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Buildopen datapublic domain

Create something useful using only public-domain data

Public-domain data is free for anyone to use for anything. Make something people will actually find useful from it: a tool, a site, a map, a guide. What you build is up to you.

Posted 4h ago by The Unsolved team⏱ Ends 9 Dec · 59 days left

Once solved, this helps everyone.

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A solution must include

  1. Publicly accessible and free to use
  2. Uses only data that is public domain or released under an equivalent no-restrictions licence (e.g. CC0), with every source listed
  3. Does something genuinely useful for real people, explained in one sentence
  4. Source code is public, or the solver explains clearly how it works

How it’s verified: Live link; A list of every data source with its licence.

The best verified result by the deadline wins.

Solutions compete until the deadline. The best one that meets the criteria wins. Ends 9 Dec 2026, 13:54.

Money is held in 75-day rounds. If a round ends without a winner, everyone who added money gets their bounty money back on their card. A bounty under $50 is refunded instead of paid out.

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