Placing Trades - Predexon API

This guide covers the full trading workflow on the accounts path (/api/accounts/*).

Find a market

Before placing a trade, fetch the venue-specific identifiers for the outcome you want to trade from the Data API. Pass them to the Trading API in a market bag.

import requests
HEADERS = {"x-api-key": "YOUR_API_KEY"}

markets = requests.get(
    "https://api.predexon.com/v2/polymarket/markets",
    headers=HEADERS,
    params={"status": "open", "sort": "volume", "limit": 5},
).json()

for m in markets["markets"]:
    print(m["title"])
    for o in m["outcomes"]:
        print(f"  {o['label']}  token_id={o['token_id']}")

Each venue requires a different combination of fields in the market bag:

Venue	Required `market` fields	Notes
Polymarket	`tokenId`	Each outcome (Yes/No) has its own token ID.
Predict	`tokenId` + `marketId`	Both required - `marketId` is the numeric Predict market ID.
Opinion	`tokenId` + `marketId`	Both required - `tokenId` identifies the outcome side, `marketId` is the numeric Opinion market ID.
Limitless	`tokenId` + `marketSlug`	`marketSlug` identifies the Limitless market (e.g., `"btc-up-or-down-1-hour-1778011201918"` - real slugs include a unix-millis suffix).
Hyperliquid	`assetId`	Identifies a specific HIP-4 outcome side.

Choose an order type

Market orders

Execute immediately at the best available price.

Market BUY - specify amount (stablecoin to spend). Fills as many shares as possible. (Hyperliquid: takes size, not amount.)
Market SELL - specify size (shares to sell). Sells at the best available price.

Limit orders

Sit on the orderbook at a specific price until someone takes the other side.

Limit BUY / SELL - specify size and price. Order rests until matched.

Amount vs size vs price

Order Type	Required	Rejected
Market BUY	`amount`	`size`
Market SELL	`size`	`amount`
Limit BUY	`size` + `price`	`amount`
Limit SELL	`size` + `price`	`amount`

Sending the wrong field returns a 400 with a message indicating which field was expected.

Place an order

All orders go to POST /api/accounts/{accountId}/orders with venue set to polymarket, predict, opinion, limitless, or hyperliquid. See the Place Order reference for the full schema and per-venue examples.

Polymarket

BASE = "https://trade.predexon.com"
HEADERS = {"x-api-key": "YOUR_API_KEY", "Content-Type": "application/json"}
account_id = "YOUR_ACCOUNT_ID"

order = requests.post(
    f"{BASE}/api/accounts/{account_id}/orders",
    headers=HEADERS,
    json={
        "venue": "polymarket",
        "market": {"tokenId": "71321045679252212"},
        "side": "buy",
        "type": "market",
        "amount": "10",
    },
).json()
print(f"{order['orderId']} - status: {order['status']}, filled: {order['filled']}")

Predict

order = requests.post(
    f"{BASE}/api/accounts/{account_id}/orders",
    headers=HEADERS,
    json={
        "venue": "predict",
        "market": {
            "tokenId": "103210916722172747942846166716572235061234589599991001208035034049741504775450",
            "marketId": "46954",
        },
        "side": "buy",
        "type": "market",
        "amount": "10.00",
    },
).json()

Opinion

Opinion requires both tokenId (the outcome side) and marketId (the numeric market ID).

order = requests.post(
    f"{BASE}/api/accounts/{account_id}/orders",
    headers=HEADERS,
    json={
        "venue": "opinion",
        "market": {"tokenId": "9123", "marketId": "123"},
        "side": "buy",
        "type": "limit",
        "size": "10",
        "price": "0.42",
    },
).json()

Limitless

Limitless requires both tokenId and marketSlug. Prices snap to 0.001 ticks; size supports up to 3 decimal places.

order = requests.post(
    f"{BASE}/api/accounts/{account_id}/orders",
    headers=HEADERS,
    json={
        "venue": "limitless",
        "market": {
            "tokenId": "55222001234567",
            "marketSlug": "btc-up-or-down-1-hour-1778011201918",
        },
        "side": "buy",
        "type": "limit",
        "size": "10",
        "price": "0.420",
    },
).json()

Hyperliquid

Hyperliquid uses assetId to identify a specific HIP-4 outcome side. Each side of each market has a unique integer assetId; for recurring markets like the daily BTC binary, the asset ID rotates each cycle - fetch the current value from your market data source before each order. Every order - buy or sell - must clear a $10 notional minimum (size × price ≥ 10).

order = requests.post(
    f"{BASE}/api/accounts/{account_id}/orders",
    headers=HEADERS,
    json={
        "venue": "hyperliquid",
        "market": {"assetId": "100000020"},
        "side": "buy",
        "type": "market",
        "size": "11",
    },
).json()

Note: on Hyperliquid, market BUY takes size (the share count to acquire), not amount.

Response shape

Account-path order responses use a normalized shape:

{
  "orderId": "0xe69245af3a00e487",
  "venue": "polymarket",
  "side": "buy",
  "outcome": "Yes",
  "status": "filled",
  "createdAt": "2026-04-15T10:30:00.000Z",
  "size": "15.38",
  "price": "0.6500",
  "filled": "15.38",
  "market": { "tokenId": "71321045679252212", "outcome": "Yes" },
  "fee": { "policyApplied": true, "feeBps": 50, "platformFeeBps": 0, "partnerFeeBps": 50 }
}

Venue differences

	Polymarket	Predict	Opinion	Limitless	Hyperliquid
Chain	Polygon	BSC	BSC	Base	HyperCore
Collateral	pUSD	USDT	USDT	USDC (native)	USDH (USDC-pegged)
`market` requires	`tokenId`	`tokenId` + `marketId`	`tokenId` + `marketId`	`tokenId` + `marketSlug`	`assetId`
Price tick	Per-market (typically 0.01)	Per-market (typically 0.01)	market-specific	0.001 (3 decimals)	up to 5 sig figs
Min order	Per CLOB (typically $1)	Per CLOB (typically $1)	market-specific	market-specific	$10 notional
Order queries	Full `market` bag	Full `market` bag	`tokenId` unavailable on reads - `market` contains `marketId` only	Full `market` bag	Full `market` bag
Fees	Configurable partner fee	Exchange fee varies by market (automatic)	Exchange fee varies by market (automatic)	Maker: 0%. Taker: 0.4%–3% per Limitless schedule	Per Hyperliquid HIP-4 schedule (automatic)

After placing an order

Monitor - Get Orders or Get Order
Cancel - Cancel Order or Cancel All Orders
Positions - filled orders appear in Get Positions
Redeem - when a market resolves, Redeem Position cashes out winnings

Next Steps

Funding & Withdrawals

Deposit and withdraw funds

Fees & Monetization

Set up partner fees to monetize your app

Place Order Reference

Full endpoint reference

Get Positions Reference

Full endpoint reference

​Find a market

​Choose an order type

​Market orders

​Limit orders

​Amount vs size vs price

​Place an order

​Polymarket

​Predict

​Opinion

​Limitless

​Hyperliquid

​Response shape

​Venue differences

​After placing an order

​Next Steps