Best Arbitrage Bot for Polymarket 2026: Top Picks Reviewed

Arbitrage on prediction markets is conceptually simple: find two prices that disagree, buy low, sell high, and pocket the difference. On Polymarket specifically, arb opportunities emerge when correlated markets drift apart, when YES and NO shares misprice relative to $1.00, or when Polymarket’s odds diverge from the same event on Kalshi or other platforms.

The execution, however, is anything but simple. Spreads are thin, competition from other bots is fierce, and a slow arb scanner can consistently arrive after the opportunity has already closed. The right bot needs to be fast, accurate at identifying genuine mispricings (not just noise), and reliable enough to execute both legs of a trade before the spread disappears.

This guide reviews the five best arbitrage bots and tools available for Polymarket in 2026, with honest assessments of where each one excels and where it falls short.

For broader context on the prediction market bot ecosystem, see the overall bot rankings and the buyer’s guide.

What to Look for in an Arbitrage Bot

Not all arb bots are created equal. Before evaluating specific products, here are the criteria that matter most:

1. Detection speed and accuracy. The bot needs to identify genuine arbitrage opportunities quickly — ideally within seconds of a spread opening. False positives (flagging normal price movement as arb) waste capital and erode trust. The best bots use multiple confirmation signals before triggering a trade.

2. Execution reliability. Finding an arb is only half the job. The bot must execute both legs of the trade before the spread closes. This means tight integration with Polymarket’s CLOB API, proper order management, and graceful handling of partial fills or failed transactions. A bot that detects arbs but fails to execute them is worse than useless — it gives you false confidence.

3. Cross-platform reach. Intra-Polymarket arbs still exist, but the most consistent spreads in 2026 are between platforms. Bots that scan Polymarket, Kalshi, and other prediction markets simultaneously find more opportunities and wider spreads. If a bot only looks at Polymarket, it is competing in the most crowded lane.

4. Risk management. Good arb bots let you set maximum position sizes, stop trading when spreads narrow below a threshold, and alert you when one leg of a trade fails. Without these controls, a bot can accumulate large one-sided positions during volatile markets.

5. Fee awareness. Arbitrage profits are often small — sometimes just 1-3 cents per share. A bot that does not factor in Polymarket’s trading fees, gas costs, and potential slippage will report profitable arbs that actually lose money after costs. Fee-adjusted scanning is non-negotiable.

Top Picks: Arbitrage Bots for Polymarket 2026

Detailed Reviews

PolyArb Pro

PolyArb Pro is the most polished arbitrage bot available for Polymarket in 2026. It runs as a hosted SaaS product — you connect your Polymarket wallet, configure your risk parameters through a web dashboard, and the bot handles scanning, execution, and reporting.

The scanning engine covers both intra-Polymarket opportunities (correlated markets, YES/NO mispricing) and cross-platform arbs between Polymarket and Kalshi. Detection latency is typically under two seconds for intra-market opportunities and under five seconds for cross-platform scans. In our testing, roughly 70% of flagged opportunities were still available by the time execution started — a solid hit rate given how competitive arb scanning has become.

Where PolyArb Pro stands out is execution reliability. It uses Polymarket’s CLOB API directly with optimized order routing, handles partial fills gracefully, and automatically unwinds positions if one leg fails. The dashboard shows real-time PnL (profit and loss) with fee-adjusted reporting, so you know exactly what you are netting after costs. The main drawback is price: at $149-399/month depending on tier, you need meaningful capital deployed to justify the subscription. The $149 tier limits you to intra-Polymarket arbs; cross-platform scanning requires the $249+ tier.

PolyArb Pro is the right choice if you are treating Polymarket arbitrage as a serious, ongoing operation with $3,000+ in capital. For casual traders or those just experimenting, the cost is hard to justify.

ArbScanner

ArbScanner takes a different approach: it focuses on detection and alerting rather than full execution. The core product is an arb scanner that monitors Polymarket markets and sends you alerts (via Telegram, Discord, or webhook) when it identifies a spread above your configured threshold. An auto-execution mode exists but is limited to intra-Polymarket trades on the higher tier.

The alert-only approach has a real advantage: lower risk. You review each opportunity before committing capital, which avoids the “bot went haywire at 3 AM” scenario. The scanner covers Polymarket comprehensively and includes basic Kalshi cross-referencing on the $199/month plan. Detection speed is solid — most alerts arrive within 3-5 seconds of a spread opening, though this is noticeably slower than PolyArb Pro.

The execution module, available on the $199 tier, handles straightforward intra-market arbs but lacks the sophistication of PolyArb Pro’s order management. Partial fills and failed legs require manual intervention more often than they should. ArbScanner is best suited for traders who want to stay in the loop on arb opportunities without handing full control to a bot. At $79/month for alert-only mode, it is the most affordable entry point for systematic arb scanning on Polymarket.

CrossMarket Agent

CrossMarket Agent is a developer SDK, not a hosted product. You install it as a Python package, configure API connections to Polymarket (and optionally Kalshi, Metaculus, and other platforms), and it handles the scanning and execution logic while running on your own infrastructure.

The key differentiator is cross-platform depth. While PolyArb Pro and ArbScanner treat cross-platform arb as an add-on, CrossMarket Agent was built for it from the ground up. It normalizes market data across platforms, handles the different settlement mechanics, and accounts for platform-specific fee structures when calculating net arb profitability. The matching algorithm is notably good at identifying semantically equivalent markets across platforms, even when the market titles differ.

Setup requires meaningful Python experience and your own server or cloud instance. Documentation is thorough but assumes developer-level knowledge. The $500 one-time price includes six months of updates; after that, continued updates are $100/year. There is no hosted option — if you cannot run a Python service, this is not for you. For developers who want maximum control over their arb strategy and cross-platform reach, CrossMarket Agent is the strongest option. For the technical foundations, see the Polymarket API guide and the unified API comparison.

SpreadHunter

SpreadHunter is a self-hosted arb bot written in TypeScript/Node.js. It focuses exclusively on intra-Polymarket arbitrage — finding mispricings between correlated markets within the Polymarket ecosystem. It does not scan other platforms.

The narrow focus has an upside: SpreadHunter is fast and specialized. It uses Polymarket’s WebSocket feed for real-time price updates and can detect and execute arbs in under one second in optimal conditions. The correlation engine that identifies related markets is configurable, letting you define your own market pairs or use the built-in heuristics. For pure intra-Polymarket arb, it is the fastest option available.

The downsides are meaningful. No cross-platform support means you are competing in the most crowded segment of arb trading. The TypeScript codebase is well-structured but lightly documented — expect to read source code. And the lack of a web dashboard means monitoring happens through logs and CLI output. SpreadHunter suits technical traders who believe intra-Polymarket spreads still offer enough opportunity to justify the focused approach and who are comfortable working in a terminal.

OctoBot (Arb Module)

OctoBot is an open-source trading bot framework that has been around since the crypto trading era. Its prediction market support is relatively new, added through a Polymarket plugin, and the arb module is one of several strategy types it supports. If you are already running OctoBot for other purposes, adding the arb module is straightforward.

The arb module scans for intra-Polymarket opportunities and can be configured to alert or auto-execute. It benefits from OctoBot’s mature infrastructure — web dashboard, backtesting engine, portfolio tracking — but the Polymarket integration itself is less polished than purpose-built arb bots. Detection speed is adequate but not competitive with PolyArb Pro or SpreadHunter, and cross-platform arb is not yet supported.

OctoBot’s arb module is best viewed as a “good enough” option for existing OctoBot users or for traders who want to experiment with arb strategies within a broader bot framework. For dedicated arb trading on Polymarket, the purpose-built options above are significantly better. The open-source core is free; the premium tier ($99/month) adds hosted infrastructure and priority support. For more on OctoBot’s broader capabilities, see the overall bot rankings.

How to Evaluate Before Buying

Before committing to any arb bot, run through this testing checklist:

• Paper trade for at least two weeks. Every bot on this list offers either a trial period or a paper trading mode. Use it. Arb bot performance varies significantly depending on market conditions, and two weeks gives you a reasonable sample.
• Verify fee-adjusted returns. Ask the bot to show net returns after Polymarket fees, gas costs, and any slippage. If the dashboard only shows gross arb spread captured, do the math yourself — you may find that many “profitable” arbs are break-even or negative after costs.
• Test failure handling. Deliberately trigger edge cases: what happens when one leg of an arb fails? Does the bot unwind the other leg, hold, or do nothing? Poor failure handling is the single biggest risk in arb trading.
• Check execution speed against competition. During your trial, track how many flagged opportunities are still available when the bot tries to execute. If fewer than 50% of arbs are capturable, the bot is too slow for the current competitive environment.
• Review the support and update cadence. Polymarket’s API and fee structure change. A bot that was last updated three months ago may be using stale fee calculations or broken API endpoints. Check the changelog or commit history.
• Compare against manual arb scanning. Spend a few hours manually scanning Polymarket for arbs alongside the bot. This gives you ground truth for whether the bot is finding opportunities you would miss, or just flagging the same obvious spreads you can see yourself.

For a deeper framework on evaluating prediction market agents, see the verification guide and the buyer’s guide.

Setup Guide: Getting Started with Arb Trading on Polymarket

If you have selected a bot, here is the general sequence to go from zero to live arb trading:

Step 1: Set up your Polymarket account and wallet. You need a funded Polymarket wallet with USDC on Polygon. If you are using cross-platform arb, you will also need funded accounts on the other platforms. See the Polymarket bot quickstart for wallet setup details.

Step 2: Generate API credentials. Polymarket’s CLOB API requires API keys for programmatic trading. Generate these through the Polymarket interface and store them securely. For guidance on API setup, see the Polymarket API guide.

Step 3: Connect the bot. For hosted bots (PolyArb Pro, ArbScanner), enter your API credentials in the bot’s dashboard. For self-hosted bots (CrossMarket Agent, SpreadHunter, OctoBot), configure the credentials in your local environment file. Never share API keys or commit them to version control.

Step 4: Configure risk parameters. Set your maximum position size per arb, minimum spread threshold (we recommend starting at 3 cents or higher to ensure fee-adjusted profitability), maximum concurrent positions, and daily loss limit. Start conservative — you can always loosen parameters after you have confidence in the bot’s behavior.

Step 5: Run in paper/alert mode first. Every bot listed above supports either paper trading or alert-only mode. Use this for at least one to two weeks to validate detection accuracy and execution reliability before risking real capital.

Step 6: Go live with small size. When you are ready to trade live, start with 10-20% of your intended capital. Monitor closely for the first few days, checking that fee-adjusted PnL matches what you saw in paper trading. Scale up gradually as you build confidence.

Step 7: Monitor and iterate. Arb opportunities shift as markets mature and competition changes. Review your bot’s performance weekly, adjust spread thresholds as needed, and stay current on Polymarket API changes that might affect execution.

What to Read Next

• Best Prediction Market Bots 2026 — overall rankings across all strategies
• How to Buy a Prediction Market Agent — full buyer evaluation framework
• Bot Verification Guide — how to verify agent performance claims
• Polymarket Bot Ecosystem — all tools and bots for Polymarket
• Cross-Market Arbitrage Guide — deep dive on cross-platform arb strategies
• Browse the Agent Marketplace — find and compare agents directly