Arbitrage on prediction markets is conceptually simple: when two platforms price the same event differently enough, you buy on the cheaper side and sell (or buy the opposite contract) on the expensive side, locking in a profit regardless of the outcome. On Kalshi specifically, this gets interesting because you are dealing with a CFTC-regulated exchange that settles in U.S. dollars, has strict KYC requirements, and operates under position limits that other platforms do not impose.
The practical challenge is speed and accuracy. Kalshi event contracts cover economics data (CPI, jobs reports, Fed decisions), weather events, and other outcomes that also trade on Polymarket, PredictIt, and in some cases traditional derivatives markets. Pricing discrepancies are real but fleeting. A good arb bot needs to scan multiple data sources, calculate true implied probabilities after fees, and execute within seconds.
This guide ranks the best arbitrage bots purpose-built or adaptable for Kalshi trading as of March 2026. Every tool was evaluated against the same criteria, with particular attention to how well each handles Kalshi’s regulated environment.
For background on how prediction market arbitrage works at a technical level, see the cross-market arbitrage guide. For Kalshi-specific API details, see the Kalshi API guide.
What to Look for in a Kalshi Arbitrage Bot
Not every arb bot is suitable for Kalshi. The platform’s regulatory structure and technical architecture create specific requirements that generic crypto-market arb tools do not address. Here are the criteria that matter most:
1. Kalshi API Integration Depth
The bot must support Kalshi’s RSA-PSS authentication, REST API v2 endpoints, and ideally WebSocket streaming for real-time order book updates. Shallow API wrappers that only pull top-of-book prices miss the spread dynamics essential for accurate arb calculation. Look for FIX 4.4 support if you need institutional-grade latency.
2. Cross-Platform Data Coverage
Kalshi-only arbs (mispricing between related contracts on Kalshi itself) exist but are uncommon. The highest-value arbs come from cross-platform discrepancies — Kalshi vs. Polymarket, Kalshi vs. PredictIt, or Kalshi event contracts vs. equivalent traditional instruments. Your bot needs reliable data feeds from multiple sources.
3. Fee-Adjusted Calculations
Kalshi charges exchange fees on every trade (currently a tiered fee schedule starting at $0.07 per contract for most events). A bot that reports a 2% arb without accounting for fees on both legs is useless. Demand fee-adjusted calculations that show your net profit after all costs.
4. Position Limit Awareness
Kalshi imposes position limits on many event contracts — often capped at a few thousand contracts per market. Your arb bot needs to know these limits and size positions accordingly. An arb opportunity where you can only deploy $200 is very different from one where you can deploy $20,000.
5. Execution Speed and Reliability
Arb windows on prediction markets typically last seconds to low minutes. The bot needs reliable order execution with retry logic, partial fill handling, and awareness of Kalshi’s rate limits. A bot that detects an arb but takes 30 seconds to place the order will miss most opportunities.
Top Picks: Kalshi Arbitrage Bots Compared
| Bot | Type | Price Range | Best For | Rating |
|---|---|---|---|---|
| KalshiArb | Dedicated Kalshi arb scanner | $99-249/mo | Kalshi-focused traders who want a turnkey arb solution | 4.2/5 |
| CrossPlatform Agent | Multi-exchange arb framework | $149-399/mo | Traders arbing across Kalshi, Polymarket, and PredictIt | 4.1/5 |
| EventArb Pro | Event-contract specialist | $79-199/mo | Economics and weather event arb on Kalshi | 3.9/5 |
| PredictEngine (Kalshi module) | Hosted multi-strategy platform | $149-299/mo (platform) | Users already on PredictEngine wanting Kalshi arb | 3.8/5 |
| RegArb | Open-source arb framework | Free (self-hosted) | Developers who want full control and customization | 3.6/5 |
Detailed Reviews
KalshiArb
KalshiArb is the most Kalshi-native arb tool on this list. Built specifically for Kalshi’s API and contract structure, it handles RSA-PSS authentication natively, understands Kalshi’s tick sizes (contracts priced in cents from 1 to 99), and integrates Kalshi’s position limit data directly into its sizing calculations.
The scanner monitors Kalshi event contracts alongside corresponding markets on Polymarket and PredictIt. When it detects a fee-adjusted arb above your configured threshold (default: 1.5% net), it generates alerts and can auto-execute on the Kalshi leg. The cross-platform leg still requires manual execution or a separate integration, which is a practical limitation — but also a regulatory reality, since unified execution across regulated and unregulated venues raises compliance questions.
Where KalshiArb stands out is its event-specific logic. It understands that a “Fed rate decision” contract on Kalshi maps to a specific question on Polymarket, and it handles the translation between different contract structures (binary vs. ranged). The $99/month tier gets you scanning and alerts; the $249 tier adds auto-execution on Kalshi and historical arb analytics. The main gap is documentation — setup requires some trial and error, and support response times can stretch to 48 hours.
CrossPlatform Agent
CrossPlatform Agent takes the opposite approach from KalshiArb: instead of going Kalshi-deep, it goes wide. This is a multi-exchange arb framework that treats Kalshi as one of several connected venues. It also integrates Polymarket’s CLOB API, PredictIt’s API, and can pull in traditional market data from financial APIs for correlation-based arb detection.
The strength here is the unified opportunity feed. Rather than running separate tools for each platform, CrossPlatform Agent normalizes contract data across all connected exchanges into a single arb dashboard. It calculates implied probabilities for each venue, deducts venue-specific fees, and presents net arb opportunities ranked by expected profit. Execution is supported on all platforms via their respective APIs, though Kalshi execution uses the REST API (no FIX support yet).
The $149/month base plan supports two platforms with basic alerting. The $399/month plan unlocks all platforms, auto-execution, and a backtesting module that lets you simulate arb strategies against historical cross-platform pricing data. The drawback is breadth vs. depth: CrossPlatform Agent’s Kalshi integration is competent but not as nuanced as KalshiArb’s handling of Kalshi-specific contract types. It occasionally mismatches Kalshi contracts with their cross-platform equivalents, especially for less-liquid event categories.
EventArb Pro
EventArb Pro focuses on a specific niche: arbitrage on economic indicator and weather event contracts. These categories are Kalshi’s strongest suit — economic events like CPI releases, jobs reports, and Fed decisions generate substantial trading volume, and their outcomes also map to tradable instruments in other markets (CME FedWatch, traditional options, etc.).
What makes EventArb Pro interesting is its understanding of the relationship between Kalshi event contracts and traditional financial derivatives. A Kalshi contract on “Will CPI exceed 3.0% in March?” can be compared not just to a Polymarket equivalent but to options strategies on inflation-linked instruments. This cross-asset perspective opens arb opportunities that pure prediction-market scanners miss entirely.
The $79/month tier covers economics events only with manual execution alerts. The $199/month tier adds weather events, auto-execution via Kalshi API, and integration with a broker API for the traditional market leg. The limitation is scope: if you want to arb sports, politics, or entertainment contracts on Kalshi, EventArb Pro does not cover those categories. It also requires more financial market knowledge to use effectively than the other tools on this list.
PredictEngine (Kalshi Module)
PredictEngine is the largest hosted prediction market bot platform, and its Kalshi module adds arb scanning to its existing multi-strategy toolkit. If you are already a PredictEngine user running sentiment or trend-following strategies on Polymarket, the Kalshi arb module is a natural extension.
The arb scanner within PredictEngine compares Kalshi prices against Polymarket in real time, with fee-adjusted profit calculations and configurable alert thresholds. Execution is supported on both platforms from the same interface. PredictEngine also offers a visual rule builder where you can combine arb signals with other conditions — for example, “only execute this arb if sentiment analysis also supports the Kalshi side of the trade.”
The practical value depends on whether you are using PredictEngine’s broader platform. As a standalone arb tool, it is overpriced at $149-299/month (you are paying for the full platform). The arb scanning itself is competent but not as deep as KalshiArb or as broad as CrossPlatform Agent. The Kalshi API integration was added in late 2025 and still has rough edges — RSA key setup requires manual configuration steps that are poorly documented. For existing PredictEngine users, though, it is the most convenient way to add Kalshi arb to their workflow.
RegArb
RegArb is an open-source Python framework for regulated market arbitrage, released under the MIT license. It provides the scaffolding for building a Kalshi arb bot: API wrappers for Kalshi and Polymarket, fee calculation modules, position sizing utilities, and a basic arb detection loop. You supply the strategy logic, hosting, and monitoring.
The code quality is solid — clean architecture, type-hinted Python, decent test coverage. The Kalshi integration supports REST API v2 with RSA-PSS authentication and handles order placement, cancellation, and portfolio queries. A contributed module adds WebSocket streaming for real-time book data. The community is small but technically strong, with an active Discord where contributors discuss improvements and share custom strategy modules.
The 3.6 rating reflects the reality that RegArb is a framework, not a product. You need meaningful Python development experience to turn it into a working arb bot. There is no GUI, no hosted option, and no support team. Setup involves generating RSA keys, configuring API credentials, deploying to a server, and writing your own alert/execution logic. For developers comfortable with that, RegArb offers full control and zero recurring costs. For everyone else, it is a starting point for a custom build rather than a usable tool.
How to Evaluate Before Buying
Before committing to any Kalshi arb bot, run through this testing checklist:
- Demo environment test. Connect the bot to Kalshi’s demo API (demo-api.kalshi.co) and verify it can authenticate, pull market data, and place/cancel orders. If the bot cannot connect to demo, it will not work in production.
- Fee accuracy check. Pick a known arb opportunity (or simulate one) and verify the bot’s profit calculation matches your manual calculation after Kalshi fees. Off-by-one errors in fee calculation are common and can turn profitable arbs into losses.
- Cross-platform mapping review. Check 10-15 contract pairs the bot identifies as equivalent across platforms. Are the event descriptions genuinely the same? Do the settlement conditions match? Mismatched contracts create fake arb signals.
- Execution latency test. Measure the time from arb detection to order placement on Kalshi’s demo environment. Anything over 5 seconds is concerning for real arb trading.
- Position limit handling. Verify the bot respects Kalshi’s position limits and does not attempt to place orders exceeding them. A bot that gets rejected by Kalshi’s limit checks repeatedly will trigger rate limiting or account flags.
- Historical backtest. If the tool offers backtesting, run it against a period you have independent data for and compare results. Inflated backtest numbers are a common sales tactic.
- Paper trade for one week. Run the bot with alerting but no auto-execution for at least a week. Track every alert and verify manually whether the arb was real and executable.
Setup Guide: Getting Started with Kalshi Arbitrage
Here is the general process for setting up any Kalshi arb bot. Specific steps vary by tool, but the sequence is the same.
Step 1: Create and verify your Kalshi account. Go to kalshi.com and complete the registration process. You will need to provide personal identification documents for KYC verification. This is a CFTC requirement — there is no way around it. U.S. residency is required. Verification typically takes 1-3 business days.
Step 2: Enable API access and generate RSA keys. In your Kalshi account settings, enable API access. Generate an RSA key pair — Kalshi uses RSA-PSS signatures for API authentication, which is different from most crypto platform APIs. Store your private key securely. See the Kalshi API guide for step-by-step key generation instructions.
Step 3: Start with the demo environment. Configure your arb bot to connect to demo-api.kalshi.co using your demo API credentials (separate from production). Run test trades, verify order flow, and familiarize yourself with the bot’s interface and settings. Every tool on this list supports the demo environment.
Step 4: Configure cross-platform data sources. If your arb strategy involves comparing Kalshi prices to other platforms, set up the necessary API connections. For Polymarket, you will need a wallet and API credentials. For PredictIt, their API is public for market data. For traditional financial data, you may need a broker API or data vendor subscription.
Step 5: Set conservative initial parameters. Configure your arb threshold above the minimum (we recommend starting at 3% net profit or higher), set position sizes well below Kalshi’s limits, and keep auto-execution disabled initially. Run in alert-only mode for at least a few days before enabling auto-execution.
Step 6: Monitor and adjust. Track hit rate (what percentage of alerts are real, executable arbs), execution fill rate, and net profit after all fees. Gradually tighten your threshold and increase position sizes as you gain confidence in the bot’s accuracy.
For a complete walkthrough of evaluating and purchasing prediction market bots, see the buyer’s guide. For overall bot rankings beyond arbitrage, see best prediction market bots. For verification standards, see the bot verification guide.
Frequently Asked Questions
Can you legally run an arbitrage bot on Kalshi?
Yes. Kalshi explicitly supports algorithmic and automated trading through its REST API, WebSocket, and FIX 4.4 protocol. Arbitrage is a legitimate trading strategy. However, your bot must comply with Kalshi’s trading rules and position limits, and you need a verified U.S.-based account with KYC completed.
Where do Kalshi arbitrage opportunities come from?
Most Kalshi arb opportunities arise from pricing discrepancies between Kalshi event contracts and equivalent markets on other platforms like Polymarket, PredictIt, or even traditional derivatives. Intra-Kalshi arbs exist too — related contracts within the same event series can temporarily misprice relative to each other.
How much capital do I need to run a Kalshi arb bot?
Most arb opportunities on Kalshi carry margins of 1-4%. With typical margins that thin, you need meaningful capital to generate worthwhile returns. A starting bankroll of $2,000-5,000 is practical for testing; serious operators typically deploy $10,000 or more. Factor in that capital is locked until contract settlement.
Do arb bots work on Kalshi’s demo environment?
Partially. Kalshi’s demo sandbox (demo-api.kalshi.co) lets you test API connectivity, order placement, and bot logic with fake money. However, demo market prices do not perfectly mirror production, so real arb detection requires live data. Most serious arb bots test execution logic in demo and price scanning against production data.
Browse more agents in the marketplace, or read the complete marketplace guide for the full ecosystem overview.