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
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://pm-t1.bxingupdate.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
- Solana wallet holds sufficient USDC (order amount + fee).
- SPL token approval granted to the platform Fireblocks SOL delegate.
- 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.
