Kalshi Trading

Trade real USD on Kalshi prediction markets using your AI agent and a self-custody Solana wallet

Kalshi is a regulated prediction market exchange offering real-money trading in USD. Aionmarket connects your agent to Kalshi via DFlow — a quote → local sign → submit flow that keeps your Solana private key entirely on your machine.

Venue identifier: Always pass "venue": "kalshi" when calling Kalshi endpoints.

How it works

Agent calls POST /kalshi/quote
  ↓  DFlow returns unsignedTransaction
Agent signs the transaction locally (SOLANA_PRIVATE_KEY)
  ↓
Agent calls POST /kalshi/submit with signedTransaction
  ↓  Server broadcasts to Solana RPC, records order in mk_order
Order is live on Kalshi

The server never sees your private key. All signing happens inside your agent or SDK.

Setup requirements

Requirement	Details
Claimed agent	POST /agents/register + claim link
Solana wallet	Base58-encoded secret key in SOLANA_PRIVATE_KEY
SOL for gas	~0.01 SOL per transaction on Solana mainnet
USDC on Solana	Trading capital (native USDC on Solana mainnet)
KYC verification	Required for BUY orders — complete at dflow.net/proof

---

1. Discover Kalshi markets

Kalshi markets are identified by ticker (e.g. KXHIGHNY-26FEB19-T70). Browse available markets through the standard markets endpoint filtered to Kalshi, or use the DFlow briefing for opportunities.

# Search Kalshi markets
curl -H "Authorization: Bearer YOUR_API_KEY" \
  "https://www.aionmarket.com/bvapi/markets?q=weather&venue=kalshi&limit=10"

from aion_sdk import AionMarketClient

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

markets = client.get_markets(q="weather", venue="kalshi", limit=10)
for m in markets:
    print(f"{m['marketId']}: {m.get('question', '')}")

---

2. Get a quote

Call POST /kalshi/quote to receive an unsigned transaction from DFlow. This does not execute any trade — it only prepares the transaction payload.

curl

curl -X POST "https://www.aionmarket.com/bvapi/kalshi/quote" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "marketId": "KXHIGHNY-26FEB19-T70",
    "side": "YES",
    "action": "BUY",
    "amount": 10,
    "userPublicKey": "YOUR_SOLANA_WALLET_ADDRESS",
    "source": "sdk:kalshi-weather",
    "reasoning": "NOAA forecast indicates edge"
  }'

Python SDK

quote = client.kalshi_quote(
    market_id="KXHIGHNY-26FEB19-T70",
    side="YES",
    action="BUY",
    amount=10,
    user_public_key="YOUR_SOLANA_WALLET_ADDRESS",
    source="sdk:kalshi-weather",
    reasoning="NOAA forecast indicates edge",
)

  quote_id = quote["quoteId"]
  unsigned_tx = quote["unsignedTransaction"]

Quote response fields:

Field	Description
quoteId	ID to include in /kalshi/submit
unsignedTransaction	Base64-encoded Solana transaction to sign
expiresAt	Unix ms timestamp — quote expires in ~5 minutes
previewOnly	true when userPublicKey is omitted (BUY preview only, no signing required)
kycRequired	true when wallet has not completed KYC

Quotes expire in ~5 minutes. Call /kalshi/submit promptly after signing. If you receive Quote expired or not found, request a new quote.

---

3. Sign the transaction locally

The unsignedTransaction field is a base64-encoded Solana transaction. Sign it with your Solana keypair before submitting.

import base64
from solders.transaction import VersionedTransaction
from solders.keypair import Keypair

# Load keypair from base58 secret key
import base58
secret = base58.b58decode("YOUR_BASE58_PRIVATE_KEY")
keypair = Keypair.from_bytes(secret)

# Decode and sign
raw = base64.b64decode(unsigned_tx)
txn = VersionedTransaction.from_bytes(raw)
signed_txn = keypair.sign_message(bytes(txn.message))

# Re-serialize (exact method depends on solders version)
import base64
signed_tx_b64 = base64.b64encode(bytes(txn)).decode()

The Python SDK (pip install aion-sdk>=1.0.0) handles signing automatically when SOLANA_PRIVATE_KEY is set. You do not need to implement signing manually.

---

4. Submit the signed transaction

curl

curl -X POST "https://www.aionmarket.com/bvapi/kalshi/submit" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "quoteId": "qt_1234567890",
    "signedTransaction": "BASE64_SIGNED_TX",
    "userPublicKey": "YOUR_SOLANA_WALLET_ADDRESS",
    "source": "sdk:kalshi-weather",
    "reasoning": "NOAA forecast indicates edge"
  }'

Python SDK

result = client.kalshi_submit(
    quote_id=quote_id,
    signed_transaction=signed_tx_b64,
    user_public_key="YOUR_SOLANA_WALLET_ADDRESS",
    source="sdk:kalshi-weather",
    reasoning="NOAA forecast indicates edge",
)

  order_id = result["orderId"]
  status = result["status"]
print(f"Order {order_id} is {status}")

A successful submit records the order in the platform database and returns:

Field	Description
orderId	Local order ID (use for cancel)
venueOrderId	Kalshi’s own order ID
status	OPEN, MATCHED, CANCELED, INVALID
filledSize	Filled share amount so far
avgPrice	Average fill price (0–1)
syncedToMkOrder	true when the order is recorded in the platform

---

5. Complete Python SDK workflow

from aion_sdk import AionMarketClient
import os

client = AionMarketClient(
    api_key=os.environ["AIONMARKET_API_KEY"],
    base_url="https://www.aionmarket.com/bvapi",
)

# 1. Quote
quote = client.kalshi_quote(
    market_id="KXHIGHNY-26FEB19-T70",
    side="YES",
    action="BUY",
    amount=10,
    user_public_key=os.environ["SOLANA_WALLET_ADDRESS"],
    source="sdk:my-kalshi-skill",
    reasoning="Forecast edge detected",
)

  if not quote.get("quoteId"):
    raise RuntimeError("Failed to get Kalshi quote")

# 2. Sign  (SDK handles when SOLANA_PRIVATE_KEY env var is set)
# 3. Submit
result = client.kalshi_submit(
    quote_id=quote["quoteId"],
    signed_transaction=quote["_signed"],   # SDK auto-signs
    user_public_key=os.environ["SOLANA_WALLET_ADDRESS"],
    source="sdk:my-kalshi-skill",
    reasoning="Forecast edge detected",
)

  print(f"Order {result['orderId']} | status: {result['status']}")

---

6. Monitor positions

Check open Kalshi positions for a wallet address.

curl

curl -X POST "https://www.aionmarket.com/bvapi/kalshi/positions" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "walletAddress": "YOUR_SOLANA_WALLET_ADDRESS",
    "limit": 20,
    "offset": 0
  }'

Python SDK

positions = client.kalshi_positions(
    wallet_address="YOUR_SOLANA_WALLET_ADDRESS",
    limit=20,
    offset=0,
)

for pos in positions["items"]:
    print(f"{pos['marketId']} | {pos['side']} | size={pos['size']} | pnl={pos['unrealizedPnl']}")

---

7. Cancel an order

Cancel an open order by its local orderId or Kalshi’s venueOrderId.

curl

curl -X POST "https://www.aionmarket.com/bvapi/kalshi/cancel" \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "orderId": "ks_abcd1234",
    "walletAddress": "YOUR_SOLANA_WALLET_ADDRESS",
    "reason": "strategy exit"
  }'

Python SDK

cancel = client.kalshi_cancel(
    wallet_address="YOUR_SOLANA_WALLET_ADDRESS",
    order_id="ks_abcd1234",
    reason="strategy exit",
)

print(cancel["statusAfter"])   # "CANCELED"

---

SELL flow

To exit a Kalshi position, use POST /kalshi/quote with "action": "SELL" and pass shares instead of amount.

{
  "marketId":       "KXHIGHNY-26FEB19-T70",
  "side":           "YES",
  "action":         "SELL",
  "shares":         12.5,
  "userPublicKey":  "YOUR_SOLANA_WALLET_ADDRESS"
}

KYC is not required for SELL orders.

---

Error reference

Error	Cause	Fix
KYC_REQUIRED	Wallet not verified for BUY	Complete KYC at dflow.net/proof
QUOTE_EXPIRED	Quote older than ~5 minutes	Request a new quote
GEO_BLOCKED	Trading restricted in your region	Check KALSHI_GEO_BLOCK_COUNTRIES in your env
Quote expired or not found	DFlow upstream error	Request a new quote and submit immediately
Invalid account owner	No USDC token account on Solana	Send USDC to your Solana wallet
No Solana wallet linked	Wallet not registered	Upgrade SDK or call quote with userPublicKey
Transaction did not pass signature verification	Stale SDK or signing error	Re-sign with current SDK

---

Maintenance window

Kalshi’s clearinghouse has a weekly maintenance window on Thursdays 3:00–5:00 AM ET. Orders submitted during this window will fail. Build retry logic around this window.

---

Platform Fee (REQUIRED)

Kalshi fees are NOT collected automatically by default. The agent must call charge_kalshi_fee() after every successful order submission, or rely on kalshi_submit(auto_charge_fee=True).

Every Kalshi trade is subject to a 1% platform fee on the order amount, charged in native USDC (SPL Token) on Solana.

Fee charging flow

# After successful kalshi_submit():

# REQUIRED: Charge the 1% platform trading fee
fee_amount = f"{order_amount * 0.01:.6f}"
fee_result = client.charge_kalshi_fee(
    amount=fee_amount,
    from_address=sol_wallet_address,
)
print(f"Fee: ${fee_result['feeAmount']} USDC")
print(f"Status: {fee_result['status']}")  # PENDING → confirmed async

Fee details

Property	Value
Fee rate	1% of order amount
Token	USDC (SPL Token on Solana mainnet)
Platform address	CHMkL5utJWFFHSkHX6pwWcb8VXj5jAz5fAqqMGAyEXcX
Collection	Manual — agent calls POST /aiagent/charge-fee/kalshi/trade-fee
Commission	10% of fee credited to agent automatically

Prerequisites

• User’s Solana wallet must hold sufficient USDC (order amount + 1% fee + gas)
• User must grant USDC token approval to platform vault
• The agent can use the local SOLANA_PRIVATE_KEY to sign the approval transaction

---

Next steps

• Kalshi Quote API reference
• Kalshi Submit API reference
• Charge Kalshi Fee API reference
• Wallet Setup — Kalshi (Solana)
• Trading Guide (Polymarket)