Api disputes in software litigation: what courts need to know about interface claims

APIs are the backbone of modern software. They connect applications, power integrations, and enable different technologies to work together seamlessly. But when a software lawsuit arises, APIs can also become a source of legal complexity, especially regarding copyright claims, trade secret issues, and the protection limits.

At Eureka Software, we’ve supported legal teams in navigating the technical and legal nuances of API disputes. Whether a case involves allegations of copying, unfair competition, or unauthorized use, understanding how APIs work—and when they are (or aren’t) protected by law—is critical.

In this blog, we’ll break down:

What Is an API, Anyway?

An API (Application Programming Interface) is a set of rules and definitions that allow different software systems to communicate. Think of it as a restaurant menu: it tells you what dishes you can order (functions), what ingredients you need (parameters), and what you’ll get back (the response).

In technical terms, APIs typically include:

APIs are essential because they allow developers to build on existing systems without reinventing the wheel. But when a legal dispute arises, the question becomes: Is the API itself protected intellectual property—or just a functional tool that anyone can use?

When Can an API Be Copyrighted?

This is where things get tricky.

Historically, U.S. courts have debated whether API elements are protectable under copyright law. The key case in this area, Google LLC v. Oracle America, Inc., reached the Supreme Court in 2021. The Court ruled that Google’s use of Java API declarations in Android was fair, meaning copying those parts of the API was legal under the circumstances.

But the Court also left the door open for future disputes. API protection depends on factors like:

Can an API be copyrighted? The answer depends on the specific case, how the API is implemented, and how it’s used.

Common API Disputes in Litigation

API-related legal disputes often arise in cases involving:

For courts, the core questions often become:

How Eureka Software Analyzes API Disputes

At Eureka Software, we bring technical clarity to these legal gray areas. Our API analysis process includes:

1. Detailed API Mapping

We compare API endpoints, method signatures, and call structures across products to identify:

We also analyze whether similarities stem from standard industry practices or are unique to the plaintiff’s system.

2. Source Code Review

When code is available, we examine how the API is implemented:

3. Documentation and Access Analysis

We assess whether the API was:

This helps determine whether the defendant had legal access to the API in the first place.

4. Industry Standards Review

Our experts evaluate whether API designs align with industry norms or reflect proprietary, original work. For example:

5. Expert Testimony

We translate technical findings into clear, objective reports and courtroom testimony, helping judges and juries understand the nuances of API functionality, originality, and potential infringement.

What Courts Need to Know

When API disputes reach the courtroom, legal teams, judges, and juries must understand:

Eureka Software Brings Clarity to API Disputes

API disputes are some of the most complex issues in software litigation, at the intersection of functionality, creativity, and legal interpretation. At Eureka Software, we provide the expertise to analyze APIs, compare systems, and present findings clearly, whether you’re defending against an infringement claim or enforcing your IP rights.

If you’re facing an API-related dispute, contact Eureka Software today to learn how we can help you confidently navigate the technical and legal challenges.