Data retention
Polymarket Data Retention Explained
Retention is the quiet guarantee behind every study: resolved markets stay in the archive with their full 250ms history and the outcome on every row. This page explains what retention means on Polymarket, what the plan windows limit, and what never disappears.
Figures measured as of 2026-09-24 on the published PolyOrderbooks archive.
The short answer
Resolved data is permanent; access windows are not
The archive retains resolved markets indefinitely: books, prices, metrics, and outcomes remain queryable at 250ms after resolution, and nothing is deleted to make a balance sheet. The access window (3 free days, 30–120 paid days) governs how far back a key can query, not what exists.
The distinction is the honest core of this page: a data window is a license to read, a dataset's retention is a promise to keep.
After resolution
What post-resolution rows keep
Resolved rows keep every field the live rows had — full ladder, prices, metrics, flags — and add the winning outcome. That is what makes the resolved corpus of 118,251 markets a backtest surface rather than a feed.
The capture cadence also holds post-resolution for the settlement-minute frames, which is why final-second studies are possible at all.
Compare
Against the official API
The official API serves live state and a bounded price-history window, so past depth is only preserved by something that recorded it. The archive's retention is that recorder: the same official vs archive distinction, applied to time.
The honest planning consequence: anything you will need in a month must be pulled into your own store or archived for you now.
Honest
The honest framing
Retention is advertised in the API documentation and enforced in the dataset: the site states on each product page what windows exist and the dataset keeps everything it promised, because a dataset that silently truncates is worse than one that never claimed permanence.
FAQ
Do resolved markets stay available?
Yes — the archive keeps resolved markets with full 250ms history and the outcome on every row; nothing is deleted after resolution.
What does the 3-day window mean?
Starter can query 3 days back; paid windows extend to 30–120 days. The window is an access license, not the data's lifespan.
Why keep settlement-minute frames?
The final-second and final-minute structure (76.2% single-sided) only exists if the frames are retained post-resolution.