Machine-readable files behind the numbers on this site. Our fee schedule and availability files are published under CC BY 4.0. Market price files contain third-party data from Polymarket and Kalshi and are not licensed by PolyKal.
PolyKal (polykal.net) is a free, independent, read-only reference that compares publicly displayed prices, fee schedules and regional availability on Polymarket and Kalshi. Its fee schedule and availability files are published under CC BY 4.0, and every record carries a verification date. PolyKal has no accounts and no affiliate links, and is not affiliated with either platform.
Also listed on GitHub: github.com/bcptdtptp2011-cloud/polykal-data.
JSON — polykal.net/data/fees.json
What it contains: Each platform's published trading-fee formula and constants, per-category Polymarket taker rates, Kalshi series multipliers, the primary sources, and a changelog. A live_check block adds the most recent on-chain check of Polymarket fees (real taker fills compared with the formula).
Updates: Rebuilt every 15 minutes. The rates themselves change only when a platform changes its schedule; every such change is a dated entry in the file's changelog. The on-chain check runs once a day.
Verification: Kalshi verified on 2026-09-12, Polymarket on 2026-09-20, each against its primary source. The top-level verified_on is the older of the two.
Shown on: polykal.net/fee-schedule/
Example citation: PolyKal (polykal.net), “Kalshi and Polymarket fee schedules”, verified 2026-09-12, https://polykal.net/data/fees.json. CC BY 4.0.
JSON — polykal.net/data/availability.json
What it contains: For 28 countries and territories: what each platform's own restriction documents say, plus public regulator and court actions. Every action carries a source tier (official, platform or secondary) and the date we checked it. Not legal advice.
Updates: Checked by hand. Each entry carries its own check date; a full re-check is scheduled for 2026-12-24.
Verification: Last updated 2026-09-27. Dates are per entry and per action.
Shown on: polykal.net/availability/
Example citation: PolyKal (polykal.net), “Polymarket and Kalshi regional availability”, updated 2026-09-27, https://polykal.net/data/availability.json. CC BY 4.0.
JSON — polykal.net/data/midterms-2026.json · CSV — polykal.net/data/midterms-2026.csv
What it contains: One row per outcome (candidate, party or combination) in each race we track — Senate and governor races, chamber control and related markets — with both platforms' displayed probabilities side by side and the gap between them. The numbers are the same ones shown on the Midterms pages. It does not report election results.
Price basis: Polymarket: the displayed price. Kalshi: the midpoint of best bid and best ask when the spread is 8¢ or less, otherwise the best bid; the last trade only when there is no bid. Probabilities are rounded as displayed on polykal.net (one decimal of a percent) and written as 0–1. kalshi_volume_contracts is a number of contracts, not US dollars.
Updates: Rebuilt every 15 minutes from five-minute price snapshots. Before results come in, the file freezes at the last snapshot before polls close (frozen and frozen_at in the header) and stops changing.
Verification: Each row says whether the two platforms' markets and rule text were checked by hand (verified = checked) or matched automatically (auto). data_as_of_utc is the time of the snapshot the row comes from.
Shown on: polykal.net/midterms/
Rows: One row per option; group by race_id for one row per race.
| Field | Meaning |
|---|---|
race_id | PolyKal race id (stable). |
state | |
office | senate | governor | control | related |
special_election | true for special elections (as named in the platforms' rules). |
polymarket_slug | |
kalshi_ticker | |
option | Outcome as matched across both platforms (candidate, party or combination). |
party | D / R / I where applicable, else empty. |
polymarket_prob | Polymarket displayed price (0–1), rounded as shown on polykal.net (one decimal of a percent). |
kalshi_prob | Kalshi price (0–1): midpoint of best bid and ask when the spread is 8¢ or less, otherwise best bid; last trade only if there is no bid. Rounded as shown on polykal.net. |
gap_pp | Absolute difference of the two displayed percentages, in percentage points. Empty when the two platforms' contracts are not directly comparable. |
polymarket_volume_usd | Polymarket 24-hour volume for the whole event, US dollars. |
kalshi_volume_contracts | Kalshi 24-hour volume for the whole event, in contracts (not US dollars). |
verified | checked = both markets and their rule text were checked by hand; auto = matched automatically. |
frozen | true after the pre-results freeze (last price captured before polls closed). This file does not report results. |
data_as_of_utc | Time of the snapshot these values come from (UTC). |
source_urls | Each platform's public market page, separated by a space. |
Example citation: PolyKal (polykal.net), “2026 U.S. midterm elections: Polymarket and Kalshi prices”, data as of 2026-10-13, https://polykal.net/data/midterms-2026.json.
A verification date is the day we last compared that record with its primary source (the platform’s own documentation, its public API, or the regulator or court document). It is not the date the platform last changed anything. Live prices carry the time of the snapshot instead.
The fee schedule (fees.json) and regional availability (availability.json) files are published under CC BY 4.0. You can copy, adapt and republish them, including commercially, as long as you credit “PolyKal (polykal.net)” and link to the file or page you used.
The midterm price files (midterms-2026.json and .csv) contain third-party market prices from Polymarket and Kalshi, shown for reference. These prices are not licensed by PolyKal. Methodology: /methodology/; sources: /data-sources/.
Found an error, or need a field we don’t publish? Email [email protected].
Machine-readable files behind the numbers on this site. Our fee schedule and availability files are published under CC BY 4.0. Market price files contain third-party data from Polymarket and Kalshi and are not licensed by PolyKal.
PolyKal (polykal.net) is a free, independent, read-only reference that compares publicly displayed prices, fee schedules and regional availability on Polymarket and Kalshi. Its fee schedule and availability files are published under CC BY 4.0, and every record carries a verification date. PolyKal has no accounts and no affiliate links, and is not affiliated with either platform.
Also listed on GitHub: github.com/bcptdtptp2011-cloud/polykal-data.
JSON — polykal.net/data/fees.json
What it contains: Each platform's published trading-fee formula and constants, per-category Polymarket taker rates, Kalshi series multipliers, the primary sources, and a changelog. A live_check block adds the most recent on-chain check of Polymarket fees (real taker fills compared with the formula).
Updates: Rebuilt every 15 minutes. The rates themselves change only when a platform changes its schedule; every such change is a dated entry in the file's changelog. The on-chain check runs once a day.
Verification: Kalshi verified on 2026-09-12, Polymarket on 2026-09-20, each against its primary source. The top-level verified_on is the older of the two.
Shown on: polykal.net/fee-schedule/
Example citation: PolyKal (polykal.net), “Kalshi and Polymarket fee schedules”, verified 2026-09-12, https://polykal.net/data/fees.json. CC BY 4.0.
JSON — polykal.net/data/availability.json
What it contains: For 28 countries and territories: what each platform's own restriction documents say, plus public regulator and court actions. Every action carries a source tier (official, platform or secondary) and the date we checked it. Not legal advice.
Updates: Checked by hand. Each entry carries its own check date; a full re-check is scheduled for 2026-12-24.
Verification: Last updated 2026-09-27. Dates are per entry and per action.
Shown on: polykal.net/availability/
Example citation: PolyKal (polykal.net), “Polymarket and Kalshi regional availability”, updated 2026-09-27, https://polykal.net/data/availability.json. CC BY 4.0.
JSON — polykal.net/data/midterms-2026.json · CSV — polykal.net/data/midterms-2026.csv
What it contains: One row per outcome (candidate, party or combination) in each race we track — Senate and governor races, chamber control and related markets — with both platforms' displayed probabilities side by side and the gap between them. The numbers are the same ones shown on the Midterms pages. It does not report election results.
Price basis: Polymarket: the displayed price. Kalshi: the midpoint of best bid and best ask when the spread is 8¢ or less, otherwise the best bid; the last trade only when there is no bid. Probabilities are rounded as displayed on polykal.net (one decimal of a percent) and written as 0–1. kalshi_volume_contracts is a number of contracts, not US dollars.
Updates: Rebuilt every 15 minutes from five-minute price snapshots. Before results come in, the file freezes at the last snapshot before polls close (frozen and frozen_at in the header) and stops changing.
Verification: Each row says whether the two platforms' markets and rule text were checked by hand (verified = checked) or matched automatically (auto). data_as_of_utc is the time of the snapshot the row comes from.
Shown on: polykal.net/midterms/
Rows: One row per option; group by race_id for one row per race.
| Field | Meaning |
|---|---|
race_id | PolyKal race id (stable). |
state | |
office | senate | governor | control | related |
special_election | true for special elections (as named in the platforms' rules). |
polymarket_slug | |
kalshi_ticker | |
option | Outcome as matched across both platforms (candidate, party or combination). |
party | D / R / I where applicable, else empty. |
polymarket_prob | Polymarket displayed price (0–1), rounded as shown on polykal.net (one decimal of a percent). |
kalshi_prob | Kalshi price (0–1): midpoint of best bid and ask when the spread is 8¢ or less, otherwise best bid; last trade only if there is no bid. Rounded as shown on polykal.net. |
gap_pp | Absolute difference of the two displayed percentages, in percentage points. Empty when the two platforms' contracts are not directly comparable. |
polymarket_volume_usd | Polymarket 24-hour volume for the whole event, US dollars. |
kalshi_volume_contracts | Kalshi 24-hour volume for the whole event, in contracts (not US dollars). |
verified | checked = both markets and their rule text were checked by hand; auto = matched automatically. |
frozen | true after the pre-results freeze (last price captured before polls closed). This file does not report results. |
data_as_of_utc | Time of the snapshot these values come from (UTC). |
source_urls | Each platform's public market page, separated by a space. |
Example citation: PolyKal (polykal.net), “2026 U.S. midterm elections: Polymarket and Kalshi prices”, data as of 2026-10-13, https://polykal.net/data/midterms-2026.json.
A verification date is the day we last compared that record with its primary source (the platform’s own documentation, its public API, or the regulator or court document). It is not the date the platform last changed anything. Live prices carry the time of the snapshot instead.
The fee schedule (fees.json) and regional availability (availability.json) files are published under CC BY 4.0. You can copy, adapt and republish them, including commercially, as long as you credit “PolyKal (polykal.net)” and link to the file or page you used.
The midterm price files (midterms-2026.json and .csv) contain third-party market prices from Polymarket and Kalshi, shown for reference. These prices are not licensed by PolyKal. Methodology: /methodology/; sources: /data-sources/.
Found an error, or need a field we don’t publish? Email [email protected].