Guide
Kalshi trading bot: automating regulated event contracts
Kalshi is a CFTC-regulated exchange with a signed API, cash settlement in USD, and a catalogue of recurring series that list on a schedule. That combination makes it the better venue for systematic strategies — you get repeatable contract structures and clean resolution sources — but its explicit fee curve means edge has to be measured after fees, not before.
How an automated Kalshi bot works
01Authenticate with a signed API key
Kalshi issues an API key pair, and every request is signed with your private key rather than sent with a bearer token. A bot needs secure key storage, correct request signing, and clock discipline — a skewed timestamp is the most common cause of a rejected order.
02Subscribe to the book over WebSocket
Polling REST endpoints for quotes burns rate limit and arrives late. A live bot multiplexes WebSocket subscriptions across its whitelisted tickers for orderbook deltas, trades and fills, and reconciles against REST snapshots on reconnect.
03Model the series, not the single market
Because Kalshi series recur, a bot can build a base rate from the history of the same contract structure — how often a CPI range printed, how a weather series behaved into settlement — and treat the live book as a deviation from that base rate.
04Size after fees, then execute and reconcile
The fee curve peaks around 50c, so the fee-adjusted edge on a coin-flip market is materially smaller than the raw spread suggests. Every fill is reconciled against the exchange's own fill records so the ledger, the P&L and the exchange never disagree.
Strategies traders automate
Recurring-series mean reversion
Standardized monthly and weekly series build a usable price history. When a contract drifts away from where the equivalent contract has historically traded at the same point in its lifecycle, and no new information explains it, that is a testable signal.
Macro data pre-positioning
CPI, payrolls and Fed contracts reprice against a published consensus. A bot ingesting the consensus and its own nowcast can take a position ahead of the print and, more reliably, trade the correlated ranges that lag the headline number.
Fee-aware market making
Quoting both sides works on Kalshi only where the spread comfortably exceeds the fee on both legs. In practice this pushes market making toward contracts away from 50c, where the fee is smaller, and toward series with steady retail flow.
Cross-venue arbitrage with Polymarket
The same question — an election, a rate decision, a crypto price level — is often listed on both venues at different prices. A bot takes the cheap side on one book and hedges the other, provided the resolution criteria genuinely match. Wording differences, not price, are what break this trade.
Weather and index range ladders
Kalshi lists outcome ranges as ladders. Their prices should form a coherent distribution; when one rung is out of line with its neighbours, a bot can trade the rung against the adjacent ones with a defined maximum loss.
Risk controls that matter
A bot without limits is just a faster way to lose money. Every automation you run in Infiniti sits behind hard, server-side guardrails:
- Per-order and per-series notional caps enforced server-side before submission.
- A daily loss limit that cancels resting orders, flattens exposure and halts the bot.
- Fee-adjusted edge thresholds, so no order is sent unless it clears the Kalshi fee on both legs.
- Rate-limit budgeting and backoff so the bot is never throttled mid-execution.
- A settlement blackout window that blocks new risk close to a contract's resolution.
- Continuous reconciliation of local fills against the exchange's fill records, with alerts on any mismatch.
What is specific to Kalshi
The fee curve is the strategy constraint
Fees scale with contract price and are heaviest near 50c, which is where most volume sits. Any strategy that turns over frequently in that range needs an edge visibly larger than the round-trip fee, or it is a slow transfer to the exchange.
Regulated custody and eligibility
Funds sit at a CFTC-regulated exchange rather than in a self-custody wallet, and access is gated by account eligibility. That removes on-chain and oracle risk but adds account, withdrawal and eligibility considerations to your operational plan.
Clean, published resolution sources
Kalshi resolves against a named published source with no dispute window to wait out. For a bot that holds to expiry, this materially reduces resolution ambiguity compared with oracle-settled venues.
Run it inside Infiniti
Infiniti Terminal connects your Kalshi account, streams the live book, runs AI research over it, and executes and journals every fill in one ledger — so backtest, live P&L and audit trail all read from the same data.
FAQ
Does Kalshi allow API trading bots?
Yes. Kalshi publishes an authenticated REST and WebSocket API for its event contracts, with orders signed using an API key pair. Programmatic access is a supported part of the exchange, subject to its rate limits and terms.
How do Kalshi fees affect a bot?
Kalshi charges an explicit fee that scales with contract price and peaks near 50c, exactly where most active markets trade. Any high-frequency strategy has to price that fee into its edge calculation before submitting an order, or it will look profitable on paper and lose money live.
What are the best markets to automate on Kalshi?
Recurring, standardized series — CPI, Fed decisions, jobs prints, weather and index levels. Because the same contract structure lists month after month, you get comparable history to backtest against, which one-off markets never give you.
Can one bot trade both Kalshi and Polymarket?
Yes, and that is where a lot of the edge is. When the same question is listed on both venues, a bot watching both books can take the cheap side and hedge the other. Infiniti connects both accounts behind one ledger so the hedged position is tracked as a single exposure.
Educational information only, not financial advice. Automated trading carries risk of loss. Fee schedules, API terms and eligibility rules change — confirm current terms with Kalshi before deploying capital.