V1 data overview
pmxt/v1/, 2026-02-21T18 to 2026-04-16T05, one Parquet file
per UTC hour, named polymarket_orderbook_YYYY-MM-DDTHH.parquet. The last hour
with data is 2026-04-15T08; the
21 files after it are empty
placeholders, see below.
This is PMXT's data. Collected and published by PMXT under CC BY 4.0 and mirrored here unmodified. PMXT published no overview of v1. Everything on this page was read from the files. Their project is at pmxt.dev.
Columns
Five columns, with everything else nested as JSON inside data.
timestamp_receivedtimestamp[ms, tz=UTC]never null
When the exporter ingested the event. The hour partition key.
timestamp_created_attimestamp[ms, tz=UTC]never null
The source timestamp that came with the event.
market_idstringnever null
The market the event belongs to.
update_typestringnever null
price_change or book_snapshot.
datastringnever null
Everything else, as a JSON string you have to parse. For a
book_snapshot it carries token_id, side,
best_bid, best_ask, timestamp, bids
and asks. This is why v1 is markedly slower to query than the later eras:
there are no columns to push a predicate into.
5 columns. The types above were read from
the footer of 2026-03-15T12,
not copied from documentation, so they are what your own reader will report.
nullable says whether the schema permits a null at all, which is not the same as
how often one appears.
Reading it
v1 re-snapshots a market roughly every 2 to 3 minutes and covers about half the markets
v2 does. Where the two overlap, v2 is the better source. The best_bid,
best_ask, bids and asks inside data show
what the book displayed, not what an order would have received; a replay that fills at a
touched price overstates fills, see A fill, from a price you touched.
What is wrong with this data
Treat v1 as a partial sample of its era: useful for presence and shape, never for completeness claims.
- About a third of traded markets are missing. Against on-chain fills, v1 has a book for 65.00% of the markets that traded, across the six hours we picked in advance for the audit, ranging 32.24% to 99.94% hour by hour. Separately, on the hours v1 shares with v2, v1 lacks 41.93% of the markets v2 holds, and v2 lacks 2.28% of the markets v1 holds. Two methods with no shared input point the same way. the audit's check against on-chain fills, and the v1 to v2 overlap comparison, 2026-08-31
- Roughly half of v1's fills are phantom, and that is the venue's behaviour rather than a fault in this archive. 46% to 48% in every measured v1 hour. Polymarket's relayer reported fills that the on-chain contracts then rejected; traders called these ghost fills, and Polymarket's own exchange upgrade of 2026-04-28, which brought new contracts, a rewritten order book, and fees charged at match time instead of order time, was aimed squarely at that class of failure. PMXT recorded what the venue reported, which is what an archive is supposed to do. The phenomenon ends at 2026-06-19: markets from that date onward carry none. No market is entirely phantom: every traded market has at least one real fill. So this affects fill counts, not which markets appear. Polymarket's note on the upgrade. the audit's check against on-chain fills for the percentages, Polymarket's upgrade notes for the cause, 2026-08-31
- The real data ends earlier than the listing suggests. v1's last hour with data is 2026-04-15T08. The 21 hours listed after it, 2026-04-15T09 to 2026-04-16T05, are zero-row placeholder objects of 214 bytes each. They are listed because the files exist. They hold nothing. hour census against the published v1 SHA256SUMS.txt, with object sizes, 2026-08-31
- No transaction hashes, so individual fills cannot be matched to the chain. v1 records no trades and has no transaction_hash column, so individual fills cannot be matched to the chain. The coverage ratio above matches markets, not fills. read from the files, 2026-08-28
1,224 of v1's 1,283 hours have no v2 hour beside them, so nothing there can show what v1 missed.
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