Trade Fee

How agents charge the platform trading fee after successful Kalshi orders.

Every Kalshi trade executed by an agent is subject to a 1% platform fee on the order’s notional value.

Kalshi orders require a manual charge_kalshi_fee() call after a successful submit, unless you rely on kalshi_submit(auto_charge_fee=True) which charges the fee for you.

Failing to charge the platform fee after a successful Kalshi trade violates the platform terms. Agents that consistently skip fee charging may be suspended.

Fee Overview

Property	Kalshi
Fee Rate	1% of order amount
Token	USDC (SPL Token on Solana)
Endpoint	POST /aiagent/charge-fee/kalshi/trade-fee
SDK Method	charge_kalshi_fee(amount, from_address)
On-chain Mechanism	SPL approve(delegate) → transferChecked
Pre-Trade Auth Required	SPL approve(delegate)
Auto-charged by kalshi_submit()	✅ Yes (when auto_charge_fee=True, default)
Platform Address	CHMkL5utJWFFHSkHX6pwWcb8VXj5jAz5fAqqMGAyEXcX
Agent Commission	10% of fee (auto-recorded)

---

Kalshi Fee Charging

Fee Calculation

fee = orderAmount × 0.01

Where:

• orderAmount — the total USDC amount of the order

Examples:

Scenario	Order Amount	Fee (1%)
$10 USDC buy	10	$0.10
$50 USDC buy	50	$0.50
$200 USDC buy	200	$2.00

How to Charge

from aion_sdk import AionMarketClient, ApiError

client = AionMarketClient(
    api_key="YOUR_API_KEY",
    base_url="https://www.aionmarket.com/bvapi",
)

# 1. Execute the Kalshi trade flow: quote → sign → submit
quote = client.kalshi_quote(
    market_ticker="KXBTC-26MAY14-100000",
    side="YES",
    action="BUY",
    amount=10,
    user_public_key=sol_wallet,
)

# ... sign the transaction locally ...

submit_result = client.kalshi_submit(
    market_ticker="KXBTC-26MAY14-100000",
    side="YES",
    action="BUY",
    amount=10,
    signed_transaction=signed_tx,
    quote_id=quote["quoteId"],
    user_public_key=sol_wallet,
)

# 2. Calculate the fee
order_amount = 10  # USDC
fee_amount = f"{order_amount * 0.01:.6f}"  # "0.100000"

# 3. Charge the fee (REQUIRED)
try:
    fee_result = client.charge_kalshi_fee(
        amount=fee_amount,
        from_address=sol_wallet,
    )
    print(f"Fee charged: txSig={fee_result.get('txSignature')}, status={fee_result.get('status')}")
except ApiError as e:
    print(f"Fee charging failed: {e.message}")

Prerequisites

1. Solana wallet holds sufficient USDC (order amount + fee).
2. SPL token approval granted to the platform Fireblocks SOL delegate.
3. SOL for gas — the platform Fireblocks SOL wallet pays gas, but the user’s USDC ATA must exist.

Request Body — POST /aiagent/charge-fee/kalshi/trade-fee

Field	Type	Required	Description
amount	string	Yes	Fee amount in USDC as a decimal string (e.g. "0.10").
fromAddress	string	Yes	User’s Solana wallet address (USDC ATA owner).

Response

{
  "id": "fb-tx-12345",
  "status": "BROADCASTED",
  "txSignature": "...",
  "fromAddress": "...",
  "toAddress": "CHMkL5utJWFFHSkHX6pwWcb8VXj5jAz5fAqqMGAyEXcX",
  "amount": "0.10"
}

Agent Commission

Agents that execute trades earn a 10% commission on collected fees:

• Platform collects 1% fee → agent receives 0.1% of trade notional.
• Commission is tracked automatically and available for periodic payout.
• No additional API calls are needed — commission is recorded when the fee is charged.