Who publishes prior art, and why
People publish on Open Prior Art for six main reasons: to keep the freedom to use their own invention without paying for a patent, to create prior art in a field before others patent it, to give an invention to the world, to keep open-source hardware free of patents, to put research details on record, and, for companies and patent owners, to protect ideas they won't patent. The publishing steps are the same; what to write differs.
Inventors who can't or won't pay for a patent
Goal: keep the right to make and use your invention, without a competitor patenting it and blocking you.
What to publish: the invention in full detail, with drawings, an example and the variants you can think of.
Watch out: you will most likely lose the chance to patent it yourself. Decide that first. See how to stop others patenting your invention.
Creating prior art in your field
Goal: some fields get crowded with patents on small steps and obvious variations. Publishing those steps and variations before anyone files them keeps them free for the whole field. Some companies do this deliberately: they publish a ring of small improvements around a product so that nobody can patent them.
What to publish: concrete technical solutions and their alternatives: other materials, ranges of dimensions, other ways of joining or controlling the same thing, applications in neighbouring fields. Each variant you describe clearly becomes prior art of its own.
Watch out: it only works against applications filed after your publication date, and only for what you actually describe. Lists of buzzwords or vague "it could also be done with AI" lines don't create useful prior art, and we don't publish them.
Giving an invention to the world
Goal: you want your idea used as widely as possible, by anyone, for free, and you don't want anyone to lock it up with a patent.
What to publish: everything needed to build it. Entries are published under CC BY 4.0, so anyone can reuse your text and drawings as long as they credit the source. See how to give your invention to the world.
Open-source hardware and maker projects
Goal: keep a shared design free. Open-source licences cover the design files, but they don't stop a third party from patenting the underlying technical idea or an obvious improvement to it.
What to publish: the working principle and key technical features of the design, its important variants and the improvements the community is discussing, with a link to the project repository in the references.
Watch out: publish early, ideally when the design is first shared, and again when significant improvements arrive.
Researchers and universities
Goal: papers rarely contain every useful variant, practical detail or engineering trick. Publishing those details keeps them free and gives them a citable, dated record.
What to publish: methods, set-ups, compositions and variants that won't make it into a paper, with references to the related papers.
Watch out: check with your institution's technology-transfer office first. Many universities want to decide about patents before anything is published, and some results may belong to a funder or partner.
Companies: ideas you won't patent
Goal: most companies have far more ideas than patents. For ideas that aren't worth a patent but must stay free to use (features, manufacturing tricks, alternatives), a defensive publication costs nothing and keeps competitors from patenting them.
What to publish: the technical solution, without trade secrets. You can publish anonymously or under the company name.
Watch out: make sure the person publishing is authorised to do so for the company, and don't publish anything that is still meant to be patented.
Patent owners: improvements you won't patent
Goal: if you hold a patent, competitors may try to patent improvements around it and box you in. Publishing the improvements you don't plan to patent keeps them open, for you and everyone else.
What to publish: the improvements and alternative embodiments, each described clearly.
Watch out: a publication can also become prior art against your own later patent applications. Coordinate with whoever handles your patents.
Questions
Can a company publish on Open Prior Art?
Yes. Any person with a verified account can publish, including on behalf of a company if they are authorised to. The entry can show the company name or stay anonymous.
Can I publish variations of someone else's patent?
You can publish your own technical ideas, including improvements and alternatives in a field where others hold patents. Publishing does not give you the right to use their patented invention, and you must not copy their text or drawings.
Is publishing allowed for open-source hardware?
Yes. Open-source licences cover the design files; a defensive publication adds a dated, findable record of the technical idea itself, which helps keep it free of patents.