About Open Prior Art

A free, public registry where anyone can publish a technical disclosure with a date that can be proven, so that nobody can patent it later.

Why publish an invention?

A patent is only granted for something new. Once an invention has been made public, it is "prior art", and a later patent application for the same thing should fail. Companies have long used this, called defensive publication, to keep their freedom to use an idea without paying for a patent. Open Prior Art makes it free and simple for everyone: inventors, makers, small companies, researchers.

The catch: you most likely lose the right to patent it yourself, anyone may use your idea, and nothing guarantees that an examiner will find it. Read the full "Before you publish" notes.

People publish here for different reasons: to stop others patenting their idea, to create prior art in their field, to give an invention to the world, or to keep open hardware, research and unpatented company ideas free. See who publishes prior art, and why.

How it works

1. You write it. A guided form: the problem, the detailed description, an example, variants, and up to five drawings, in any language, with an English title and summary. Our software only points out gaps; it never writes for you.
2. We review it. During the beta, a person reviews every submission. We check that it is a technical disclosure that follows the terms, not whether the invention is new or good.
3. It is published, with proof. It gets a permanent number (OPA-year-number), a public page, a content fingerprint, independent timestamps and an Internet Archive copy, and you get a Certificate of Publication.

How the proof works, and how to check it without us

Three independent records show what was published and when, so the proof does not depend on us alone:

• The registry. Each entry's exact content is saved as a file, content.json, linked from the entry. Its SHA-256 fingerprint is shown on the entry and the certificate. Anyone can recompute it: sha256sum OPA-2026-000001-content.json.
• Independent timestamps. The fingerprint is sent to two independent RFC 3161 timestamping services, which sign it together with the time. The signed tokens can be downloaded from the entry and checked with standard tools, for example: openssl ts -reply -in OPA-2026-000001-freetsa.tsr -text. To verify a token fully, download the service's own certificates from its website and run openssl ts -verify -data OPA-2026-000001-content.json -in OPA-2026-000001-freetsa.tsr -CAfile cacert.pem -untrusted tsa.crt.
• The Internet Archive. A copy of each entry page is saved in the Wayback Machine, run by a separate non-profit.

Drawings are included through their own fingerprints, listed in content.json. The author's identity is not part of the fingerprint, so a later change from a name to "Anonymous" does not affect the proof.

Who runs it

Open Prior Art is operated by Adria Intellectual Property, Croatia. It is not a patent office and gives no legal advice. Publishing and searching are free.

Questions or problems: [email protected]. To report an entry that breaks the terms, include its number.