode: "real" once a venue is linked.

curl
curl https://api.openmarkets.ai/flow/v1/auth/orders/buy \
  -H "X-API-Key: om_exec_live_..." \
  -H "Content-Type: application/json" \
  -d '{
    "orders": [{
      "liquidity_hash": "kalshi:ct_9f2a...:mk_ml:side_home:var_0",
      "amount": 10,
      "max_price": 0.57,
      "mode": "paper"
    }]
  }'

See Trading for order types, multi-leg requests and error codes.

4. Add Sign in with OpenMarkets

One button gives your app's users a key scoped to what they approve — no password, no venue login, ever in your code. See Sign in with OpenMarkets for registering an app and reading the consent result.

5. Stream live updates

stream:realtime

Open a WebSocket and subscribe to the contests you care about. You receive a liquidity.update whenever any venue's price or size changes.

Node.js
import WebSocket from 'ws';

const ws = new WebSocket(
  'wss://api.openmarkets.ai/flow/v1/stream?api_key=om_exec_live_...'
);

ws.on('open', () => {
  ws.send(JSON.stringify({
    action: 'subscribe',
    channel: 'liquidity',
    contest_ids: ['ct_abc123'],
  }));
});

ws.on('message', (data) => {
  const msg = JSON.parse(data.toString());
  if (msg.type === 'liquidity.update') {
    console.log(msg.contest_id, msg.changed_entries);
  }
});

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