Limitless and Polymarket Arbitrage (2026)
The Short Answer
Limitless and Polymarket list many of the same events at independently set prices, so gaps between them appear constantly. Turning a gap into a trade is harder here than on a regulated venue pair, because both are onchain and they settle on different chains: Limitless on Base, Polymarket on Polygon. That means two wallets, two gas tokens, two signatures, and collateral that cannot move directly from one leg to the other. A displayed gap is an indicative price discrepancy until it has been checked against live asks with size, both fee schedules, gas on both chains, and whether the two contracts resolve on the same criteria.
Key Takeaways
- Both venues are onchain but on different chains, so every position needs native gas on Base and on Polygon separately.
- Limitless reads are fully public: markets, order books and price history need no API key, which makes the discovery half cheap to build.
- Writing an order on Limitless takes two credentials, an HMAC signature to authenticate the request and an EIP-712 signature to authorize the trade.
- Collateral does not move between the two venues. Each is funded on its own chain, and rebalancing means a bridge and a wait.
- The gap you can see on midpoints is not the gap you can trade. Depth at the ask decides that, and it is usually thinner than the top of book suggests.
- Resolution equivalence is the risk nobody prices. Two contracts describing the same event can settle differently on an edge case.
Can you arbitrage between Limitless and Polymarket?
The opportunity is real in the sense that the prices genuinely diverge. Two independent order books, two different sets of traders, no mechanism forcing them to agree. On any busy event you will see the same outcome quoted a few cents apart, sometimes more.
What makes this pair different from the comparisons people usually write about is that both venues are onchain. A Kalshi and Polymarket pair is a regulated dollar account against a crypto wallet, and most of the friction is in access and custody. Limitless against Polymarket is two crypto-native venues, which sounds simpler and is not, because they live on different chains.
Limitless settles on Base. Polymarket settles on Polygon. Everything awkward about this pair follows from that one fact.
Why do the prices differ in the first place?
Three reasons, and it helps to know which one you are looking at.
Different traders. The two venues have different user bases with different information and different appetites. Neither book is a mirror of the other, and a genuine difference of opinion is not an error to be corrected.
Different liquidity. A price backed by a few hundred dollars will drift further from fair value than one backed by tens of thousands. Much of what looks like a pricing gap is one venue having a thin book on that particular market.
Different contract wording. This is the one that gets mistaken for the other two. If the gap looks too wide, read both rulebooks before assuming the market is wrong. Sometimes the contracts are not describing the same thing, and the price difference is correct.
What does it actually cost to trade both legs?
Four costs, and the ones people forget are the last two.
| Cost | Where it lands |
|---|---|
| Venue fees | Each venue publishes its own schedule. Read both current pages rather than trusting a summary. |
| Spread | You cross it on both legs. Two half-spreads is a real cost, not a rounding error. |
| Gas on Base | Approval and order for the Limitless leg. |
| Gas on Polygon | Approval and order for the Polymarket leg, paid in that chain's native token. |
Gas is the part that turns small edges negative. You need the native gas token on both chains before you start, and topping one up while a gap is open means you have already missed it. Fund both sides in advance or the position is not available to you.
There is a subtler version of this. If you need to rebalance, moving collateral from Base to Polygon is a bridge, and a bridge takes time and costs gas on both ends. Each venue is effectively its own island: funds leave by that venue's own rails, and nothing moves sideways between them instantly. So the capital you want on each side has to be sitting there already.
How do you find the gaps programmatically?
The discovery half is cheaper than people expect, because Limitless publishes its read surface openly.
The Limitless REST API lives at https://api.limitless.exchange with a websocket at wss://ws.limitless.exchange. Markets, search, order books, price history and public portfolio lookups all come back without credentials. You only need a key when you start writing orders.
Polymarket's CLOB API is similarly open for reads. So a scanner that watches both books is two clients and a matching problem.
The matching problem is the hard part, and it is worth being honest about why. There is no shared identifier for a real world event. The same election or match appears on one venue with one slug and one title, and on the other with a different slug and a title written differently. Before comparing two prices you have to establish the two contracts are the same contract, and there is no authority to ask.
The alternative to building that yourself is reading both venues through one normalized schema. Predictefy serves Limitless and Polymarket as two of 16 venues on a single contract, so the same request shape works for both and the cross-venue matching is already done:
curl -s "https://data.predictefy.com/api/router/fetchArbitrage?contracts=100&limit=50&executableOnly=true" \
-H "Authorization: Bearer pk_live_YOUR_KEY"fetchArbitrage is router-only, because a cross-venue question needs every venue at once. contracts is the size you actually intend to trade, which matters: a gap that clears at 10 contracts often does not clear at 500. executableOnly=true filters to rows that passed the live checks rather than rows that merely look good on midpoints.
What makes a gap executable rather than just visible?
This is the distinction that separates a scanner from a strategy.
A gap computed from midpoints tells you the two venues disagree. It does not tell you that you can trade it. To become executable a row has to pass every one of these:
- Live asks with size. Not the midpoint, not the top of book alone. The actual depth available at the price you would pay, for the quantity you want.
- Both markets open. A closed or halted leg turns a hedge into a naked position.
- Fees and gas on both legs. Including the native gas on each chain.
- Resolution equivalence. The two rulebooks have to settle the same way in every scenario, not just the obvious one.
A well-built assessment fails closed. When a gate cannot be evaluated, the row stays labeled indicative and carries the reason it was not upgraded. That matters more than it sounds, because "we could not verify this" and "we verified there is no edge" are completely different answers, and a system that collapses them into one is telling you something it does not know.
What can go wrong between placing the two legs?
One leg fills and the other does not. You are now directionally exposed on an event you were trying to be neutral on. On a two-chain pair this risk is larger, because the legs cannot be submitted atomically and confirmation times differ between Base and Polygon.
The price moves while you are signing. Both venues need a wallet signature per order. That is seconds of latency during which the book can move, and the gap you priced may not be the gap you get.
Partial fills. Getting 200 of 500 contracts on one leg and all 500 on the other leaves you hedged on 200 and exposed on 300.
The contracts resolve differently. The worst outcome and the least discussed. If an edge case arrives and the two rulebooks disagree, you do not have a hedge. You have two losing positions that were supposed to cancel out. Read both resolution criteria before the trade, specifically hunting for the scenario where they would diverge.
Frequently Asked Questions
Is arbitrage between Limitless and Polymarket allowed?
Neither venue prohibits trading the same event on another platform, and taking both sides is ordinary market activity. Read each venue's terms for your own situation, and check your local rules on trading these products. Nothing here is legal, financial or tax advice.
Do I need two wallets for Limitless and Polymarket?
You need funded positions on both chains, since Limitless settles on Base and Polymarket on Polygon. The same wallet address can hold assets on both, but each chain needs its own native gas token and its own collateral balance before you can place either leg.
How much capital do you need to start?
Enough on both chains simultaneously, which is the constraint people underestimate. Because collateral cannot move between the venues quickly, capital sits idle on each side waiting for opportunities. Small accounts also suffer most from fixed gas costs, which do not shrink with position size.
Can you automate Limitless and Polymarket arbitrage?
Yes for discovery, which is straightforward since both venues publish open read APIs. Execution is harder: Limitless orders need an HMAC signature plus an EIP-712 wallet signature, and Polymarket has its own signing flow. Both legs are signed client side, so key custody stays in your process.
Why is the gap smaller than it looked?
Because midpoints are not tradable prices. The number shrinks once you use live asks with real size, subtract both venues' fees, and add gas on Base and Polygon. Thin books are the usual culprit, where a wide top of book hides very little depth behind it.