zPredict · last updated 2026-10-23
Privacy Policy
Plain-language notes for a hackathon demo. Not legal advice, and not drafted by a lawyer.
zPredict collects no accounts, cookies or analytics. Your account tag stays in your browser; each relayer holds only random shares. The hosted demo has two limits you should know: Cloudflare sits in front of it, and all three relayers run on one server.
Who we are
zPredict is an open-source hackathon project (Zecathon 2026), not a company. The hosted demo is zpredict.site, app.zpredict.site and three relayers at r0, r1 and r2.zpredict.site. Evidence for every statement here is in PRIVACY.md.
What we don't collect
No accounts, names, emails or KYC. No cookies. No analytics or trackers in our code. Our web servers keep no access logs, and fonts and scripts are self-hosted: the pages make no requests to third parties.
What stays in your browser
The app keeps your account tag (the only key to your balance), your orders with their shares and read tokens, and a judge claim in progress, in your browser's localStorage. The tag is never sent anywhere whole.
“Forget this account” (under Deposit) or clearing the site's data deletes them. Nobody, including us, can restore a lost tag, so a balance tied to it is lost too.
What each relayer receives and keeps
Your browser splits every order into three random shares and sends one to each relayer. Each relayer keeps, in an event log on its own volume: its share of each order and fill, its share of each account's key and balance, and the read tokens. One share alone reveals nothing; all three together reveal everything.
Each relayer also sees each deposit's amount, time and account id, and each withdrawal's amount, destination address and time (it needs them to pay). It does not learn whose withdrawal it is, except through request metadata and amount and timing (#90, #91).
Public to anyone: the market list, outcomes and their signatures, one clearing price per market per batch, and a digest (not the content) of each share a relayer received.
Who else can see what (demo limits)
Cloudflare proxies the sites and relayers and terminates TLS, so it sees your IP address and, until #88 is fixed, everything sent to the relayers in clear. It also adds an analytics script our security policy blocks, and a header asking your browser to report network errors to Cloudflare (#89).
All three relayers run on one server, so its operator could read every share. The privacy model needs three independent operators.
Your network provider sees that you connect to zpredict.site and when, not what you send. Tor hides your IP address.
Other services
For mirrored markets the relayers fetch public market data from Polymarket on the server side; Polymarket sees the server's address, never yours. Your browser never contacts Polymarket: a Polymarket link loads only if you click it, without a referrer.
The relayers read Zcash blocks from public lightwalletd servers (zec.rocks, testnet.zec.rocks). When you deposit, your own wallet's server sees your IP address.
How long data is kept
Relayer event logs stay on the relayers' volumes while the demo runs; nothing expires automatically. Operator logs hold start-up lines and errors, never an order, share, account or address. This is a testnet demo: all of it may be wiped at any time.
We can't look up or delete “your” records on request: we don't know which ones are yours.
Changes and contact
Changes are made in the public repository and update the date above. Questions: GitHub issues.