Arena Markets API

openapi: 3.2.0
info:
  title: Arena Markets API
  version: 1.15.0
  summary: 'Arena with an API key: read Arena-owned data, place paper orders with trade:write, and send live orders to your own venue account with a venue''s live-order scope.'
  description: 'Arena Predictions (arena-predictions.com) is paper trading for prediction markets at live prices, in a sandbox, and live orders through the key owner''s own venue credentials. Paper is the default on every endpoint here (mode "paper"): a paper trade fills in Arena''s sandbox and is not sent to a venue. A live order is sent only when a request says execution kalshi or poly-intl with a key made with trade:write:kalshi or trade:write:poly-intl. It goes to the key owner''s own Kalshi or Polymarket International account with the venue credentials saved in Settings: real money at the venue, under the venue''s rules and terms. Arena is not a broker and never holds your funds. Polymarket International is not for US persons, and ProphetX orders are switched off (trade:write:prophetx is not issued, so execution prophetx is refused with 403 insufficient_scope; a key that carries the scope gets 503 trading_off). Keys read by default and reach Arena-owned data only: the key''s own identity and account, the leaderboards and published trader records with their resets and settled picks. Keys are managed with the signed-in browser session, never with a key. No exchange ticker, market title, entry price or venue price appears in a paper answer or a read while the venue-data switch is off; the owner''s own portfolio carries the owner''s own paper numbers (a resting order''s limitCents, a position''s costDollars and contracts). A live order''s answer names the venue''s own market and price (ticker, priceCents). Balances carry over: every account starts with 100,000 paper dollars, and a reset (at most one every 30 days, shown on a public profile) starts a new run. 1.2.0: seasons removed (no season field anywhere), leaderboard windows and kinds, trader resets, GET /account. 1.3.0: accounts are private by default. A private trader answers private: true with every P&L and rank null (resets and busts 0) and an empty pick list; a public trader whose earlier trades are still hidden has numbersShown: false and no P&L or rank. The key owner reads their own picks (each with placedPrivate and shown) and their own eval rows (GET /me/eval) with portfolio:read. No key can make an account public. 1.4.0: keys are managed by a person''s session, on the website or as a signed-in CLI''s session token (arena keys), never by a key; keys rotate with a grace period; every keyed answer carries the plan and its counts (RateLimit-*, Arena-Quota-*, Arena-Plan) and GET /usage says where the account stands; a new scope, markets:read, reads instruments, games and quotes; GET /portfolio and /portfolio/trades read the owner''s positions, orders and trades. Venue references and venue prices are served only while the venue-data switch is on (it ships off): until then the quotes routes answer 403 venue_data_off and nothing keyed names a ticker or a venue''s price. 1.5.0: GET /eval, the public eval board (records:read), each row with 95% intervals clustered by game. 1.6.0: GET /traders/{traderId}/track-record, a trader''s Ed25519-signed 90-day record exactly as Arena signed it (records:read; it names Kalshi series inside its signed bytes, so it is served only while the venue-data switch is on), and tiedWithAbove on each eval row (null while this row''s or the row above''s interval is unknown). 1.7.0: a key created with trade:write (only when asked for by name: the Settings checkbox, arena keys create --trade, or scopes in the body) places paper orders with POST /portfolio/orders and cancels them with DELETE /portfolio/orders/{orderId}, at Kalshi''s paths. Market and limit orders, buys by instrument or ticker and sells of a whole position, each with an idempotencyKey: the same key again answers the stored order with replayed: true and places nothing. Hard trade limits are always enforced: per key 10 new orders a minute and 50 a day, and 20 sells and cancels a minute; per account, across every key and connected app, 20 new orders a minute, 100 a day, and 40 sells and cancels a minute.'
  termsOfService: https://arena-predictions.com/terms
  contact:
    name: Arena
    email: support@zbgcllc.com
    url: https://arena-predictions.com/support
servers:
- url: https://arena-predictions.com/api/v1
  description: The Arena API. Paper trading, Arena's sandbox, is the default on every account. An order is sent to a venue only when the request says execution and the key carries that venue's scope.
tags:


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# Full source: https://artifacts.apis.io/arena-predictions-com/openapi/arena-predictions-com-markets-api-openapi.yml