Data Sources

Principles

• Public sources only. PolyKal reads what the two platforms publish through their public APIs and documents. It holds no trading account, places no orders and never asks for yours.
• Nothing is fabricated. When a source returns nothing, the page shows “No data”; when a source returns a record without a particular field, that field shows “—”. Design placeholders never survive into a published page.
• Every figure is a snapshot. Pages show the capture time (“Data as of … ET”) and how it was obtained. Nothing on the site is a live exchange feed.
• Platform data stays in the platform's own terms. Market titles, outcome names and usernames are shown as published; PolyKal does not translate or rename them.

Sources by page

Time zones and timestamps

All times on the site are shown in US Eastern Time (ET) and labelled as such. Build-time figures carry the moment the page was generated; browser-fetched figures carry the moment the request returned. Where a source publishes its own timestamp (trade time, settlement time), PolyKal shows the source's time, never the visitor's clock.

Refresh schedule

• Pages are rebuilt about every 15 minutes. A rebuild is published only if it passes size, canonical and structure checks; otherwise the previous good page stays online.
• Large-trade feeds poll the public trade endpoints in the browser about every 20 seconds.
• Order books on compare and event pages are re-queried when the visitor asks, with a 10-second cooldown; the refresh time is printed next to the book.
• Cross-platform overview totals are recomputed once a day because they require paging through every open market.
• Suspected matches arrive once a day from the partner job. The date of the list is shown beside it.

When a source fails or goes stale

• A failed request shows “No data” (or “Query failed” on the event page). PolyKal never falls back to an older value while presenting it as current.
• A record missing one field shows “—” for that field only; the rest of the row is shown.
• If a platform stops trading (Polymarket paused for about 2.5 hours on 2026-09-03), the large-trades feed simply shows the time of the last fill. A long gap is a market condition, not a data fault.
• Kalshi fills carry no trader identity, so Kalshi rows never show an address. Polymarket usernames are set by users and are not verified identities.

Known blind spots

• PolyKal's own capture covers a subset of Polymarket addresses and a subset of their fills; leaderboards rank what PolyKal has seen, not full histories.
• Neither platform publishes hourly price history publicly, so charts are daily.
• Suspected matching events are candidates from an algorithm; PolyKal does not certify that two markets settle on the same thing.
• Kalshi's public trade stream is anonymous; a large Kalshi fill cannot be attributed to an address.
• Fee estimates use each platform's standard taker formula with per-level cent rounding. Perpetuals and combination markets are excluded and show “—”.

Responsibility and change log

Data pipelines are owned by PolyKal data engineering; page content is reviewed by the PolyKal research team. Fee rates are checked automatically every day, and each platform's official fee documents are reviewed by hand at least monthly for Kalshi and at least quarterly for Polymarket.

• 2026-09-05: Data Sources page published; parameterised URLs marked noindex; one H1 per page.
• 2026-09-04: New site launched at the root domain; large-trade and compare snapshots baked into HTML.
• 2026-09-03: Fee formulas verified against the Kalshi fee schedule (2026-07-07) and Polymarket Help Center (2026-07-10).

Corrections

If a figure does not match the platform's own page, email [email protected] with the PolyKal URL, the platform URL and the time you looked. Confirmed errors are fixed in the next rebuild and noted here.

Independent tool. Not affiliated with, endorsed by, or operated by Polymarket or Kalshi. Data from public sources. Not financial advice.