AI Reignites the Build-Versus-Buy Debate in Legal

AI Reignites the Build-Versus-Buy Debate in Legal

Jeff Marple
Senior Director, Harbor Labs

When it comes to legal technology, particularly in the era of artificial intelligence, legal departments and law firms face an age-old question: should we build our own tools, or buy from a vendor?

The answer, of course, is rarely absolute.

Most organizations will find themselves somewhere in the middle, combining purchased technology with tailored customization of that technology, to meet their unique needs. The arrival of generative and agentic AI has reignited the build-versus-buy debate.

There’s a perception that AI can “solve everything,” but the reality is more complex. AI may extract or surface information from contracts, discovery documents, or client data, but organizations still need intuitive, user-friendly systems around it: ways to input clean data, ways to present insights to users, and workflows for acting on the output. This is where the decision to buy, build, or blend comes into play.

For most mainstream use cases, such as contract lifecycle management (CLM), buying from a vendor provides significant advantages. Vendors have been asked the same questions thousands of times and have built scalable answers into their platforms. They also offer economies of scale, compliance guardrails, and user-friendly design that individual legal teams would find costly to replicate from scratch.

One consideration that is often left out of the build/buy calculus is the cost of support. 1.0 is only that: the first version of the application. The world will continue to change around it. Regulations, requirements, macroeconomic trends, and technology continue to evolve, and the application has to keep pace, or it will lose value with each day that it cannot respond to those changes.

In these cases, the smarter path is often to buy a platform and take advantage of its built-in capabilities, then extend or configure it to fit the organization’s particular processes.

Then there are scenarios where building becomes the only realistic choice. Specialized industries may require contract structures or workflows so unique that existing platforms fall short. If no vendor supports your use case, building a custom solution may be necessary.

Building can also be a valuable learning exercise. Low-risk, low-cost pilots can help legal teams explore what AI can and cannot do before committing to a long-term vendor investment. Done thoughtfully, custom builds give teams hands-on experience with emerging technologies while illuminating their real-world limitations.

The Hybrid Reality

According to Harbor’s 2025 Law Department Survey, law departments are moving beyond exploration and into active deployment with AI-based tools. The majority have implemented or are piloting tools for productivity, summarization, and legal research. Almost half of departments reported exploring AI for compliance, privacy, or changes in law.

Most organizations will buy core systems but then customize around them. The critical questions to consider are:


  • How will the tool access the data? Is the data clean, complete, and accessible enough for the system to process?

  • What will AI do with the data? Does the tool address actual business questions, or just deliver raw information?

  • How will your team use the output? Are there dashboards, workflows, or integrations in place to turn insights into action?

If the answer to these questions is “we’re covered,” buying is probably the right move. If the answer is “not yet,” you may need to build -- or at least customize -- components around the purchased platform. At the very least, you should think long and hard about how to answer these questions. Readiness of intention and of your data can be critical success factors with any technology project.

The prospect of agentic AI means even more importance should be placed on these assessments, as issues with data hygiene and outputs can compound once AI is deployed in multi-step workflows.

A Moving Target

It’s important to remember that technology is evolving rapidly. What seems impossible today may be available off-the-shelf tomorrow, and costs will come down over time. A flexible approach -- one that allows you to re-evaluate as the landscape changes -- is the best safeguard against overcommitting in either direction.

The real question isn’t “build or buy?” but rather, “how do we combine both approaches to maximize value?” Legal departments and law firms that strike that balance by leveraging vendor platforms where they exist, building when they must, and always focusing on the user experience and data readiness, will be best positioned to navigate this new era of legal technology.