Alex is the co-founder and CEO of Patentext. He’s spent over a decade drafting patents for startups, unicorns like Uber and Dropbox, and everything in between. When he’s not obsessing over Patentext or running his climate tech-focused IP firm, he’s likely training for a triathlon or chasing a very fast border collie.
When a startup founder tells me they've "checked for prior art," I usually ask what that means. The answers range from "I Googled it" to "we had our patent attorney run a formal search" — and everything in between.
Prior art searching is one of the most misunderstood parts of the patent process. Here's what it actually is, what different types of searches tell you (and don't tell you), and how to think about prior art as a startup founder.
What is prior art?
Prior art is any evidence that your invention was already known before your filing date. In U.S. patent law, prior art includes:
- Patents and published patent applications (anywhere in the world)
- Academic papers, technical publications, and conference proceedings
- Products on the market
- Public disclosures of any kind — demos, presentations, website descriptions, social media posts
If a prior art reference discloses all the elements of your invention, your patent claim is anticipated — meaning it's invalid. If prior art discloses most elements, an examiner might combine references to argue your invention would have been obvious.
Types of prior art searches
Patentability search (also called a novelty search)
The most common type. A patentability search looks for prior art that could anticipate or render obvious the invention you're planning to patent. The goal is to assess whether filing makes sense and what claim scope might be available.
What it tells you: Whether similar inventions have been patented or published before. What claim language might be available based on what hasn't been done. Whether the investment in a full patent application is likely to yield meaningful protection.
What it doesn't tell you: Whether you'll infringe someone else's existing patent claims (that's a different search — see below). Whether your application will definitely be allowed. A patentability search is a sampling of the prior art landscape, not an exhaustive review.
Freedom to operate (FTO) search
An FTO search looks at issued, unexpired patents to determine whether a product or process you're building or selling might infringe existing patent claims. This is a different question from patentability — you can have a patentable invention that also infringes someone else's patent.
FTO searches are typically done by patent attorneys and are significantly more expensive than patentability searches, because they require a legal analysis of claim scope, not just a literature review. A full FTO opinion might cost $5,000–$15,000 depending on the technology and the number of relevant patents identified.
Most early-stage startups don't commission formal FTO opinions until they're getting close to a product launch or a fundraise where investors will scrutinize IP risk. At the seed stage, a general awareness of the patent landscape is often sufficient.
State of the art search
A broader landscape search that maps the existing patent activity in a technology area, without necessarily focusing on a specific invention. Useful for competitive intelligence: who is filing patents in your space, what are they covering, and where are the white spaces?
State of the art searches are particularly useful for founders in crowded spaces like AI, medical devices, and chemical processes, where the patent landscape is dense and understanding who holds what can inform both product strategy and IP strategy.
Validity/invalidity search
A search specifically intended to find prior art that could invalidate an existing patent's claims. Used in litigation, licensing negotiations, and due diligence. If you're worried about a competitor's patent and want to challenge it (or understand its vulnerability), this is the search you need.
How to do a basic patentability search yourself
You don't need to commission a formal search to get a sense of the prior art landscape. Here's a practical approach:
- Search Google Patents and Espacenet: Google Patents covers US patents and many international filings. Espacenet (European Patent Office's database) has broader international coverage. Search for key technical terms describing your core innovation.
- Search the USPTO's Full-Text Database: patents.google.com is actually powered by Google Patents, but the USPTO's own PatFT and AppFT databases allow more structured searches.
- Use classification codes: Patents are organized into classification codes (CPC codes) by technology area. Once you identify a relevant CPC code, you can search all patents in that class — often more effective than keyword searches.
- Search academic literature: Google Scholar, IEEE Xplore, PubMed, and arXiv are useful for finding published research that might constitute prior art, especially in technical fields where academic publication predates commercialization.
- Document what you find: Keep records of your search. If a prior art issue comes up during prosecution, you'll want to demonstrate you conducted a reasonable search and understand how your invention distinguishes from the prior art.
When to commission a professional search
A self-conducted search is useful for initial orientation. But there are situations where a professional search — conducted by a patent agent, patent attorney, or specialized search firm — is worth the investment:
- Before filing a non-provisional: A professional search can inform the claims strategy and help you understand what scope is realistically available. It often costs $800–$2,000 and can save multiples of that in prosecution costs by helping you draft better claims.
- Before significant product investment: If you're about to invest heavily in a product that could infringe existing patents, an FTO analysis is worth doing.
- During fundraising or acquisition due diligence: Investors and acquirers often want to see evidence that a patentability search was conducted and that the IP position is defensible.
Limits of prior art searching
No search is exhaustive. The USPTO's own examiners — who conduct professional searches as part of their job — routinely miss prior art. Pending patent applications are published 18 months after filing, so there's always a window of unpublished applications that won't show up in any search. International filings in smaller patent offices may not be well-indexed in the major databases.
This is why claims in a patent are often narrower than the inventor initially hoped: during prosecution, examiners identify prior art that the applicant didn't find, and claims get amended to distinguish from it. A good prior art search reduces (but doesn't eliminate) this risk.
How Patentext approaches prior art
Patentext incorporates a structured prior art search as part of the patent strategy development process. Before drafting your application, we identify the most relevant existing patents and help you understand how your invention distinguishes from the prior art — so the application is drafted with that context in mind, not retrofitted to deal with it later.
Get your patent strategy for free
This article is for informational purposes only and does not constitute legal advice. For guidance specific to your invention and situation, speak with a qualified patent professional.