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Buy both sides. The outcome doesn’t matter.

Two venues list the same question and price it independently. When they disagree enough, you can buy both sides for less than a dollar and collect a dollar whichever way the contract resolves. A hedge is only guaranteed once both legs fill. The Basis platform runs agents that find those gaps and take them. Twenty-four hours a day. Seven days a week.

Funds stay in your own venue accountsTrade keys only, never withdrawal keys
Priced on two venues, liveKalshiPolymarket
Will the Fed cut rates at the September meeting?
FED-SEP-CUT · resolves 18 Sep
KalsYES
52.1¢·
buys $1.00 if they cut
PolyNO
46.0¢·
buys $1.00 if they hold
·0.0¢
The pair costs
98.1¢ → pays $1.00
Gap
1.9¢
+1.94%
Kalshi YESPolymarket YESArbitrage available
62¢56¢51¢45¢
The shaded band is the gap. Basis takes it whenever it is wide enough to clear fees.

$392.40 in, $400 out — no matter what the Fed did. Basis never had a view on the rate decision — it only priced the gap between the two venues.

FED-SEP-CUTKAL/POLY+1.94%14:22CPI-JUL-28POLY/KAL+1.12%14:19SHUTDOWN-OCTKAL/POLY+2.40%14:17BTC-80K-AUGPOLY/KAL+0.86%14:14NYC-MAYOR-26KAL/POLY+1.61%14:11UNRATE-AUGPOLY/KAL+1.28%14:08ETH-4K-SEPKAL/POLY+2.02%14:04AAPL-FOLD-26POLY/KAL+0.94%14:01FED-SEP-CUTKAL/POLY+1.94%13:58CPI-JUL-28POLY/KAL+1.12%13:55SHUTDOWN-OCTKAL/POLY+2.40%13:51BTC-80K-AUGPOLY/KAL+0.86%13:47NYC-MAYOR-26KAL/POLY+1.61%13:44UNRATE-AUGPOLY/KAL+1.28%13:40ETH-4K-SEPKAL/POLY+2.02%13:36AAPL-FOLD-26POLY/KAL+0.94%13:32
Trading

Put in $2,500. Two weeks later it is $3,213.

A new agent on default settings, replayed against 26 July – 9 August 2026. Drag how much you put in and the fortnight rescales with it. Figures are gross of fees, and past replays are not a forecast.

You put in$2,500
$250$5,000$10,000
Worth after two weeks
$3,213.25
26 Jul – 9 Aug 2026, replayed
Realised
+$713.25
+28.53% across 34 settled hedges
Fills
349
63% Kalshi, 37% Polymarket
Average per hedge
+$20.98
Realised, over the 34 that settled
One of those 34 hedges, opened and settled on 4 AugustThe Twins won. Both columns pay the same, which is the point.
Will the Twins beat the Royals on 4 August?SportsMLB-MIN-KC-0804resolves 4 Aug04 Aug 12:30
$374.36Locked+$7.64
VenueBetSharesPriceCostPays
KalshiYESpays if it happens38254¢$206.28+$382.00
PolymarketNOpays if it does not38244¢$168.08$0.00
Position cost$374.36
If YES · actual+$7.64
If NO+$7.64
Guaranteed floor+$7.64+2.04%

This hedge costs $374.36 and floors at +$7.64. A hedge is only guaranteed once both legs fill — until the second fill lands you are holding one side alone, and on this position that leg is −$206 of exposure. Thirty-four of these over the fortnight is where the +$713.25 came from.

Screens

Build it on desktop. Watch it from your pocket.

Both screens below are running the same paper simulation right now: two weeks of real market data replayed at 4,032×, then live off the socket.

basis.green/agents/meridian
Your agents
Market
All hedges
Leaderboards
Wallets
Settings
Meridian· cross-venue arbitrage41 hedges openPaper
Live paper28 Jul 14:224,032×
Fills96
Locked floor+$228.40
$2,617.66+$114.69 (+4.58%)paper equity, past 2 weeksLIVE
TimeVenueContractSharesPriceCost
14:17PolyNOWill Ethereum flip $4,000 before September?12542¢$52.50
14:12KalsYESWill unemployment stay under 4.5% in August?7534¢$25.50
14:07PolyYESWill there be a government shutdown before 1 October?25037¢+$3.92
14:02KalsNOWill Bitcoin close above $80,000 on 31 August?30041¢$123.00
13:57PolyNOWill CPI come in below 2.8% for July?17548¢$84.00
13:52KalsYESWill the Fed cut rates at the September meeting?20045¢+$5.38
Desktop — build an agent, replay it, audit every leg.
9:41
Your floorLive
+$360.40
Worst case across all three agents, 64 open hedges. Meridian alone is +$228.40.
Your agents
Meridiancross-venue arbitrage+$228.40
Atlasgap sweep+$74.10
Kestrelsettlement carry+$57.90
HomeAgentsBoardsYou
Mobile — check the floor, pause an agent.
Ask Basis

Say what you want. Basis writes the settings.

Ask Basis reads your agents, your limits and your fill history. It drafts the change, explains what it costs you, and stops. Nothing reaches a venue until you approve the diff.

Agents can never withdraw money on their own.
Ask BasisReading Meridian
Pick one of the three questions below and watch Basis draft the change.
Try one
Ask about an agent, a limit or a skipped fill
MEMeridiancross-venue arbitrageDraft
EngineCross-venue arbitrage
MarketsMacro · Politics
Risk temperamentBalanced · 4 of 5
Max per hedge$2,500
Minimum edge0.4%
Slippage ceiling
Exposed legsAllow ≤ 1
Partial fillsCancel the pair
Daily cap$12,000
Auto-revertNone
These are the live settings on a paper agent. Ask a question on the left and the diff lands here.
Simulator

Every agent starts in the simulator.

The simulator runs a new agent against the last two weeks of real market data at 4,032×, catches up to now, then keeps paper trading live off the socket. Below is that screen with the chrome stripped out.

Nav
LIVE PAPER28 Jul 14:224,032×
01 · Equity, drawing as it replays
$2,617.66+$114.69 (+4.58%)paper equityLIVE
02 · Locked floor
+$228.40

Worst case across every open hedge. It only rises while positions stay locked, and it is nothing until both legs fill.

03 · Fills, streaming off the socket
TimeVenueContractSharesPriceCost
14:17PolyNOWill Ethereum flip $4,000 before September?12542¢$52.50
14:12KalsYESWill unemployment stay under 4.5% in August?7534¢$25.50
14:07PolyYESWill there be a government shutdown before 1 October?25037¢+$3.92
14:02KalsNOWill Bitcoin close above $80,000 on 31 August?30041¢$123.00
13:57PolyNOWill CPI come in below 2.8% for July?17548¢$84.00
01

Two weeks of real market data, replayed at 4,032×, then the agent catches up to now and keeps going live.

02

The floor is the worst case if every open hedge settles against you. It reads nothing until both legs of a hedge fill.

03

Every fill is logged with its venue, side, price and the agent that placed it, so any hedge can be audited later.

Portfolio

One view for every agent, both venues.

Liveupdated 28 Jul 14:22
Account equity
+4.58%
$2,617.66+$114.69 (+4.58%)past 2 weeksLIVE
Fills, as they land
STREAMING
TimeContractPriceCost
14:17Will Ethereum flip $4,000 before September?NOPoly12542¢$52.50
14:12Will unemployment stay under 4.5% in August?YESKals7534¢$25.50
14:07Will there be a government shutdown before 1 October?YESPoly25037¢+$3.92
14:02Will Bitcoin close above $80,000 on 31 August?NOKals30041¢$123.00
Working
$8,420.00
Across 41 open hedges
Realised
+$402.86
318 settled, 26 Jul – 9 Aug
Unhedged right now
$1,376.00
Four hedges still one leg short
Guaranteed floor
+$228.40
If every open hedge settles against you
Capital by market
Macro16$3,12037%
Politics11$2,48029%
Crypto8$1,56019%
Sports4$84010%
Tech2$4205%
Where it sits
$8,420working
Kalshi$4,890Polymarket$3,530

Balances are read from your own venue accounts. Basis never pools them.

Banked against working
Equity$10260.00
Banked$1840.00never staked again
Working$8420.00in play right now

Sweeps 25% of each win into the vault every 10 settled hedges. Four to go. Banked capital stops working, and stops being at risk.

Your agents against each other
Hover any point to read all three at once
26 Jul – 9 AugHover to compare
MeridianAtlasKestrel
The spread Meridian is watching
62¢56¢51¢45¢

Shaded wherever the two venues disagree enough to cover both legs and the fee.

ATL @ NYMSportsReplay the buildbefore the first set
Floor
Blended
Hedged
Exposure
no fills yet100¢ — break-even
a set that matched — lower on the plot is a better price for the pairone leg landed aloneengine sold a lone leg backblended cost so far
19:05Z · 8 Aug0 of 8 sets · 0 matched · 0 naked open20:37Z · 8 Aug
Agent record
26 Jul – 9 Aug 2026
AgentStrategyHedgesLockedWent exposedFloorRealised
Meridiancross-venue arbitrage1181144+$96.40+$174.62
Atlasgap sweep76688+$74.10+$131.98
Kestrelsettlement carry1241213+$57.90+$96.26
Open hedges
4 of 41
ContractCostEdgeFloor
Will CPI come in below 2.8% for July?MacroCPI-JUL-28resolves 12 Aug09 Aug 09:14
$416.50+2.04%+$8.50
Will there be a government shutdown before 1 October?PoliticsSHUTDOWN-OCTresolves 1 Oct09 Aug 08:41
$294.00+2.04%+$6.00
Will Bitcoin close above $80,000 on 31 August?CryptoBTC-80K-AUGresolves 31 Aug09 Aug 07:58
$250.000.00%$0.00
Will the Twins beat the Royals on 11 August?SportsMLB-MIN-KC-0811resolves 11 Aug09 Aug 07:22
$139.50-35.48%−$49.50up to +$40.50
Contracts you are in
Will CPI come in below 2.8% for July?CPI-JUL-28resolves 12 Aug$1.2M vol
Will there be a government shutdown before 1 October?SHUTDOWN-OCTresolves 1 Oct$840K vol
Will Bitcoin close above $80,000 on 31 August?BTC-80K-AUGresolves 31 Aug$2.4M vol
Will unemployment stay under 4.5% in August?UNRATE-AUGresolves 6 Sep$610K vol
How the 41 are sitting
+1.94%Both legs filled. These carry the floor.31
+0.20%Floor within a cent of zero.6
FillingOne leg still filling.4

Only the locked ones carry a floor. A hedge is only guaranteed once both legs fill, so the four filling hedges count for nothing until they do.

Security

Basis cannot move your money.

Every fill happens inside accounts you own. Basis places and cancels orders within the limits you set — that is the whole permission set, on both venues.

Both venues
Trade keys only, never withdrawal keys

Basis holds no balance and has no path to one. It can place and cancel orders inside your limits; moving money out of either account is something only you can start, from the venue itself.

Kalshi
A subaccount and an API key per agent

Each agent trades in its own Kalshi subaccount under its own key, scoped to trading. You fund a subaccount to give an agent room, and revoking one key stops that agent without touching the others.

Polymarket
Import your wallet, or export ours

Bring a wallet you already control, or export the one Basis creates for you at any time — the keys are yours either way. Single-wallet safeguards cap what one transaction can spend, so a bad instruction cannot drain it.

Apply for an account.

Basis is invite-only while the live venue integrations are in review. Tell us where you already trade and we will come back within two business days. Applying connects nothing — you add venue keys later, and only trade keys.

Paper trading from the first day, on two weeks of replayed market dataFunds stay in your own Kalshi and Polymarket accountsTrade keys only. Basis cannot withdraw, and cannot move funds between venues
Request access

Basis is not a broker and does not hold your funds. Event contracts on Kalshi and Polymarket can resolve against an unhedged leg; you can lose money.