FTO and Open Source: The Overlooked Patent Risk in "Free" Code
Most companies building a new product today are not writing every line of code from scratch. They are pulling in open source components: libraries, frameworks, plugins, and entire chunks of functionality that someone else has already built and shared with the world for free. It is faster, it is cheaper, and honestly, it is just how modern software gets made.
But here is the part that catches a lot of founders and product teams off guard. "Free" open source code refers to the license under which you can use the software. It does not mean the code is free of patent risk. Those are two completely different things, and mixing them up can turn into a very expensive lesson.
What FTO Actually Means, in Plain English
Before getting into the open source angle, let's quickly cover what a Freedom to Operate search is, since not everyone in a company deals with this regularly.
A Freedom to Operate search, or FTO for short, is basically a check you run before launching a product to see if you are about to step on someone else's patent. Think of it like checking a map for toll roads and private property before a road trip. You are not checking whether your product is new or clever. You are checking whether making, using, or selling it would infringe a patent that someone else already owns.
Most companies are pretty good about running this check on their own inventions. If your engineering team built the core feature in-house, someone usually remembers to ask "wait, is this patented by someone else?" But that same diligence often disappears the moment open source code enters the picture, and that is exactly where the risk hides.
The Big Misunderstanding: License Clearance Is Not Patent Clearance
Here is the mental shortcut that gets a lot of teams into trouble. When a company brings in an open source library, the legal or compliance review usually focuses on the license. Is it MIT? Apache 2.0? GPL? Can we use this commercially? Do we need to share our own source code because of it?
Those are all fair and necessary questions. But they only address the copyright side of things, meaning who owns the code and under what conditions you are allowed to copy, modify, or distribute it.
Patents are a completely separate legal animal. A patent protects an invention, which could be a technical method, a specific algorithm, a particular way of processing data, or a specific system design. It does not matter who wrote the code or what license they slapped on it. If the code implements a patented method, and the patent owner has not given permission to use it, running that code can create patent infringement exposure regardless of how generous the open source license is.
So a library can be completely fine from a copyright and licensing standpoint, and still carry a patent landmine underneath it.
How This Happens in Real Life
Let's make this concrete with a simple, made-up example.
Imagine a startup building a video editing app. They find a well-maintained, popular open source library that handles a specific type of video compression really efficiently. The license is permissive, the documentation is great, thousands of other projects use it, and it saves the engineering team months of work. Everyone is thrilled.
What almost nobody stops to check is whether the underlying compression technique used inside that library is covered by an active patent. Compression algorithms, especially in audio and video, have historically been a minefield of patents held by large media and technology companies. Some open source implementations of these techniques exist specifically because the patent has expired, or because the community negotiated licensing terms, or sometimes because nobody involved actually checked and it just has not become a problem yet.
That last scenario is the dangerous one. Plenty of open source code exists and works perfectly well despite carrying unresolved patent risk, simply because the patent owner has not decided to enforce it yet, or has not noticed. That can change the moment your product becomes commercially successful and shows up on someone's radar.
Why Popularity Does Not Equal Safety
There is a common assumption that if thousands of companies are already using an open source library, it must be safe. Surely someone would have caught a patent problem by now, right?
Not necessarily. A few reasons this logic falls apart:
Patent owners often wait for the right target. Many patent holders, especially the ones running licensing programs as a business strategy, are not interested in going after a hobbyist project or a small open source maintainer with no money. They wait until a well-funded company builds a commercial product around that code. At that point, suddenly the phone rings.
Widespread use does not equal legal clearance. Just because a library is popular does not mean any lawyer has ever reviewed it for patent risk. Most open source adoption decisions are made by engineers looking at functionality and performance, not legal exposure.
The risk can be buried several layers deep. Your team might carefully vet the main library you are importing, but that library itself might depend on other smaller libraries, which depend on still more libraries. Patent risk can be sitting three or four dependencies down, completely invisible unless someone actually goes looking.
Why This Matters More for Certain Technology Areas
Not every corner of software carries equal patent risk. Some fields have a long, well documented history of aggressive patent filing and litigation, which makes open source components in those areas worth extra attention. A few examples worth knowing about:
Audio and video compression and streaming. This is one of the most heavily patented areas in all of technology. Codecs, streaming protocols, and playback techniques have been the subject of patent pools and licensing programs for decades.
Wireless communication and networking. Anything touching cellular standards, Wi-Fi, or Bluetooth tends to sit inside a dense web of what are called standard essential patents, meaning patents that cover technology baked directly into the technical standard itself.
Machine learning and AI techniques. This is a newer but fast growing area. Specific training methods, model architectures, and inference optimizations are increasingly being patented, and a lot of open source AI code implements these techniques without anyone checking whether a patent covers the underlying method.
Payment processing and financial technology. Certain transaction verification, fraud detection, and payment routing methods have attracted patent filings, especially from larger financial institutions protecting their systems.
If your product touches any of these areas and leans on open source components, that is a strong signal to look a little closer before shipping.
What This Means for an FTO Search
The practical takeaway here is that a proper Freedom to Operate search cannot stop at reviewing the code your own team wrote. It needs to extend to the open source components sitting inside your product too, especially the ones handling core technical functionality rather than boilerplate or utility tasks.
A thorough approach usually involves a few steps:
Build a real inventory. You cannot assess risk on code you do not know you are using. This means mapping out not just the libraries your team directly imported, but their dependencies too, since risk often hides a few layers down.
Flag the components doing actual technical work. A library that formats dates or handles basic string manipulation is extremely unlikely to carry patent risk. A library implementing a specific compression method, a specific machine learning technique, or a specific communication protocol deserves a closer look.
Check for known patent history in that space. Some technical areas have well known patent pools, licensing programs, or litigation history. If your open source component sits in one of these spaces, that is worth investigating specifically.
Look at what the open source community itself has said. Sometimes maintainers or contributors have already discussed patent concerns in issue trackers, mailing lists, or documentation. This is not a substitute for a proper search, but it can be a useful early signal.
Loop in a patent professional for anything that seems genuinely core to your product. If a piece of open source code sits right at the heart of what makes your product work, and it touches a technology area with a history of aggressive patent enforcement, that is worth an actual professional opinion rather than a guess based on gut feeling.
A Word on Risk, Not Panic
None of this is meant to scare anyone away from using open source software. Open source is one of the best things to happen to modern technology, and the vast majority of components carry no meaningful patent risk at all. Most code is doing ordinary, unremarkable things that nobody has patented or would ever try to patent.
The point is simply that "open source" and "patent safe" are not the same statement, even though they often get treated that way in practice. A little bit of targeted diligence, focused specifically on the technical core of your product rather than every single dependency you have ever imported, goes a long way toward avoiding an unpleasant surprise down the road.
The companies that get burned by this are rarely the ones who ignored FTO altogether. More often, they are the ones who did a careful FTO search on their own original engineering work, felt confident, and never thought to ask the same question about the open source pieces sitting quietly underneath it all.
That blind spot is exactly what a well scoped FTO process should be built to catch.
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