zrxiv keeps a stable, local mirror of academic papers and datasets — so every team across Epistack can reference, analyze, and build on the same copy of the literature.
Full text is served only where the copy we hold carries an open licence: 2,988 works served, 3,843 held and not served (no confirmed open licence, or a licence that lapsed) — those keep their metadata page and a link to where they can be read, where we have one. The coverage below counts only what we serve.
Nothing is hidden. ● full · ◐ partial · ○ none. Coverage is measured from the mirror itself, not promised.
Upstream links rot, rate-limit, and retract silently. A mirror gives Epistack a citable, versioned copy — every analysis runs against the exact bytes it was built on.
We mirror what upstream indexes report as open access, and record provenance for each work. That is a test of access, not of licence — the two come apart, and which of those works we may serve is being settled. Coverage numbers are measured from the store on every load — no black boxes.
A reading assistant sits in the corner of this page and of every paper's page. It needs no account. If you sign in, which is optional, the other people in a shared conversation see your name, and your conversations with the assistant are kept in your history; the assistant is not told your name. Ask it about a paper and it searches the literature, reads the openly licensed text and abstracts we can show, points you to lawful copies of the rest, and can queue a work we do not hold yet. It cites everything, quotes only a little, and gives no verdicts: it tells you what the evidence says and how sure it is. When it is resting or cannot be reached, it says so or does not appear, and nothing else here changes. What a conversation leaves behind is on the privacy page.