Kalshi vs Polymarket

Funding is signed. Positive means longs pay shorts, negative means longs get paid to hold. Venues settle on different native periods (hourly on Hyperliquid, dYdX, Lighter, Extended, Pacifica, Ondo, Vest, StandX and ApeX, every 4h on edgeX, every 8h on Kalshi, Aster and the CEX books); every figure is normalized from the venue's own quoted rate and interval before ranking. Funding is only the holding cost. Opening costs (taker fee, spread, impact) are the companion bench perp-fees.

Ramp tiers stay well inside documented budgets where they exist, at most 7 percent of Polymarket's published book allowance, and every run aborts at the first sign of sustained errors. This benchmark measures throttle onset behaviour at polite request rates, not maximum venue throughput.

Uptime here means our probes succeeded from three specific regions at a polite request rate. A venue can be up for us and degraded for you, especially during regional network incidents, and a brief blip between probe cycles can go unrecorded. Treat the panel as a measured signal, not a guarantee.

Ranked only with 24 hours of funding history (288 samples) and a stddev above zero: a young listing, or a venue whose rate has not moved since listing (Ondo Perps at launch, Polymarket in July), reads artificially stable and shows as Provisional, never as the leader. Stability is not directionality: a persistently positive but tight band ranks above a rate that flips every settlement.

Connect-to-snapshot includes Cloudflare edge latency and routing from each probe region. Numbers vary with network conditions and market activity. This bench measures observed end-to-end startup time, not venue-side processing time alone.

The ratio is a screen, not a verdict. Both terms are the venue's own figures (24h volume and open interest as each API reports them, in USD), so a venue that counts both legs of a fill moves its ratio without changing anything real. A very low ratio (Ostium, 0.2x) means positions held for days on thin daily volume; a very high one (Kalshi, above 40x) means a day of trading dwarfs what stays open. The bands in the methodology say what each range usually means.

Every row is a month of funding at the venue's average daily cost over the hours measured in the trailing 30 days (average x 30). A venue ranks only with 576 of the 720 hours (24 days) behind that average; under the floor the row is provisional, unranked, and shows its day count (the venues added on 2026-09-22 and 2026-09-23 start there). Funding is signed: on a month where shorts paid longs the figure is negative and "cheapest" means "was paid the most".

Open interest is not measured the same way everywhere. Venues with a dedicated public API report it natively; the rest are read from DefiLlama's protocol TVL, which is the closest public proxy and is not the same thing. A CFTC-regulated exchange has no on-chain balance and therefore no row when its API does not publish one. Size here says where capital sits, not whether a venue is liquid or well run.